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Discussion Starter #1
I am wondering about "hacking" on the ability to work as a whole house generator.

Idea: connect solar inverter (I have 3x4KW) DC side to 300V bus.
This is the difficult bit depending on GM's design.

Keys in or near the "ignition" -- i.e. Volt switched on. But in "neutral" -- i.e. not forward or reverse. Hey I've just realized that every day car terminology does not even apply to the Volt!

Wheel clamp on wheel to stop car being stolen (since keys are present).

Breaker to grid for house switched off to avoid back feeding grid in case power is restored (and inverter configured not for grid tie - anti-islanding disabled or using non-grid tie inverter). Or connected via transfer switch.

As long as Volt is not so smart to wonder why the SOC is going down but it is traveling nowhere (0 miles per KWh), this sounds like it would work, and all that is needed is a 300v tap. Better still if the Volt can be "on" but immobilized without the wheel clamp and without leaving the keys in.

Does this sound practical to you or have I missed something?
 

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I was going to tell this guy to search the forum for backup generator but discovered that the search function does not work. Anyone else having a problem with this? Anyway, many of us are thinking about hacking some or many of the systems and using them for our own applications. Home backup generators, Super drag racers, Four legged robots, etc. You name it. I thought for a moment you were thinking of putting the Volt up on jack stands to fool the computer! lol. <cough> I was just joking by the way. ;)
 

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You're going to need to be a software hacker too. This is not any old ordinary generator set. It is not designed from what I can gather to operate at a constant 1800 or 3600 RPM like ordinary sets do. It is going to be variable rpm and voltage I believe depending on the car's needs. This will reek havok with you inverter. So I believe that in addition to taping into the power and interfacing with your house, you will also need to do some special programing to the Volt's computer systems so that it can just run a constant rpm and provide stable voltage.

Seriously, is the power service to your house that bad that you need to go to all this? Stationary backup generators really don't cost that much and can run on a variety of fuels. Seems simpler that messing with a very complex car and voiding your warranty.
 

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There have been discussions about this with the existing hybrids as well.

I don't think the auto-manufacturers are ever going condone this because it will put excess wear on the car that won't be accounted for on the vehicle's odometer and therefor affects the warranty.

Besides, one has to wonder if it is cheaper and/or cleaner to run your house off of the car by burning gasoline or to buy the electricity from the electric company?

I suppose I could see the value if it were to only be used in an emergency power situation. it would definately be less polluting than a typical stand-alone gas generator.
 

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I would think it would be much less dangerous to both you and your Volt to just buy a generator for your house.....

And Texas, you are right about the Search not working. I tried to use it to find something last week, and had no luck at all.
 

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Ford is currently working with Southern California Edison to provide this capability in prototype Ford Escapes Hybrid Plug-Ins. Sadly they don't believe that the car will find its way to the masses for years. Living in Hurricane Central I am very interested in this type of option to avoid the traditional gas generator especially at night whe I want to sleep and would like to avoid CO emissions creaping into my house. Hopefully, GM will introduce this type of operation once they get comfortable with the Volt performing its current mission (to work).
 

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Seriously, is the power service to your house that bad that you need to go to all this? Stationary backup generators really don't cost that much and can run on a variety of fuels. Seems simpler that messing with a very complex car and voiding your warranty.
There are probably 30 million people near the Gulf and South Atlantic coasts that have seriously that bad power issues in the last few years. Many, many people now have permanently installed or portable generators and the rest wish they did. Permanently installed whole house generators do cost a lot. A 20KW one that does self-start maintainance will run $10K and up installed.


Adric22

You must not drive in big city traffic. Cars routinely sit idling through 1/2 or more of traffic per work day. I doubt the Volt will have duty cycles or warantees for the batteries and genset based on odometer miles. I expect them to be based KWh output for the battery and hours of operation for the genset. It probably will be significantly cheaper to get power from the grid but most (if not all) people want v2house for emergencies or other away from grid events.
 

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0 to 60 numbers

You know, with a ~135kW motor, the 0 to 60 numbers are going to be a lot better than we've been lead to believe. As the Motor Trend article puts it, "...as they promise, the 8.5-seconds-to-60 Volt turns out to be a good-looking, no-compromises, fun-to-drive family sedan." I remember doing a Dodge Neon EV conversion with a 45kW motor, and it did 0 to 60 in about 10 seconds.

I think that it's purposeful obfuscation. The Volt is not going to be a family sedan. It is not going to be a Tesla roadster either, but I wouldn't be surprised at sub 6 second times.
 

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Volt as a backup generator

It would not take much to offer backup power AC as an option. I bet that will become a common feature in the future. There are all kinds of reasons I'd like to have a 115 volt outlet on my Volt. wYou don't want to mess with the onboard generator or existing power electronics that control the motor though, though. It's easier to do it with a separate inverter.

Taps off the DC bus could feed DC to a 120/240 volt, 60 Hz AC inverter. If the intent is backup power when the grid is down, this would probably take an inverter that is not quite available yet, as most off-grid inverters are designed for between 12-48 volts DC input and the Volt will have 300+ volts DC on the DC bus. This would be relatively easy for the existing inverter manufacturers to make, though, as they already make grid-connected inverters for the PV market that take up to 600 V DC input. Actually, the higher the input DC voltage, the lower the inverter cost, as the power transistors that do the switching to convert DC to AC have to handle fewer amps.

I suspect that, regardless of what lowers the battery charge, once they hit the minimum point, the onboard generator will kick on and keep them happy.

Here's a link to a typical inverter manufacturer that makes both grid-tie and off-grid inverters:
http://www.xantrex.com/index.asp
 

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Taps off the DC bus could feed DC to a 120/240 volt, 60 Hz AC inverter. If the intent is backup power when the grid is down, this would probably take an inverter that is not quite available yet, as most off-grid inverters are designed for between 12-48 volts DC input and the Volt will have 300+ volts DC on the DC bus.
It may even be simpler than you think. I'ld have to check what the commercial UPSes and Emergency Lighting Inverter systems use, but I would be surprised if they are not optimized for inverting battery DC to 120/240.

Shoot, even my stock Vibe has a 120V outlet.
 

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more inverter thoughts

APC and Liebert make some high VDC input inverters for their larger UPS systems, but they are $$$$$.

For residential-grade low kW inverters, there isn't anything right now that can handle 300 VDC input.

It would be very easy and inexpensive, though, for GM to fold in some additional circuitry to make the onboard battery charger a reversible charger/inverter. A lot of the current generation of off-grid inverters are designed to work in reverse as battery chargers, too.

If the grid-to-vehicle concept takes off, this will be a requirement, as the only way the utilities can take advantage of pulling some power from the vehicle batteries during peak demand will be if the charger can reverse itself and become a utility-grade grid-connected inverter, too.
 

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Regarding use of Volt vehicle battery to backfeed the AC line -

A line-commutated inverter configuraton for the charger is not a problem. The charger semiconductor bridge can be configured and controlled such that the power flow can be reversed, to flow from the battery and back to the AC line. Problem is that a 120 V, 20A branch circuit can only be loaded to 80%. This allows a maximum of 120*20*08 = 1920 VA back to the home. Not very much to offer. A bit of load shaved to cover power drawn from your home's air conditioner. I don't think it is really worth having a line backfeed capability.
 

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It doesn't look like much, but it's almost as much power as a typical residental 2 kW PV system that California's Governator thinks will save the state's grid. At $15k for a 2 kW PV system, a back-feeding plug-in hybrid looks like a pretty cost-effective peaking power source alternative.

Here in Redding, CA (pop. 85,000), peak summer demand hits about 150 MW. If the local utility can even knock 5% off the peak with distributed sources of power, it would be worth a lot to them. 7.5 MW = about 4,400 plug-in's, each feeding 1.7 kW to the grid.

I wouldn't be surprised if we don't see some hefty rebate incentives coming from the utilities to go with EV's with smart charger/inverters, if nothing else than to help with peak power issues.
 

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I was thinking more along the lines of 120/240 out but even a single 20A 120V would be better than nothing. Absolutely, V2G could be a huge benefit and I'ld hate to miss out on that opportunity down the road as well as V2House. It would take very little to design this into the Volt (at least the hardware capability), plus it might cost a lot to add after market. If it's V2House capable out of the box, then V2G should be a snap if it becomes available later on.
 

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The northern San Juaquin valley gets pretty toasty in the summer - You are right.

The buyers of the Volts will have to contribute to the Cal-Iso's (California Independant System Operator) and PG&E's (Pacific Gas and Electric) load shaving solution by staying plugged-in. I don't really think that is going to over well with the folk that want to drive to Lassen Park or Lake Shasta to get out of the heat.
 

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Discussion Starter #16
I haven't seen any reason why it cannot be done

I started this thread.
So far I haven't seen any reason in the replies why this cannot be done.

The inverters that I currently have handle anywhere between 180V DC and 500V (or maybe 550V) DC. They are each rated for 4KW, and I have 3 of them. I've used them down to 200v and up to about 270v with my solar system(s).

If I tap off the Volt's DC bus, then I can run that cable separately from the Volt's charging cable, so I am not limited to 20A at 115V. I am limited by max current for cable x Volt's DC bus voltage.

Why would I do this. Because a 4KW standby generator costs a lot in terms of $ and embedded energy, and has additional servicing and noise and fuel storage issues, and I want an emergency backup (enough to start and power 3KW heat pump).

The two biggest problems that I foresee is safely tapping the Volt's DC bus, and having a means to reconfigure the inverters, since to run without the grid tie facility (anti-islanding) requires software reconfiguration, but being a software engineer that is not beyond me. Automatic transfer would be more complex, but that's not a problem for me.
 

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Electrical Safety

Do not connect any kind of generator and inverter to power your house mains without installing an approved transfer switch! :eek: Simply using your main breaker to isolate your house can result in an "oops" situation, where you forget to switch your breaker but you start your generator or inverter and end up powering the neighborhood. This can result in severe danger for anyone working on the powerlines.

The transfer switch is an "A or B" kind of switch - you can't set it to an unsafe position.

Regards,

Altazi
 
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