Power Inverter?

Hello,
There are no generators available out here with the hurricance coming, and I wanted to know what kind of power inverter our Jettas can handle. Please respond ASAP, as I'd like to buy it today, but I don't want to damage the Jetta or our appliances. I want to run my fridge, freezer, and maybe my private well pump, off my battery with the engine running. So it looks like I need 1500 watts or more based on the calculations you guys gave me from other posts. Thank you!

Sincerely,

Im not an expert but 1500 is not enough to power a what you are asking. Check out http://www.usa-generator.com/info/load_cht1.htm and http://www.oksolar.com/technical/consumption.html
When the compressors on the refrig and freezer kick in you get a serge. I would bet on a 1500 watt inverter you probably could could not run any one of those items.

As for hurting your vehicle, if connecting directly connecting to the battery the circuit protector on the inverter should kick off because it can not provide the power needed.

Okay. So I would venture 5000 W would be enough. Can the Jetta sustain that, With the motor running and connected to the battery?

Yep should be fine.

1500 Watt is too small. Probably a 5000 Watt isn't big enough. I have a 1500 Watt the best it will do is a drill or TV. A hair dryer pulls too much wattage for a 1500 Watt. The ones at Harbor Frieght are not full sine wave so you lose current in the process. You need a generator for home appliances. I've not used the Harbor Frieght generators, but for just emergency purposes it seems they would be fine. In the area I live in we have AEP power and two years ago we had an ice storm that dropped a lot of their temporary lines. Our whole city block was without power for a week. So my neighbors have them, I got by because I had relatives that had power, We hauled everything out of our deep Freezer and refrigerator and took it them. I'm total electric we had to rent a motel room as well. Good luck, stay safe. Vent that generator if you purchase one or can find one. We had a couple people that got carbon monoxide poisoning do to them running them in their garages with even the doors half open. It's best to run one on the outside wall of your house and run an extension cord through a window. (Your best bet is the biggest invertor you can get.) The more items you have on it the faster it will drain your battery.

I have a 3,500 and run one thing at a time.

Gas furnace. ALWAYS leave generator outside. I cut power to furnace years ago and added a standard male/female plug that I can then plug generator into. I run cord from generator poutside through class block window vent or dryer vent from outside and stuff it with rags to seal it off.

I also run fridge or freezer if need be in hour shifts.

Having some water ahead to flush toilet is nice to have too.

I also make sure I have propane for the grill.

If you're real paranoid start freezing stuff. Then put it into coolers ot use so you don't have to open fridage incase power goes off. Canned food is always good but nothing worse than loosing good food in the fridge or freezer.

I just bought a 1500W inverter for the storm. However I ONLY intend to use it for keeping the chest freezer and fride going (alternating from one to the other). I did a little experimenting yesterday, and you need to understand that you will be VERY limited with this setup. It works just fine for my intended purpose, but it cannot handle large loads. FOr example it immediately shut itself off when I tried to use it to run my circular saw. It was able to run my freezer and coffee pot at the same time, but the display was indicating it was pulling 1200W.

I purchased a Cobra 1575 from Amazon and wired it with 4ga wiring (20" worth) directly to the battery with bolt down terminals. Throughout my entire 1hour test the jetta was just fine and the display on the cobra never indicated below 13.2 incoming volts (that was when boththe coffee pot and freezer were running). With just the freezer it never went below 14.1v incoming to the inverter.

You mentioned well pump.....most inverters I researched do not put out 240v. My well pump is 240v, so that was out of the question. I did not want to even attempt re-wiring the inverter for 240.

14 volts X 120 amps (the OP's alternator rating) comes out to 1680 watt capacity. Based on this I would think he can get by with the 1500 watt inverter, but can only run one or two appliances at a time.

To redo the math.. a 5000W inverter at 14V, assuming 90% effeciency, will draw 5000/14*0.9 or nearly 400 amps from the alternator... not gonna happen.

The math on a 1500 inverter just about works for the 120A alternator, although the alternator will probably not be able to deliver the full 120A at idle.

My guess... even with the math that says this just squeaks by I think some fridges and freezers may or may not work... the compressor will be a pretty big load when it tries to start.

Per a previous post... you will also need jumper-cable sized wiring between the alternator and the inverter... 120 amps is welding current and beyond.

I run a small fridge off an inverter in my boat. It draws about 2A ac running, about 5 time that on initial start. Inverter is cheapo 1000w and runs it just fine. A normal domestic fridge probably pulls 3-4A ac, chest freezer about 2A. Jetta should be able to handle those long term. Consider rigging something to elevate idle to maybe 1500rpm as that makes life much easier on the alternator.

Running well pump will take a BIG inverter. Those motors take lots of amps to start.

If you do get an inverter big enough to start well pump, consider getting some more batteries and parallel them. That will soften the shock on the car system.

Another option is to buy a west marine 12v dc boat fresh water pump. If your well is shallow, tee into suction and this positive displacement pump can draw a pretty good head. Plumb output to your domestic plumbing through a garden hose spigot. Pump does not move much water, but it will do the job. They draw maybe 4a dc.

Most solar power system use deep cycle batteries. These are set in parallel to maintane a constant 13 volt supply to the invertor. Most of the systems are figured is amp hours of operation. With most solar power systems it is the amount of time the invertor will be used. Most good invertors are full sine wave invertors these are the more effcient. You have to figure your wattage as far as what you will have plugged into the invertors circuit. Most energy effcient appliances use little amperage on start up. The older freezers and refrigerators pump motors pull high amps on start up. Most home energy savers which are nothing but banked capcitors maintane amperage at the DP or your breaker box to prevent amperage spikes from appliance motors. This reduces the pull from the meter and in theory you use less electricity. Older single phase squirrel cage motors pull a lot of amps at start up. The newer energy effcient appliances have better designed motors with more effcient windings, but are touchy during brown outs and amp surges.

Ski in NC said:

Another option is to buy a west marine 12v dc boat fresh water pump. If your well is shallow, tee into suction and this positive displacement pump can draw a pretty good head. Plumb output to your domestic plumbing through a garden hose spigot. Pump does not move much water, but it will do the job. They draw maybe 4a dc.

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This will not work if the well is more than ~30 ft deep - a shallow well indeed.
That is why well pumps are submerged and pump with pressure, not suction.

Even a 1500 watt inverter will draw over 100 amps at full output and the alternator only puts out maybe 30 amps at idle.
I have a 12vdc motor-generator that I used after an earthquake out here.
It was great for the TV and a lamp or two. A full-size home refer was not an option.

Lots of east coast wells could be pumped like this. For example mine is 90', but the water table is only about five feet down. But yep, a suction pump cannot draw any higher than the equivalent atmospheric pressure.

Good to know.

Another thing to keep in mind is the duty cycle of the alternator. Very few, if any automotive alternators are rated for continuous maximum output. I am not sure about Bosch, but Delco alternators are only able to produce maximum output for 5 minutes before having major heat problems.

Paul

i think it's funny how a poster will ask a question but never to return to the thread to remark on the outcome.

Sent from my Asus laptop using my Fingers 10

deejaaa said:

i think it's funny how a poster will ask a question but never to return to the thread to remark on the outcome.

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Given his situation I would venture a guess that having internet access is not a top priority if his house/belongings have been affected by the hurricane.

Sent from my Galaxy Nexus using Tapatalk 2

I can run everything except my central a/c with my generator. 6K watt. I've become an expert providing my own power.

He may not be back if he hooked up a 5000 watt invertor to his Jetta..

deejaaa said:

i think it's funny how a poster will ask a question but never to return to the thread to remark on the outcome.

Sent from my Asus laptop using my Fingers 10

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It is a sticky situation out there. I would have gone with biggest inverter I could get, because I have a 1500 watt and it doesn't do much. A TV, drill, not a hair dryer on full setting. Thats why when I heard well pump I thought oh no.

Also why I have everything gas I can.

My hot water heater(one of those tankless jobs with endless hot water and I have public water here at home but not in the mountains), stove, and furnace (which I have wired to run off generator).

Not all folks have gas available though.

Gas and public water rarely have interruption. And when they do it's usually very localized and short lived.

I dealt with the situation this past summer when we lost power for 8 days in central ohio. This was my setup:

The inverter is for an RV/Boat with an AC input and output. Had a 1000watt POS generator hooked up to the input. When the generator was running it would charge the battery, and pass through power to everything on the AC out. THen at night I would turn the generator off and the inverter would kick back in to provide power from the battery. Battery didn't last long under load, but I could at least turn some lights at night and in the morning.
My small chest freezer only drew ~110 watts running.

david_594 said:

I dealt with the situation this past summer when we lost power for 8 days in central ohio. This was my setup:

The inverter is for an RV/Boat with an AC input and output. Had a 1000watt POS generator hooked up to the input. When the generator was running it would charge the battery, and pass through power to everything on the AC out. THen at night I would turn the generator off and the inverter would kick back in to provide power from the battery. Battery didn't last long under load, but I could at least turn some lights at night and in the morning.
My small chest freezer only drew ~110 watts running.

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I was involved with that, the AEP thing. Well the ice storm one a couple years ago. We were without power for quite awhile.

750 W inverter kept the sub pump going last year with Irene , saved the basement.