TDIClub Forums

TDIClub Forums (http://forums.tdiclub.com/index.php)
-   VW MKIV-A4 TDIs (VE and PD) (http://forums.tdiclub.com/forumdisplay.php?f=12)
-   -   Definitive Battery Thread??? (http://forums.tdiclub.com/showthread.php?t=58342)

GD December 29th, 2008 17:02

[quote=Stringer]
Quote:

Originally Posted by GD
I returned my batttery after 2yrs to Costco as it only had a 60ah rating (after calculating the reserve capacity x 0.6) as the battery was intended for a 97 AAZ TD Jetta as they didn't stock one for a A4 ALH TDI. Once the glow plugs had cycled the battery had a hard time spinning the starter, hence the need for a 80ah. They took it back no questions asked as up in Canada they don't stock the 94R. I bought a reconditioned 94R (MTP-H7) from an Intersate Dealer for $40 including core.

Forty dollars, that is an awesome deal:). I take it you just recently got that battery? Did you have to search a lot to find the dealer?

There are 2 Interstate Dealers in the Toronto area that recondition the batteries one sells the Econo Power battery for $35 with a 6mth warranty the other sell it for $40 with a 12mth warranty. Both prices include a $5 core discount.

GD December 29th, 2008 17:03

Quote:

Originally Posted by MAXRPM
I remembered when driviwire came to SF bay area and he happened to do my TB in my other Jetta car about 3 years ago in a GTG, he strongly suggested to me that I should change the Yellow top Optima battery, he said that it was not going to last,,,,and it is up until now the battery has been a true champ in the same car. fires right up no problem I am a Ham and have a 600 W linear I talk at night and I have abused this battery and no sign of giving up so I have really put it to a test.

Now a days I'd hate to buy this battery, because it is pricey, when I purchased around 03, I paid like $96.00 now they are like way up there on the price, that is why I am staying away from them. otherwise yellow top would be my top choice.

I am going to give a try to an interstate reconditioned battery, I got a interstate dealer just a block away from my work place, which model number is a good interstate battery for the TDI, is it MTP-H7? so I could request for one, and if it fails down the line, I will buy the OEM.

MTP-H7 is a 94R equivalent with 640 CCA and a 80ah rating

MTP-H7 640CCA 135 min reserve capacity
MTP-91 700CCA 120 min reserve capacity

Is it 135RC x 0.6 = 81ah
Is it 120RC x 0.6 = 72ah

So the MTP-H7 is best

d2305 December 29th, 2008 17:05

I put in a group 91 blemished interstate for $30. Works fine.

MAXRPM December 30th, 2008 10:23

Quote:

Originally Posted by GD
MTP-H7 is a 94R equivalent with 640 CCA and a 80ah rating

MTP-H7 640CCA 135 min reserve capacity
MTP-91 700CCA 120 min reserve capacity

Is it 135RC x 0.6 = 81ah
Is it 120RC x 0.6 = 72ah

So the MTP-H7 is best


Which one of these two models of battery is the one that you have mod the plastic battery cage to make it fit because the battery is too long?

GD December 30th, 2008 10:29

Quote:

Originally Posted by MAXRPM
Which one of these two models of battery is the one that you have mod the plastic battery cage to make it fit because the battery is too long?

Neither of these need modification of the battery box

MAXRPM December 30th, 2008 10:41

Quote:

Originally Posted by GD
Neither of these need modification of the battery box

Thanks to all the battery gurus, I just called Interstate dealer which is around the corner from my work place and the they have both of the Recon-batteries, the MTP-91 is $27.00 and the MTP-H7 is $35.00 + tax, so I am going for the MT-91 since I imagine It's lighter and shorter than the MTP-H7, I will give it a shot and come back with the results down the line, I hope it lasts.

TDIMAXIMA January 19th, 2009 15:02

Quote:

Originally Posted by GD
MTP-H7 is a 94R equivalent with 640 CCA and a 80ah rating

MTP-H7 640CCA 135 min reserve capacity
MTP-91 700CCA 120 min reserve capacity

Is it 135RC x 0.6 = 81ah
Is it 120RC x 0.6 = 72ah

So the MTP-H7 is best

How much better? What number matters the most for cold starts?

puter January 19th, 2009 15:24

Ah is what you want to look at.

With cca, either you have enough pipe to start the engine or you don't...and both of them have enough. Ah indicates exactly how much energy the battery can store.

IMO: the MTP-H7 will do fine unless you have additional devices demanding power.

TDIMAXIMA January 19th, 2009 15:59

Such as?

puter January 19th, 2009 19:34

Quote:

Originally Posted by TDIMAXIMA
Such as?

could you clarify what you are asking?

shagin'wagen January 19th, 2009 19:50

Well, I finally got the proper battery for my car. WOW! That thing is massive! The car almost lights off immediately, and is actually a tad bigger than one in my dad's Cummins, but it has 2.;)

Stringer January 20th, 2009 18:33

Quote:

Originally Posted by TDIMAXIMA
How much better? What number matters the most for cold starts?

Ah is definitely the most important. Glow plugs warm over a few seconds and they draw a fair amount of power. The reserve of a high Ah battery is what is needed to do this and to then turn the starter.

CCA gives gas cars without glow plugs the big initial surge they need to start. In Markham I know it can get very cold (I used to live in East York) ... having the higher Ah will make you very happy.

weasel January 20th, 2009 23:13

XZ2, learned that the hard way. Have a 94R under the hood and a 48 spiral cell in the trunk. Nothing beats 2 batteries ...

blizzak February 2nd, 2009 18:19

Hey guys,

So I bought an optima red top not too long ago since I thought my battery had run it's course - it was an interstate MTP-91. I managed to kill my starter while I had the optima in there. The starter was most likely on the way out, but nonetheless, I knew I never should have bought the red top in the first place. Replaced the starter and it is like night and day, but I was still bitter. Luckily, the guy I bought the red top from allowed me to exchange it for an interstate MTP-H8. I was very happy with the exchange. Here are the stats of the MTP-H8:

CCA: 720
CA: 900
RC: 176, making Ah approximately 176 * 0.6 = 105.6!!!

A couple pics, since everyone likes pics:

http://pics.tdiclub.com/data/500/med...007_Large_.JPG
http://pics.tdiclub.com/data/500/med...008_Large_.JPG

Being a group 49, it just fits in the A3. Looks awesome under the hood in all its white glory. I put some foil tape on the caps so that dirt wouldn't get in there and thus contaminate the electrolyte when opening the caps in the future. I like it a lot better than the MTP-91 that was in there because acid doesn't spill out of a horizontal vent at the back...not sure who ever came up with that silly design.

It'd be cool for someone to comment on the Deka 9AGM49...I wonder if it would exhibit the same shortfalls as the optima despite having higher Ah. This MTP-H8 has 55 Ah more than the optima I had, 33 more than my MTP-91. Enough said.

Stringer February 3rd, 2009 11:08

RE: Blizzak

I have a Deka 9AMG49. I don't think the Optima is comparable.

The Deka has 95AH, 900CRA and 180 RC. I've had it for over a year and a half and even if my car has been sitting for a few days in -30 degree C and colder (temps you are used to :)) it starts no problem.

I don't think the Optima has the same capacity to heat the glow plugs over and over and retain enough juice to turn the starter strongly thereafter.

Only thing I would change about my battery is the size/weight and price.

blizzak February 3rd, 2009 12:49

Hey Stringer,

I assume you are in Windsor, Ontario, and not Windsor, California? Location is a little confusing on your profile

I think the main criticism of the application of an AGM is that the voltage given out by the charging circuit is too much, and apparently too much charging voltage can kill an AGM. Interesting discussion going on in the Optima Red Top SURVEY thread. It'll be good to see how yours holds up. I would have that same battery too if I wasn't limited to choosing from interstate after returning my red top. Definitely awesome Ah on that Deka though.

Stringer February 3rd, 2009 13:38

Re: Blizzak

Windsor Ontario. I better correct my info. I've also lived in East York, Bobcaygeon, NB, and Nfld :) Windsor California ha ha ... that would a be nice change ... I think.

I did get some input from other long time Deka owners before purchasing my battery. They live in much colder areas of Ontario and Quebec and had noting but positive things to say. I was also impressed with Deka's specialization in industrial and military applications.

iamalittlepepper February 4th, 2009 16:53

Hello!
Just to add another data point for people in Canada.

1J0915105AG/ 000 915 105 AG is $125 at westminsterVW dealership in BC.
Deka 9AGM48 is $158.54
Deka 9AGM49 is $194.51

Both directly from EastPenn.

The question for those who have the 1J0915105AG, does it have a vent tube? also which side is it on? It is not an AGM battery is it?

It might be the cheapest source of 94R battery out there. As even East Penn wants 150 for it.

Also according to some European websites, VAG meks a 000 915 105-AJ which gives 82Ah http://www.thetradepartsspecialists....Quantum-03.xls

BTW according to Varta's website, Varta is now owned by Johnson Controls.

ymz February 4th, 2009 21:20

If the VW 1J0915105AG was an AGM battery, it would cost substantially more...

And if you're talking about the 1J0915105AJ battery, look up the 1J0915105AH... that one is supposed to have 95 AH... (it's listed for some models of the Golf...)

Yuri.

volkswagendude February 21st, 2009 18:05

I have no experiences with Optima on TDI's, so I won't even get involved with that argument. I'm a true believer on hands on experience, and with that here's mine on my other car.
I've got an Optima on my "summer only" custom BMW, sitting in my unheated garage. Before I forget....you can now find Optima at Walmart at half decent prices btw.
Why did I choose Optima for this application? Because I have gone through about 4 Interstates in about a decade and simply got fed up. They can't handle the 6 month winter hibernation rest cycle, and the few drives that I do in the summer, when I actually do find the time to enjoy the car. The Optima on the other hand can handle these given application type of extremes that I subject it to, and thus far, no problems at all 4th year running knock on wood. Even if I was to go right now, to start my BMW for the first time in 4 months in my sub zero unheated garage, I do know that it will not only start, but spin quickly and engage with authority.
The only draw back to having selected this type of battery, is that I had to buy my own battery cable, because the OEM one was not long enough to reach the negative post, as the battery posts on these are reversed from OEM battery applications for my BMW. So chances are with an Optima, due to size and shape differences, you might have to do a small DIY custom job.
Would I install this on My B5.5 TDI? I'm not sure yet. I also don't know anything about the Optima not being well suited for our TDI's cranking needs in the cold, so I won't insist on something I have no knowledge on. So far, I have no complaints with the OEM one. However, (not sure if this applies to VW...) there is one documented concern with some manufacturers, including (especially)BMW. The OEM batteries from the factory itself, usually do last, no argument there, but consequent OM replacement batteries bought from the dealer, for SOME DAMN REASON, never ever ever compare, even come close to lasting like the virgin one from the factory did.

For me, the REAL question to beg is if Odyssey AGM batteries are the real deal. I think I might give that one a shot next time around I'm in the market for "the best."

ymz February 21st, 2009 18:14

Quote:

Originally Posted by volkswagendude
The OEM batteries from the factory itself, usually do last, no argument there, but consequent OM replacement batteries bought from the dealer, for SOME DAMN REASON, never ever ever compare, even come close to lasting like the virgin one from the factory did.

I was going to say something about the original batteries having been German-built whereas the replacements are local products, but... the battery on my 2003 Jetta died before the battery on my 2001 Golf... and both of those were of German manufacture...

If you want a battery made in the Vaterland, go to Autolectra on Paré... (they aren't cheap, though...)

Yuri.

volkswagendude February 21st, 2009 18:36

^^^Yuri, I just edited my post slightly if you want to reread it for the sole purpose of entertaining/educational reading :D

Small world, we've probably crossed paths and haven't even known it. I've been shopping from Autolectra on Pare for over a decade, although I must openly say, I'm not as happy with the service the last couple of years, or ever since Francis left. I used to custom order stuff straight from the motherland through him, whether it be custom Hella parts, or what not. Now I find that they have gone more generic and "mainstream", and God oh God how I hate that with a passion. The parts guys are nowhere near as knowledgeable, and even when I provide them with the part#'s(which I always have ready in hand wherever I go) they are still not willing to..........anyways, I'll stop venting and rambling on as that's an other topic all together.

In any case, I'll check out the battery you are talking about.

shadows May 19th, 2009 06:54

Bad "new" battery?
 
I'd been having hot-starting issues for awhile now. Thought replacing the starter and the battery would help. No luck. I'm looking into Hamman's mod now.

When I replaced the battery at Autozone, I had to go with a Canadian spec battery as it was all that was available. It actually had better ratings than the previous (which doesn't say much). It's rated at 650CCA, 810CA, and 110 reserve capacity. However, I swear the battery isn't performing as well as the previous one. On top of this, the battery looked used. I questioned the guy on this when I purchased it, and he suggested it was just because it had been on the shelf for awhile. Stupid of me to trust him, eh?

I can't think of any difference that Canadian "model" battery would have if the other specifications are good or better. Did I just get a junk battery? If so, I will be making a fuss. Also, should I shoot for something rated higher if I return the thing? Any recommendations?

Thanks a bunch!

puter May 19th, 2009 11:31

Quote:

Originally Posted by shadows
I'd been having hot-starting issues for awhile now. Thought replacing the starter and the battery would help. No luck. I'm looking into Hamman's mod now.

When I replaced the battery at Autozone, I had to go with a Canadian spec battery as it was all that was available. It actually had better ratings than the previous (which doesn't say much). It's rated at 650CCA, 810CA, and 110 reserve capacity. However, I swear the battery isn't performing as well as the previous one. On top of this, the battery looked used. I questioned the guy on this when I purchased it, and he suggested it was just because it had been on the shelf for awhile. Stupid of me to trust him, eh?

I can't think of any difference that Canadian "model" battery would have if the other specifications are good or better. Did I just get a junk battery? If so, I will be making a fuss. Also, should I shoot for something rated higher if I return the thing? Any recommendations?

Thanks a bunch!

I can't remember, is reserve capacity same as Ah? It would make sense, I just want to verify that it is.

tditom May 19th, 2009 13:23

Quote:

Originally Posted by puter
I can't remember, is reserve capacity same as Ah?...

look here:
Quote:

Reserve Capacity (RC) or Amp Hour (AH) Capacity
Making a simple analogy between a water tank and a battery, the level in the tank will determine the water pressure (battery's voltage), but the diameter of the tank is going to determine the total volume of water (battery's Reserve Capacity or amp hour capacity). The size of the outlet will limit the discharge rate.
For car batteries, an equally important consideration to CCA is the Reserve Capacity (RC) or Amp Hour (AH) endurance ratings because of the effects of increased parasitic (ignition key off) loads while long term parking, power demands during short trips and emergencies. Endurance is defined by Eurobat as the actual combination of the energy content stored in a battery and the rate which the battery is discharged over the life time. RC is the number of minutes a fully charged battery at 80° F (26.7° C) can be discharged at a constant 25 amps until the voltage falls below 10.5 volts. European and Asian starting and deep cycle batteries are usually rated in Amp Hours (AH). To convert RC to AH (or AH to RC), check the battery manufacturer's capacity specifications. More RC (or AH) is better in every case. In a hot climate, if your car has a 360 OEM cold cranking amps requirement, then a 400 CCA rated battery with 120 minutes of RC and more electrolyte for cooling would be more desirable than one with 600 CCA with 90 minutes of RC. There is also a relationship between the weight of the battery and the amount of RC (or AH). The heavier the battery, the more lead is has and potentially a longer service life.
For deep cycle batteries, important considerations are will the Ampere-Hour (AH) rating meet or exceed the requirements based on your application? Peukert Effect? and how much weight you can carry? Most deep cycle batteries are normally rated in number of hours it take to discharge a fully charged battery to 10.5 volts in 20 hours at 80° F (26.7° C), denoted as "C/20". Discharge rates of 100 hours (C/100), 10 hours (C/10), 8 hours (C/8) or 6 hours (C/6) are also common ratings. When comparing amp hour capacities of deep cycle batteries, use the same discharge rating periods which can be obtained form the battery manufacturer. For example due to the Peukert Effect, the same wet deep cycle battery with the amp hour capacity of 240 discharged over 20 hours could have a capacity of 176 amp hours when discharged over six hours or 115 amp hours when discharged in one hour. Within a BCI Group Size, the battery with higher AH (or RC) will tend to larger in physical size, have longer service lives and weigh more because of thicker plates and more lead than car batteries.

NadaGasser November 28th, 2009 18:23

Walmart EverStart 94R Battery
 
Quote:

Originally Posted by ymz
I was going to say something about the original batteries having been German-built whereas the replacements are local products, but... the battery on my 2003 Jetta died before the battery on my 2001 Golf... and both of those were of German manufacture...

If you want a battery made in the Vaterland, go to Autolectra on Paré... (they aren't cheap, though...)

Yuri.

I visited my local Green Valley, AZ Super Walmart store today, and that store has begun stocking the Everstart MAX 94R battery, and the best part is ..... it costs only $75!

dqa November 30th, 2009 01:20

Quote:

Originally Posted by NadaGasser
I visited my local Green Valley, AZ Super Walmart store today, and that store has begun stocking the Everstart MAX 94R battery, and the best part is ..... it costs only $75!

I was really glad you wrote that, since I'd given up hope on Walmart after they discontinued their size 1N/1S batteries.

Unfortunately I was pressed for time, and couldn't make it to a Walmart with auto service before 5pm today. So on a hunch, I went by Sam's Club, which closed at 6. Sure enough, they also have 94R, in the Energizer. Unfortunately, I had to pay $10 more.

Here are the specs:
$75.00 Walmart Everstart Maxx (3yr free replacemt/9yr prorated warranty) 765CCA / 910CA

$84.66 Sam's Club Energizer (3yr free replacemt/8yr prorated warranty) 730CCA / 912CA

puter November 30th, 2009 06:29

Quote:

Originally Posted by dqa
Here are the specs:
$75.00 Walmart Everstart Maxx (3yr free replacemt/9yr prorated warranty) 765CCA / 910CA

$84.66 Sam's Club Energizer (3yr free replacemt/8yr prorated warranty) 730CCA / 912CA

What are the Ah ratings?

dqa November 30th, 2009 06:53

Quote:

Originally Posted by puter
What are the Ah ratings?

Neither battery lists that on the label. Everstart's phone number is 888-EVSTART, and it's made by Johnson Controls. Energizer doesn't list a phone number, but is also made by Johnson Controls.

puter November 30th, 2009 06:57

I guess what I was getting at is that the Ah rating is important and that you could be setting yourself up to replace that battery in 2 or 3 years rather than 6 or 7 years.

ymz November 30th, 2009 07:01

Quote:

Originally Posted by puter
you could be setting yourself up to replace that battery in 2 or 3 years...

At which point you get to play the "let's find that receipt and play the pro-rating percentage" game...

Yuri.

puter November 30th, 2009 07:42

Yup, and I really doubt that the Energizer battery comes even close to meeting spec.

NB_TDi November 30th, 2009 07:49

The Ah won't matter if you can't provide the proper CCA. Simple as that.

Ah = how long the battery will last with a load. How many Amps it can provide for an hour.

CCA = how many Amps it can dish out at 0c for 30 seconds.

They are not a function of each other, there is no magic formula. Those booster packs you find at stores that are 300-700 CCA or CA are usually about a 15-30Ah battery.

Again, Ah doesn't matter when it comes to starting your car.

pdreyfuss November 30th, 2009 09:16

I believe Amp-hr rating is important for starting in the cold, since the glowplugs have to be on a long time.

NB_TDi November 30th, 2009 09:44

They are not on for an hour. The only thing we as TDI owners should be looking at is CCA. Nothing else. Again. How do you think a 20Ah battery can boost a car? CA. Cranking Amps. This has nothing to do with the Ah rating of a battery. It has to do with the internal workings of the battery.

tditom November 30th, 2009 09:46

Quote:

Originally Posted by NB_TDi
The Ah won't matter if you can't provide the proper CCA. Simple as that.
...

Again, Ah doesn't matter when it comes to starting your car. Don't believe me? Go spend 6 years in EE school. I'm tired off all this misinformation about batteries.

Taken by itself, yes- CCA are what the starter needs to do its job.

The problem is that a battery that packs a lot of CCA punch (take an Optima for example), may not be able to sustain those CCA for repeated starts because of the healthy draw of the glow plugs just before every cold start. This is why a 72Ah minimum starter battery was spec'd for the tdi engine.

I would state it just the opposite of you: A starter battery with at least 72Ah will have enough CCA to start your tdi.

The issue is as simple as replacing the battery with the appropriate substitute (if one assumes that the electrical engineers employed by VAG know what they're doing ;)).

ymz November 30th, 2009 09:53

Quote:

Originally Posted by tditom
if one assumes that the electrical engineers employed by VAG know what they're doing .

Big assumption, if you've been involved with VWs for a long time... Historically, the electrical systems on VWs was always a source of much misery for the owners...

That said, I agree with you in thinking that NB_TDi is too focused on CCA... CCAs are needed for an initial start in frigid temperatures, but if one has several short drives in that type of weather, ones that don't warm up the engine enough or charge the battery enough, the reserve capacity in AH is more important...

My two pesos...

Yuri

NB_TDi November 30th, 2009 09:59

Then that is the fault of the driver. Not the battery. If your commute is so short that you are removing more power than putting in, you need a longer commute....or bike.

I'm not only saying CCA but CA. Which is just as important. If you plan on running a radio or TV with the car off for extended times you want a large Ah battery. You want your car to start? Largest CA you can find.

tditom November 30th, 2009 11:17

NB, let me ask you this:
Would you prefer a replacement battery for your tdi with 800 CCA and 50 Ah for $160 or one with 640 CCA and 80 Ah for $110?

ymz November 30th, 2009 11:26

Quote:

Originally Posted by NB_TDi
that is the fault of the driver. Not the battery.

Would you care to guess what type of driving goes on at a ski resort??? Wake up and drive 2 minutes for breakfast, back to the chalet, on to the slopes, back for lunch, back to the slopes, etc... repeat the next day... I can think of many similar scenarios...

Since these cars use geared starters, I'm not sure if they demand as much cold current as the old-time cars...

Y.

NB_TDi November 30th, 2009 11:33

Quote:

Originally Posted by ymz
Would you care to guess what type of driving goes on at a ski resort??? Wake up and drive 2 minutes for breakfast, back to the chalet, on to the slopes, back for lunch, back to the slopes, etc... repeat the next day... I can think of many similar scenarios...

Since these cars use geared starters, I'm not sure if they demand as much cold current as the old-time cars...

Y.

Maybe a pair of boots would suffice in that situation. :)

puter November 30th, 2009 12:49

NB: Do you really understand what CCA and Ah is? I'm not certain that you do.

You need to meet CCA for the car to start. Ah actually gives a value of HOW MUCH energy a battery can store.

If your battery cannot power the car overnight, plus the glow plugs, pluss the starter then it doesn't mattery what CCA it has because it won't have any juice left.

if you drain the battery too low during those starts (because it does not have the energy storage to do all this) you will have a battery that only lasts a couple of years because it keeps getting drained too far.

Stating that Ah represents "How many hours a battery can sustain a certain current" is very naive. The intent is not to tell how long it can sustain a certain current, it is to express how much energy the battery can store. You may be able to put out 3 amps for ten hours...but if you push 800 amps for 2 minutes (I just grabbed the CCA...I know this value isn't completely accurate) then you have used up just as much energy in 1/300th the time...not to mention the fact that the battery is not meant to be drained 100% and likely won't recover from that.

If you want to argue about this I can demonstrate the mathematical equations. If you want to research it yourself I recommend you look into "Ohm's law", "Dimensional analysis", and "Power (watts)".

I am not saying that CCA is unimportant, I am saying Ah is equally important.

NB_TDi November 30th, 2009 13:02

Interesting.

I do know what they all mean.

puter November 30th, 2009 13:14

Ah, I just have a BS in CE.

If you know all that, why are you seeming to indicate that the storage capacity of the battery is unimportant?

Both of the ratings are important, if you fall short on either one there will be negative consequences.

NB_TDi November 30th, 2009 13:22

I had a feeling you were into puters :p

All I'm trying to say is to START the car CA or CCA is needed. Obviously Ah is a requirement to operate but people are wooing over Ah ratings all the time. Once the engine starts, the battery is used for balance.

CA is not directly related to Ah though. I understand that a 10Ah battery can produce 20A for 1/2 an hour. But it's CA rating may not be 800A or so. This is due to the internal workings of the battery. You can't take a 2.2Ah double A battery and have it pump out 18A in 7 minutes. It would melt or....flux and go back to 1955 and meet it's mother! Okay granted we aren't talking about AA batteries but if the internal workings of a 80Ah battery isn't designed to put out 800A in a short burst, it may become damaged.

puter November 30th, 2009 13:32

I completely agree. CCA largely (believe) is dependent on internal resistance as a function of temperature.

That being said, I actually don't agree on people wooing over Ah. From what I have seen, for the most part people completely disregard Ah. That's why I always ask about Ah when people recommend a new battery. You're very right that without the correct CCA the car won't start...but if your Ah is too low then you'll just end up buying a battery in two years because you're over draining it.

My whole point is that CCA and Ah should be viewed as equally important. Do you really feel the people buying the Energizer battery that meets CCA but may or may not meet Ah are saving money? My guess is that they'll end up buying two or three times the number of batteries as those who buy one who meets spec...and think that their saving money because they're paying $75 rather than $140. In reality there's a good chance they are spending more simply because they have to buy more of the batteries.


In short, you're right...CCA IS important...but so is Ah. Everyone seems to ignore Ah and when I ask "what is the Ah" rating roughly 80-90% of the time I get either "I dunno" or "what's Ah?" followed closely by someone arguing that Ah doesn't matter and only CCA matters.

tditom November 30th, 2009 13:37

Quote:

Originally Posted by NB_TDi
...if the internal workings of a 80Ah battery isn't designed to put out 800A in a short burst, it may become damaged.

where do you come up with this requirement?

The OE battery for the tdi is spec'd for 640 CCA (SAE), and either 72 or 80Ah. You can bet that the actual demand from a properly working starter is something much lower than 640A. I believe Drivbiwire has measured this, or has the data from someone who has measured it.

NB_TDi, can you answer the question about your choice of battery from my last post?

NB_TDi November 30th, 2009 13:52

It's not a requirement it's numbers I pulled from the air. Sorry I missed your post about the choice of batteries. Since I'm a penny pincher, I'd probably take the cheaper :p

puter, I'll agree with that. Ah is important. I didn't mean to make it sound like it's not important at all. For that I'm sorry. :)

puter November 30th, 2009 13:55

No need to apologize. I just didn't want some newbie to come to this thread and go "oh, all I have to do is make sure it meets spec for CCA and I'm all good" and go buy a $60 dollar battery...3 times in 7 years :)

I understand the penny pinching...but it seems short sighted to me. In the long run I'd guess that you'd end up spending more money if you get a battery that doesn't meet spec for Ah.

T_D_I_POWER December 11th, 2009 07:42

Size for size SAE spec battery wins handily over Ah DIN/EN spec EU battery

Size for size comparison

A 20-year old study still holds true

OE battery 640 CCA. Warranty 1-Year free replacement 5-Year prorated.

http://pics.tdiclub.com/data/500/med...tery_label.JPG
Picture provided by koyaajerms


OEM battery 730 CCA. Warranty 3-Year free replacement 8-Year prorated

http://farm5.static.flickr.com/4037/...88a02350_b.jpg
Picture provided by tango_28

pdreyfuss December 11th, 2009 15:20

Where can you buy the Energizer battery? Maybe its amp-hour or reserve capacity is less than the OEM battery's. I think it's somewhat unfair to leave that spec out of the comparison.

T_D_I_POWER December 11th, 2009 19:01

That's not for my car, but tango_28 bought it @ Sam's for $80 for his car.

The casings are identical, but internally the two are totally different batteries. SAE specs battery has lower internal resistance, hence higher CCA. On the other hand, DIN/EN specs battery has higher internal resistance, lower CCA.

OEM SAE std battery specs out CA & CCA. While, OE DIN/Ah spec battery specs out Ah & CCA.

What kind of spec are you looking for?

10then34 December 15th, 2009 18:58

My '06 is starting to have hard-starts when left at the airport for 3 days in -15F weather. Part of this is undoubtedly the DSG goo being frozen, but I noticed that after a couple of starting attempts, the cranking speed starts to deteriorate. This battery has seen a couple of rough winters, so I don't have a problem replacing it before it leaves me stranded.

From what I could gather out of this thread and the interstate website, I would need a '94R' battery. One of the types that has come up is the
MTP-H7 marketed by Interstate batteries.

Anyone with experience using this battery ?

puter December 15th, 2009 19:24

Quote:

Originally Posted by T_D_I_POWER
OEM SAE std battery specs out CA & CCA. While, OE DIN/Ah spec battery specs out Ah & CCA.

What kind of spec are you looking for?

I really don't see how this is helpful. CA/CCA and Ah are measuring completely different things.

I don't care if one doesn't spec out Ah, you still need to meet the spec for Ah. I also don't care if the spec for the battery isn't written out on the battery, the car has Ah requirements and you need to meet those. Now, the OEM I am sure meets those, it just may not indicate what the values are (I have not verified this, this is based upon your post).

And before someone goes off again, no, I am NOT saying Ah is more important than CCA. don't put words into my mouth. I am saying it is equally important. (I put this qualifier in because I have been accused of saying the above multiple times when I have not said it).

puter December 15th, 2009 19:26

Quote:

Originally Posted by 10then34
From what I could gather out of this thread and the interstate website, I would need a '94R' battery. One of the types that has come up is the
MTP-H7 marketed by Interstate batteries.

Anyone with experience using this battery ?

The OEM battery is competitively priced and a great battery. If you don't want to buy from the dealership (I don't blame you) then the Interstate MTP-H7 is also a great battery and priced about the same as the OEM one.

TornadoRed December 15th, 2009 19:39

http://www.interstatebatteries.com/c...nths+-+640+CCA

I don't know, does it have 640 CCA or 880 CCA? Both numbers are posted. And it seems kind of expensive, even with a huge discount off of the recommended price.

davebugs January 10th, 2010 13:49

Question about battery replacement.

Do I need to have the cigarette lighter plugged into a jump box or one of those things that takes a 9v battery? I have 3 of the darn things and can't find a one of them.

Windows are up, car is unlocked, key is outside the car.

Other than trying to remember how/if the 2 little tabs in the back that let the top plastic piece (with the fuses) swivel I'm about ready. I figure what to do with those 2 tabs wil become more apparent after the positive terminal is off.

I'm mostly concerned about the alarm. Radio I can reset, Sirius I can reset if necessary.

I searched through many battery threads and saw the windows and radio mentioned but not the alarm.

I'm off to look for a procedure w/pics to see about these little tabs and how they work. So far the threads I've found the pic links don't work.

Edit: found a pic where someone just bungee'd it - works for me. Now how about that alarm? 2001 Golf TDI.

mk3 January 10th, 2010 14:26

I've got an 03 with the 5-speed and aftermarket radio. I just went in and replaced the battery with no special precautions. The only thing I can think of that you would normally do is make sure you have the radio code... however I have an idea that may not even be necessary on some cars.

I got the OEM battery from Hall in Brookfield, WI for $110+tax. I could not find a better price for the appropriate 94R 80 Ah battery.

davebugs January 11th, 2010 15:32

I ended up going with OEM. List just over 100 bucks.

My local Wal-Mart wanted to sell me a MAXX that didn't have the CCA's the stock one had. And were clueless about AMP hours.

My Titanium from Advance lasted 4 years.

I ended up being able to borrow a cigarette lighter Male/Male so I didn't have to reset anything.

Useful thread.

MOGolf January 11th, 2010 15:52

To add this "definitive" thread...

You can get a higher Ah battery from VW that fits. It is the same physical size as the 80Ah AG/DH. This is the 85Ah DJ (replaces the AJ).
http://pics.tdiclub.com/data/3769/me...Ah_battery.jpg

I put this one in my 04 Passat.

T_D_I_POWER January 12th, 2010 17:00

This battery doesn't have the gas vent tube? Or is it at a different location and is not clearly shown in the picture?

MOGolf January 12th, 2010 19:39

The vent is just like the 80Ah battery. That picture was taken before install. Look closely and you'll see the vent plug on the + side. It was moved to the - side upon install into my Passat and the tube attached on the + side.

T_D_I_POWER January 13th, 2010 08:29

Thanks, I see it now. I have forgotten that the OE battery gas vent tube is collected from the + side as oppose to the OEM Energizer E48, which is collected in the middle front side between the two posts

snakeye December 11th, 2010 14:41

Quote:

Originally Posted by TornadoRed (Post 2798127)

Winter's coming around again, time to bump this good old thread. :D

I'm looking at that battery; my question is what's the Ah rating? :confused:

Any other good suggestions? It's very hard to research info on batteries cause there are so many people saying things like "I bought this Optima battery, it's 100000000 CCA and has been going strong since I bought it yesterday".

Any suggestions on a good battery that will last a long time and won't give me any problems starting my car in -35 celcius? I'm thinking of going to the dealer and getting an OEM one, or finding one that's equivalent.

OlyTDI December 11th, 2010 15:04

Yeah, get an OEM battery. They're reasonably priced, designed for the car and work well.

TornadoRed December 11th, 2010 15:56

Quote:

Originally Posted by snakeye (Post 3213894)
Winter's coming around again, time to bump this good old thread. :D

I'm looking at that battery; my question is what's the Ah rating? :confused:

Any other good suggestions? It's very hard to research info on batteries cause there are so many people saying things like "I bought this Optima battery, it's 100000000 CCA and has been going strong since I bought it yesterday".

Any suggestions on a good battery that will last a long time and won't give me any problems starting my car in -35 celcius? I'm thinking of going to the dealer and getting an OEM one, or finding one that's equivalent.

I'm still recommending the Everstart MAXX 94R from Walmart for around $75-80. It has excellent cold-cranking amps numbers, a very good warranty, and if you need a warranty replacement you'll never have to travel very far. It may not be the very best battery, but it could be the best battery for the price.

snakeye December 11th, 2010 16:14

Quote:

Originally Posted by TornadoRed (Post 3213961)
I'm still recommending the Everstart MAXX 94R from Walmart for around $75-80. It has excellent cold-cranking amps numbers, a very good warranty, and if you need a warranty replacement you'll never have to travel very far. It may not be the very best battery, but it could be the best battery for the price.

What are the specs of that battery? Can't find any info anywhere.

I'm looking for a good one, and am wiling to spend a bit over 100. So far the Interstate one looks good, it has a crazy warranty. I think I read somewhere that they actually made OEM batteries on some TDI models.

Jetiwarrior December 11th, 2010 17:11

The Everstart MAXX 94R that I bought one year ago from Walmart says 910 amps cranking at 32*F and CCA is 765. It works fine in my 03 Jetta but then it never get colder than the high 20's during a severe cold spell. Batteries usually die out here in the summer when it gets into the 110's*F. Check with your Walmart because they usually make several models of the same battery for different regions of the country.

TornadoRed December 11th, 2010 18:13

Quote:

Originally Posted by snakeye (Post 3213974)
What are the specs of that battery? Can't find any info anywhere.

I'm looking for a good one, and am wiling to spend a bit over 100. So far the Interstate one looks good, it has a crazy warranty. I think I read somewhere that they actually made OEM batteries on some TDI models.


Some of the Everstart MAXX 94R batteries are made by Exide, but most are made by Johnson Controls, I think. 910 cranking amps, 765 cold cranking amps. Used to have a 3-year full-replacement warranty and 9-year pro-rated warranty, but I think they've dropped the pro-rated warranty.

snakeye December 11th, 2010 18:31

What about ampere hours?

Jack Frost December 11th, 2010 18:41

Ampere hours do not matter to us Canadians, unless you intend to use the battery drive your fishing motor, or wheel chair. It is cold cranking amps that you need to look for for starting a car in cold weather.

snakeye December 11th, 2010 18:50

Quote:

Originally Posted by Jack Frost (Post 3214112)
Ampere hours do not matter to us Canadians, unless you intend to use the battery drive your fishing motor, or wheel chair. It is cold cranking amps that you need to look for for starting a car in cold weather.

Right so I should be OK with a 40Ah battery when VW recommends 80? :confused:


Again...

Quote:

Originally Posted by snakeye (Post 3213894)
It's very hard to research info on batteries cause there are so many people saying things like "I bought this Optima battery, it's 100000000 CCA and has been going strong since I bought it yesterday".

Isn't the OEM battery for our cars 640 CCA or something? If so, and it starts fine, then why go out and buy one with a higher CCA but less Ah than what VW recommends?

Jack Frost December 11th, 2010 19:18

You can if you want so long as it fits. I don't know what VW recommends as a minimal AH. In colder climates, that figures is not important.

In cold climates, what limits a battery is its CCA. Not its AH. In warmer climates, the reverse is more valid. What VW recommends is a battery that physically fits where they designed it to go, has its terminals located in the right places and is suitable for everyone. If you live in a colder climate and can find another battery that fits and has the same CCA as the original, you will have equivalent cranking power on a cold day when you need it.

However, too much CCA is not good. If the battery is over matched, then you can burn out your starter unless you have the good sense to allow it to cool down after 30 seconds of cranking.

To make life complicated, there are many other things about a battery other than its size and its capacity. The exact alloy used in the battery plates, the thickness of the plates and many other factors that go into its construction can affect how long and reliable that battery will be. Generally, an OEM battery is built well and will withstand vibrations and a discharged state very well. There are batteries out there that have good CCA and AH but their plates get sulfated in a discharge state or they break under the vibrations of the car chassis.

snakeye December 11th, 2010 19:27

Quote:

Originally Posted by Jack Frost (Post 3214153)
However, too much CCA is not good. If the battery is over matched, then you can burn out your starter unless you have the good sense to allow it to cool down after 30 seconds of cranking.

Why would you need to crank the engine that long with a batter that has a good CCA to begin with? :D

I think Ah definitely DOES matter in cold weather, considering the use of glow plugs, heated seats, window defroster, heated mirrors, etc. Not a problem if you do long trips, but what if you're doing short trips with a lot of cranking?

Jack Frost December 11th, 2010 19:46

In the old days of flooded carburetors, drivers cranked their engines a lot more than they do now. But an old engine with a lot of its compression lost might still require a lot of cranking to get it started. Like some of us get "cranky" in the morning before our coffee.:D

I agree that glow plugs depend more on AH than CCA. However, when they stop glowing and it is time to turn on the starter, the ability of the battery to continuously delivery several hundreds of amperes to the starter is much more important than its abilty to deliver a dozen amperes over an hour or two. When it is cold, your battery has only half of its ability to deliver ampereres. That is also the time, you really need them. So why care about AH; which by the way is measured at room temperature in Florida; not at minus something below freezing in Manitoba where CCA rules.

snakeye December 11th, 2010 19:58

Which makes it that much more important to get a good Ah battery! Anyway I read in another thread that VW's requirements are 590 CCA and 80 Ah. I'm pretty sure the CCA will be above that on most 80 Ah + batteries, which is what I'm looking for. Besides, what's the point of having that much CCA? It's like boosting the cetane of your car to a uselessly high level. If the car starts fine with 590 CCA, why get 750, especially at the expense of Ah?

Btw a battery with a lower Ah will discharge quicker right? So if you have a low Ah and put extra stress on the battery in cold weather while doing short trips, wouldn't you be more likely to discharge it and have a harder time starting your car than say if you have double the Ah rating and maybe a bit lower CCA that's still over VW's minimum recommendation?

Jack Frost December 11th, 2010 20:18

Quote:

Originally Posted by snakeye (Post 3214190)

Btw a battery with a lower Ah will discharge quicker right?

You are starting to compare sprinters with marathoners. A battery with a lower AH (but a high CCA) may last longer in a starting situation because it is designed with thinner plates to deliver high amperages for short periods of time and was never intended to deliver low amperages for long periods of time. One would never put a motor designed for driving wheel chairs and trolling motors in a car no matter how many Ah it has. Unless of course, you need your car battery to keep the seats warm when you park with your girl friend at a drive-in movie. ;) Then by all means, go to the nearest store and buy a marine deep cycle motor. When you see in on the shelf, it has a humongous AH and you will notice that it is not rated for CCA. That is because it is not designed for that. It's design is optimized with high AH under long and low amperage draws. It will also start you car for a few times, but not many in cold weather. Neither will it last long.

puter December 11th, 2010 20:43

Quote:

Originally Posted by Jack Frost (Post 3214203)
You are starting to compare sprinters with marathoners. A battery with a lower AH (but a high CCA) may last longer in a starting situation because it is designed with thinner plates to deliver high amperages for short periods of time and was never intended to deliver low amperages for long periods of time. One would never put a motor designed for driving wheel chairs and trolling motors in a car no matter how many Ah it has. Unless of course, you need your car battery to keep the seats warm when you park with your girl friend at a drive-in movie. ;) Then by all means, go to the nearest store and buy a marine deep cycle motor. When you see in on the shelf, it has a humongous AH and you will notice that it is not rated for CCA. That is because it is not designed for that. It's design is optimized with high AH under long and low amperage draws. It will also start you car for a few times, but not many in cold weather. Neither will it last long.

Your battery should meet spec for both Ah and CCA. If it does not meet spec for Ah then you will not have enough power to run all the electrical overnight, run the glowplugs, and then turn over the motor without draining the battery too far and shortening life.

If you do not meet spec for CCA then you will not be able to supply the current in cold weather to turn the engine over fast enough to generate the compression and RPM that you need to start.

In short, BOTH specs are important.

Jack Frost December 11th, 2010 20:56

Quote:

Originally Posted by puter (Post 3214225)

In short, BOTH specs are important.

I agree, but when it is -35 C in the morning and you livlehood depends on your car's ability to start, then CCA is very important. That being said, more than what you need for that kind of morning is over kill.

tditom December 11th, 2010 22:39

Quote:

Originally Posted by Jack Frost (Post 3214153)
You can if you want so long as it fits. I don't know what VW recommends as a minimal AH. In colder climates, that figures is not important.

In cold climates, what limits a battery is its CCA. Not its AH. In warmer climates, the reverse is more valid. What VW recommends is a battery that physically fits where they designed it to go, has its terminals located in the right places and is suitable for everyone. If you live in a colder climate and can find another battery that fits and has the same CCA as the original, you will have equivalent cranking power on a cold day when you need it.

However, too much CCA is not good. If the battery is over matched, then you can burn out your starter unless you have the good sense to allow it to cool down after 30 seconds of cranking.....

wrong. Ah is very important for a diesel. The tdi has a 80 Ah battery (much more Ah than spec'd for gasser engines) from the factory for a reason. The ability of the battery to provide juice to the glow plugs before engaging the starter could make the difference between the battery being able to start the engine or not. Especially the 100th time the battery is used to start the car.

The statement about too many CCA being a problem is also wrong. CCA rating for a battery indicates how many amps it can provide under certain conditions. The starter design determines how much current is demanded from the battery. So if a starter demands 400 A it makes no difference if its pulling it from a battery that can provide 700 or 1000 CCA. You're not going to "burn out" the starter.

The battery demands what it needs from the alternator for recharging when the engine is running on its own, so the time it takes to recharge is dependant on how low the battery was discharged. This is another reason why Ah outweighs CCA rating- it has the ability to sustain "engine off" loads without being discharged too deeply.

Bottom line is that if you find a starter battery with 80 Ah, then you will have plenty of CCA to do the job. In the case of an A4 chassis tdi, any 94R battery should work fine. Don't go out and buy an Optima just because it can provide 1000 CCA- note that it is only able to provide 50Ah. You'll also pay about 50% more for excessive CCA rating and insufficient Ah...

snakeye December 12th, 2010 00:01

Since we're in the battery thread... could a weak battery cause the heated seats to occasionally not heat up properly?

pdreyfuss December 12th, 2010 04:05

Quote:

Originally Posted by snakeye (Post 3214317)
Since we're in the battery thread... could a weak battery cause the heated seats to occasionally not heat up properly?

If so every other thing would have low voltage along with the seats. Are your headlights OK while your seats aren't working?

snakeye December 12th, 2010 04:21

Quote:

Originally Posted by pdreyfuss (Post 3214362)
If so every other thing would have low voltage along with the seats. Are your headlights OK while your seats aren't working?

Yeah the headlights are ok, high beams as well.

Jack Frost December 12th, 2010 04:59

Quote:

Originally Posted by tditom (Post 3214300)
You're not going to "burn out" the starter.

Actually I know people who have. It might not ever happen in Texas, but given a real cold day here when engines don't like to start and batteries run themselves trying to turn over motors that just won't catch, a friend of mine resolved the problem by putting in a brand new and bigger battery and fried his starter motor because of excessive cranking. He didn't fry it on his older battery because it discharged before the starter motor over heated.

I am not advocating that we put batteries intended for bulldozers and tractors into our TDI just to get the CCA as high as possible. What I am saying that in colder climates CCA is an important feature to look for. You can put into your car a battery with very high Ah and no CCA, and it will work a few times. But it will never last a winter here. The plates would buckle from the discharge rates related to starting and subsequent charging conditions it was not designed for.

In climates such as Texas, CCA would not be an issue. Your batteries still have 65% of their capacity in the winter and motors only need 155% more cranking power. In climates that are in between Texas and Montreal and Canada, cranking amps is a good feature to look for.

But for the temperatures that snakeye and myself deal with, CCA matters most (provided the battery fits its compartment). In our winters, batteries only have 20% of their capacity and car motors need 350% more cranking power. How are ampere hours going to help us? Ah and warm glow plugs are useless if a -35 C battery cannot deliver a sustained rate of hundreds of amps for 30 seconds that may be required to turn over a stiff motor. What a battery can do after 30 seconds and up to an hour is irrelevant, because the windings in the starter motor are fried.

BTW, I found this interesting image from this link http://www.speedace.info/car_batteries.htm

http://www.speedace.info/speedace_im...e_capacity.jpg

puter December 12th, 2010 09:45

Jack: getting a battery with higher CCA is fine, so long as the battery ALSO has at least 80Ah.

If the battery does not have the storage capacity then a high CCA will do no good because there will not be enough energy stored to start the engine.

Jack Frost December 12th, 2010 11:10

Agreed. You need both. More of one than the other depending on your climate. As it has already been mentioned, CCA will not help glow plugs. Neither will CCA help powering the car's electronics which consume 2.4 amp hours every day it is not used. That is 16.8 Ah for a whole week. For a 80 Ah battery, that is about 20% of its capacity. Enough to damage it. And we haven't used the glow plugs yet.

I wouldn't be surprised that car manufacturers will be building cars with two type of batteries. One designed to start the car and another to power the electronics and glow plugs when the car isn't running. One cannot have a single battery do both jobs without one feature becoming too strong and the other compromised.

NB_TDi December 12th, 2010 11:58

Quote:

Originally Posted by Jack Frost (Post 3214734)
Agreed. You need both. More of one than the other depending on your climate. As it has already been mentioned, CCA will not help glow plugs. Neither will CCA help powering the car's electronics which consume 2.4 amp hours every day it is not used. That is 16.8 Ah for a whole week. For a 80 Ah battery, that is about 20% of its capacity. Enough to damage it. And we haven't used the glow plugs yet.

I wouldn't be surprised that car manufacturers will be building cars with two type of batteries. One designed to start the car and another to power the electronics and glow plugs when the car isn't running. One cannot have a single battery do both jobs without one feature becoming too strong and the other compromised.

You're kinda all over the place there with your units. You can't use 2.4 Ah in a day. It's a time AND current measurement already.

If you use 2.4A in 24H then you're actually consuming 100mAh.

pdreyfuss December 12th, 2010 12:10

Quote:

Originally Posted by NB_TDi (Post 3214777)
You're kinda all over the place there with your units. You can't use 2.4 Ah in a day. It's a time AND current measurement already.

If you use 2.4A in 24H then you're actually consuming 100mAh.

I don't see any problem with the units - Jack assumes or knows that the car draws .1A while sitting idle. For one day: .1A * 24 hr = 2.4Ah.

NB_TDi December 12th, 2010 12:12

Quote:

Originally Posted by pdreyfuss (Post 3214784)
I don't see any problem with the units - Jack assumes or knows that the car draws .1A while sitting idle. For one day: .1A * 24 hr = 2.4Ah.

No. Incorrect.

Ah means how much power is drawn in a single hour. Not 24. Trust me, I posses a masters in EE. ;)

pdreyfuss December 12th, 2010 12:35

Quote:

Originally Posted by pdreyfuss (Post 3214784)
I don't see any problem with the units - Jack assumes or knows that the car draws .1A while sitting idle. For one day: .1A * 24 hr = 2.4Ah.

I still disagree: drawing .1A for an hour - .1A * 1hr = .1 A*hr (a certain amount of electric charge). If the same current is drawn for a day it's .1A * 24hr = 2.4 A*hr (24 times that charge).

A*hr is defined for one hour, but doesn't have to be used for only one hour - if a battery is rated at 80A*hr, it will supply 80A for an hour, but it will also supply 40A for two hours, or 3.333A for 24 hours.

NB_TDi December 12th, 2010 12:47

The unit as it stands is for a single hour. By your logic if I had no previous knowledge of this discussion and you said 2.4Ah. I would then calucate that in 24hrs it would use 57.6A in a whole day.

Which is just plain wrong.

The unit is to advise users that the unit can put out X amount of current. A 50Ah battery is able to supply 50A for a single hour. You can say that it supplies 100A for 30 minutes, but you can't say it supplies 50Ah for a day. Doesn't work like that.

Jack Frost December 12th, 2010 13:15

Quote:

Originally Posted by NB_TDi (Post 3214787)
No. Incorrect.

Ah means how much power is drawn in a single hour.

With all due respect, amperes is not a unit of power. It is a unit expressing the flow of electrons. To express electrical power, you need voltage and time as well as amperes. ;)

NB_TDi December 12th, 2010 13:18

Yes, you're correct, but my point is an Ah is one hour. You cannot just decide that it's 24hrs. It doesn't work like that.

If that was the case I'd change a work week to 1 day. :)

pdreyfuss December 12th, 2010 13:18

Quote:

Originally Posted by NB_TDi (Post 3214831)
The unit as it stands is for a single hour. By your logic if I had no previous knowledge of this discussion and you said 2.4Ah. I would then calucate that in 24hrs it would use 57.6A in a whole day.

Which is just plain wrong.

The unit is to advise users that the unit can put out X amount of current. A 50Ah battery is able to supply 50A for a single hour. You can say that it supplies 100A for 30 minutes, but you can't say it supplies 50Ah for a day. Doesn't work like that.

There are other units like this kilowatt-hours, foot-pounds, for example. I never heard of anyone saying kilowatt-hour was only usable for one hour or foot-pounds for one pound. There is nothing so unique about A-h that makes it usable for only one hour. A unit is a unit, and can have any number beside it - still disagree.

lovemybug December 12th, 2010 13:20

Quote:

Originally Posted by snakeye (Post 3214317)
Since we're in the battery thread... could a weak battery cause the heated seats to occasionally not heat up properly?

I've had an old battery be the root cause of a few CELs before. Toward the end of my battery's life, I was getting occasional CELs for a speed sensor error. I've never touched the sensor, and have not had any CELs for that since the new battery went in. BTW, I got the OE battery from the dealer because I knew for certain that it would fit.

NB_TDi December 12th, 2010 13:33

Quote:

Originally Posted by pdreyfuss (Post 3214853)
There are other units like this kilowatt-hours, foot-pounds, for example. I never heard of anyone saying kilowatt-hour was only usable for one hour or foot-pounds for one pound. There is nothing so unique about A-h that makes it usable for only one hour. A unit is a unit, and can have any number beside it - still disagree.


The 'h' in Ah, stands for hour. As in 360 seconds, 60 minutes. You know....an hour... ;)

snakeye December 12th, 2010 13:37

Quote:

Originally Posted by lovemybug (Post 3214855)
I've had an old battery be the root cause of a few CELs before. Toward the end of my battery's life, I was getting occasional CELs for a speed sensor error. I've never touched the sensor, and have not had any CELs for that since the new battery went in. BTW, I got the OE battery from the dealer because I knew for certain that it would fit.

Yeah I'm going to call the dealer tomorrow. If their battery is reasonably priced then I'll buy one from them. I've read many people here have had their OEM battery last over 6 years. Since I'm pretty sure the cars that VW sells here DO start in -35, I think an OEM battery is a safe bet.

pdreyfuss December 12th, 2010 13:52

Quote:

Originally Posted by NB_TDi (Post 3214866)
The 'h' in Ah, stands for hour. As in 360 seconds, 60 minutes. You know....an hour... ;)

2.4 A*hr is an amount of electical charge equal to 2.4A flowing for one hour or .1A flowing for 24 hours. Either way it's the same charge.

NB_TDi December 12th, 2010 14:59

Quote:

Originally Posted by pdreyfuss (Post 3214885)
2.4 A*hr is an amount of electical charge equal to 2.4A flowing for one hour or .1A flowing for 24 hours. Either way it's the same charge.

It's NOT!

The unit of Ah only applies to a single hour!! The correct measurement is 100mAh. Period.

pdreyfuss December 12th, 2010 15:17

Quote:

Originally Posted by NB_TDi (Post 3214965)
It's NOT!

The unit of Ah only applies to a single hour!! The correct measurement is 100mAh. Period.

From Wikipedia: "One ampere-hour is equal to 3,600 coulombs (ampere-seconds)"

It's just a certain amount of charge, defined in a way that uses an hour. That charge can equal more current for less time or less current for more time.

If a battery is rated at 80 A*hr, it can supply 80A for an hour or 40A for two hours. So if a battery can supply 40A for two hours, doesn't that make it an 80A*hr battery?


All times are GMT -7. The time now is 10:56.

Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright - TDIClub Online LTD - 2014

Page generated in 0.15917 seconds with 7 queries
[Output: 124.90 Kb. compressed to 118.96 Kb. by saving 5.94 Kb. (4.75%)]