[PsYcK487]

To start with.

Lets say you are interested in hooking up a 1000W 12V DC to 120V AC inverter to your chevy volt. Of course this is possible and has been done.

The question, is it possible to parallel the 12V systems of two same year Volts into one larger say 2000W inverter? Would a capacitor placed in the correct location assist in doing this?

I know this would certainly void the warranty of the vehicles and a bunch of other things. I'm just curious if this is theoretically possible.

Anyone link to take a swing at this one?

 

[emg77]

When paralleling AC systems, you have to get them in phase or bad things (big booms) happen. You'd need parallel monitoring equipment and other expensive equipment to do it. The only time it's done much is when paralleling the outputs of multiple standby generators for places like hospitals or data centers. Possible, yes, but highly dangerous and cost prohibitive.

 

[jcanoe]

If you were just to wire (2) 12V batteries in parallel then maybe it would be possible but with (2) Volts each with their own 12V DC system wired together I think not. There is nothing in the Owner's Manual that cautions against jump starting one Volt with a second Volt which is basically the example you posed but jump starting only connects the 12V systems of both vehicles for a short time. Over time connecting the 12V systems of two Volts might cause the Accessory Power Module (APM) present in each Volt's 12V circuit to malfunction if this circuit was allowed to operate continuously.

 

[canehdian]

Better off making two 1000W circuits and load balance your items on each.

Doesn't help if you have one 2000W draw, however.

 

[supchrgamx]

put a diode in on each 12volt source and have at er

the higher voltage on one of the two sources will pull higher current than the other till they match voltage

 

[Don M]

Lets say you are interested in hooking up a 1000W 12V DC to 120V AC inverter to your chevy volt. Of course this is possible and has been done.

The question, is it possible to parallel the 12V systems of two same year Volts into one larger say 2000W inverter?

Why not just hook the 2Kw inverter up to a single car? I think the Volt DC to DC converter is rated for 2 Kw . . . . 165 amps @ 12 volts

http://store.evtv.me/proddetail.php?prod=VoltAPM

Don

 

[canehdian]

Why not just hook the 2Kw inverter up to a single car? I think the Volt DC to DC converter is rated for 2 Kw . . . . 165 amps @ 12 volts

http://store.evtv.me/proddetail.php?prod=VoltAPM

Don

Which is fine, but the car itself needs minimum ~200W from the 12V system while 'on', more depending on what the vehicle needs to run in addition to base load.
General "safe" level is max 1500W for an inverter load or you run the risk of overloading the APM, blowing fuses, other undesirable outcomes when you are typically far from civilization in order to get it fixed to be able to drive home. Playing it safe is the better route.
If you could find a way to energize just the APM, then 2kW is within spec. But there are too many safeguards in the vehicle around HV when system off, it wouldn't be an easy task.

 

[edk-austin]

As mentioned, jumping one car from another parallels the 12V batteries. Voltages will then equalize between the two batteries, or will get pretty close depending on their condition. At that point, yes, you could draw 2000W pretty safely. There will be some I2R voltage drop in each cable, depending on the length to the load. If you can draw the load current from a mid point on the jumper cables, such that the resistance to load is equal from each +12V battery, then you approximately share the current from both Volts. In practical terms, one set of +/- jumper cables goes from inverter to car A, another identical +/- set goes from inverter to car B. Equalizing the cable resistance on each path, and having each +12V battery at similar SoC, is the key to balancing the draw from each car.

Normally, the "proper" way to do this would be with some big diodes, but I don't really see it as necessary for temporary use. The I2C voltage drops will self balance the system.

 

[srmarti]

I'd consider a stand alone back-up system before tying up two cars like this. Really, I just wouldn't tie up two cars for 2Kw worth of ac power.

 

[Loboc]

I'd consider a stand alone back-up system before tying up two cars like this. Really, I just wouldn't tie up two cars for 2Kw worth of ac power.

Yep, this is what I would do. Heck go 43kw and run the whole house on NG.

Still waiting for V2G.

 

[Dutch]

There is also the issue of the difference in potential that could develop between the two vehicles and whatever is pulling the power. I think you'd want to be very VERY careful about grounding.

Much simpler and safer (though not cheaper) to get an actual whole house generator built for the task

 

[srmarti]

Yep, this is what I would do. Heck go 43kw and run the whole house on NG.

Still waiting for V2G.

Well, one 2-4Kw portable generator is probably less expensive than the stuff needed to fit two Volts for 2Kw of AC power. I'm not waiting or sold on the V2G idea. I'm not so sure letting the utility put extra cycles on my vehicular battery is going to benefit me sufficiently. Utilities aren't completely sold on solar grid- tie and net metering. What makes V2G so appealing?

 

[summit]

Well, one 2-4Kw portable generator is probably less expensive than the stuff needed to fit two Volts for 2Kw of AC power. I'm not waiting or sold on the V2G idea. I'm not so sure letting the utility put extra cycles on my vehicular battery is going to benefit me sufficiently. Utilities aren't completely sold on solar grid- tie and net metering. What makes V2G so appealing?

One option is to have an external deep cycle 12v battery bank to power the 2kw inverter. Then you can "jumper' the Volt 12v to this external battery bank. Unless you need to pull a continuous 2kw, I think 1-Volt ought to be sufficient. Otherwise paralleling two Volt 12-v to this external bank ought to be fine. But definitely put in line some fuse/circuit breaker.

I have a 4kwh LiFePo 12-v bank, paralleled to the Volt/Bolt 12-v

V2G will be awesome, when considering the 60kwh Bolt pack.

 

[srmarti]

V2G will be awesome, when considering the 60kwh Bolt pack.

For what? Emergency backup power or letting the utility borrow back the electricity they sold you and put more cycles on your battery?

 

[PsYcK487]

Ok, a little more background info on the idea. If one owned 2 same year Chevy Volts. The price of LG Chem or any type of home energy storage system is very pricey. If it were possible two parallel the two volts, and use a larger 12 volt inverter, the equivalent energy storage system would be a competitive solution. 2kW output with almost 20kwh storage AND the volts themselves are gasoline generators. I know and understand all about ICE generators, but would like to exclude them from is thought experiment.

 

[PsYcK487]

This is an off-grid thought experiment and noisy gas generators are not sexy enough for it, as well.

 

[ratSnO]

Old thread but for the future searchers, here goes!
PsYck487 stated his idea clearly in the first post - two 12v batteries in parallel supplying one 2000w inverter

The answer is YES! Positive from both 12v batts to the positive on the inverter and likewise for the negative. Works like a champ.

This puts roughly half the burden on each Volt's 360vdc to 14vdc converter aka Auxiliary Power Module (APM), or if a gasoline motor car, the alternator.

Diodes are not needed to stop equalization between the two 12v batteries because the possible tenth or two of a volt difference is nothing to be concerned about.

Big gotcha hooking an house-power inverter to a Volt or Tesla or other EV is that you have to make sure the EV's 12v converter keeps running. If the EV 12v battery stops being charged from the big batter and the inverter draws it down until it quits, the EV won't even start. If the 12v lead acid battery is healthy, the voltage should recover in an hour or so which may be enough to start the car (called the Peukert Constant). If not healthy, then you'll need to pull up an ICE dinosaur and break out the jumper cables to bring your high tech car back from the dead.

A pertinent tip to keep the Gen 1 Volt running while just sitting is to hold the gear shift knob in with a piece of tape or a rubber band. Maybe Gen 2 also.

 

[srmarti]

Even if it could work, I wouldn't tie up two cars to generate 2 kw. It's a job for one not particularly large or expensive generator.