How high to fill OEM battery?

[POWERSTROKE]

Where is the full mark for the OEM battery when adding distilled water?

[pdq import repair]

Today's batteries are not at all like the old ones. If the battery has consumed water it is due to boiling it off due to heat, commonly caused by internal shorting.
If the battery even has caps and you fill it, it will cook out the water and acid and melt the car in that area.
Best to replace a battery when it starts using water.

[joetdi]

You want the plates covered but. below the inner ring par of the battery if it has one. 3/8 of an inch over the plates should be ok. Are you sure you don't need a battery

[Mongler98]

If your replacing the water, don’t. Do a flush on the battery instead and a recharge. In a nut shell, get a glass or proper plastic rated container for the acid, drain, and then fill with distilled, drain again and bring the acid to a proper disposal after neutralizing it with baking soda or chalk and a PH test. Now fill up the battery with baking soda and distilled water, about 2 cups of baking soda. Now let it sit overnight. Now drain and flush again 2 times with distilled and then drain again. Now fill with new acid or acid water mix and charge at 2 amps overnight with a smart charger or a regular charger but check the votes every few 2 hours, don’t let it go 12.9volts. You’re done. This might buy you a few years and only costs about $15 bucks.

What pdq imports is saying is true. Sulfates build up and eventually short it out. By doing this rinse you can break them down and correct it if the battery is not too bad. I have had moderate success with this and would recommend it if you have a battery you can fill up that is old and don’t have the $$$ for a new battery. The issue is that the CCA changes a lot. Say you have a 650cca battery that was 10 years old and you did this to it, it would probably drop to 400cca. You can test this by pulling the amp reading from the battery when it’s cold out and trying to start a cold engine. You should see no less than 10 volts when cranking.

Fully charged cold car, run headlights for 2 minutes then turn them off. Now crank it with the volt meter set to dc volts. Then do it again but this time use the amp meter clip. You should see an amp draw to the starter. Now you have an amp draw at a voltage output. It’s nearly impossible to calculate the real CCA this way without a tester that does this for you but a rule of thumb is that after 1 minute of cranking (take the fuel relay out to crank it) you should only drop 0.2 to 0.4 volts and the voltage on the battery only drops by 0.4 volts at most and regains this voltage back to the 12.8 or whatever it was before the crank, within 5 minutes of rest. This is very back yard science on measuring the cca power of the battery but it’s good enough for 3 years of life for $15 bucks. You can also take it to AutoZone or advanced auto and have them test the battery for you. We do these now vs what I just mentioned but when you’re not close to a shop and this are what you have on hand, it works.

[flee]

BTW, charging voltage for a standard, flooded lead-acid is 13.7 VDC.
Before you put on the rubber gloves and face shield, add enough distilled to
cover the plates and then fast idle until the voltage is stable. Use VCDS or a VOM.
Up to 14.4v. is OK but if it's much higher you may need a regulator not a battery.

[volmaniac]

From NarfBLAST:

Originally Posted by NarfBLAST

Here is a battery I bought from VW a few years ago, it has actual marks for the fluid and the case is translucent so you can see the fluid level in these pictures. This battery has obviously been abused and poorly maintained, and may be too far gone to hold a charge again. It was in 2001 Golf that has been in storage for over a year.



I used a black marker to highlight the marks:



I did have to remove stickers to find the fill caps. Also, someone was asking "what are split rings" I guess those are the black half moon things you see down the fill holes?

Before filling I could see plates and acid and white plastic down the holes. After filling I could see nothing but the black fill tubes and water touching the half moon things at the bottom of the fill tubes. So I guess you could say "fill to the bottom of the fill tubes"? I forgot to take a picture before filling and my after picture just shows a black hole so all I can say is, "You will know what I mean when you see it."

[jettawreck]

Originally Posted by Mongler98

If your replacing the water, don’t. Do a flush on the battery instead and a recharge. In a nut shell, get a glass or proper plastic rated container for the acid, drain, and then fill with distilled, drain again and bring the acid to a proper disposal after neutralizing it with baking soda or chalk and a PH test. Now fill up the battery with baking soda and distilled water, about 2 cups of baking soda. Now let it sit overnight. Now drain and flush again 2 times with distilled and then drain again. Now fill with new acid or acid water mix and charge at 2 amps overnight with a smart charger or a regular charger but check the votes every few 2 hours, don’t let it go 12.9volts. You’re done. This might buy you a few years and only costs about $15 bucks.

What pdq imports is saying is true. Sulfates build up and eventually short it out. By doing this rinse you can break them down and correct it if the battery is not too bad. I have had moderate success with this and would recommend it if you have a battery you can fill up that is old and don’t have the $$$ for a new battery. The issue is that the CCA changes a lot. Say you have a 650cca battery that was 10 years old and you did this to it, it would probably drop to 400cca. You can test this by pulling the amp reading from the battery when it’s cold out and trying to start a cold engine. You should see no less than 10 volts when cranking.

Fully charged cold car, run headlights for 2 minutes then turn them off. Now crank it with the volt meter set to dc volts. Then do it again but this time use the amp meter clip. You should see an amp draw to the starter. Now you have an amp draw at a voltage output. It’s nearly impossible to calculate the real CCA this way without a tester that does this for you but a rule of thumb is that after 1 minute of cranking (take the fuel relay out to crank it) you should only drop 0.2 to 0.4 volts and the voltage on the battery only drops by 0.4 volts at most and regains this voltage back to the 12.8 or whatever it was before the crank, within 5 minutes of rest. This is very back yard science on measuring the cca power of the battery but it’s good enough for 3 years of life for $15 bucks. You can also take it to AutoZone or advanced auto and have them test the battery for you. We do these now vs what I just mentioned but when you’re not close to a shop and this are what you have on hand, it works.

I would rather pay $100 for a new battery than go thru all that and then still have a very marginal battery.