Run Whole House on Wimpy Generator?

[redpoint5]

Interesting point about using waste heat. An ICE probably wastes more heat in a 15 minute drive than all the hot water I'll use in a day. If only it could be stored for when its needed.

The 2 accessible vehicles these days are an EV and PHEV, so I'm not wasting heat energy so much anymore.

That brings me to the likely conclusion of this thread; using my PHEV as a generator in the event of an extended power outage. I bought a 3000 watt inverter, and can wire it into the 12v output of the PHEV. The DC/DC converter keeps the 12v battery topped off, and the engine will turn on any time the high voltage battery runs low.

[j-c-c]

I thought the current crop of car EV batteries run in the 240-600V range?
What common available invertor operates off of those ranges?

[vteco]

I have a 6 hp listeroid diesel one lung generator which will put out say 3kw usable with a 5kw gen head. I have a bank of 6 UL approved manual transfer switches which isolate the generator. That isn't enough to run the whole house(no water heater) but will provide water, refrigeration, and most lighting circuits, including kitchen if used conservatively. This system is used in power outtages in our rural area.

I have also lived on a homebuilt houseboat, off and on for 10 years which I traveled in for 1700 miles. In that I used a small gasoline powered generator, a 1200 watt inverter/charger (Heart Interface) and 3 deep cycle 100 AH marine batteries. Shore power occasionally recharged the batts whenever possible, since the generator was objectionable to run in close quarters. The inverter had an automatic transfer switch, automatic battery cycler as well as the normal stepped charge rate charger. It was very smart for the time.

Can what you are proposing work? Not for a whole house if the total house draw exceeds the inverter's capacity. Or if the demand period exceeds the batteries capacity. Seems like those figures are the first thing you want to establish before buying anything.

In fact, if you don't own one already, your first purchase should be a Kill-A-Volt.

Feel free to ask any questions about this subject, as I've been through years of this stuff.

[Logic]

Originally Posted by redpoint5

Interesting point about using waste heat. An ICE probably wastes more heat in a 15 minute drive than all the hot water I'll use in a day. If only it could be stored for when its needed.

The 2 accessible vehicles these days are an EV and PHEV, so I'm not wasting heat energy so much anymore.

That brings me to the likely conclusion of this thread; using my PHEV as a generator in the event of an extended power outage. I bought a 3000 watt inverter, and can wire it into the 12v output of the PHEV. The DC/DC converter keeps the 12v battery topped off, and the engine will turn on any time the high voltage battery runs low.

Some electric cars are already V2H (Vehicle to Home)
or V2G. (vehicle to Grid)
Your's not?

It seems a waste to take HV down to LV then back up to HV again then AC it.
Especially when the HV battery already has a variable frequency inverter on it to control motor speed.

Maybe some sleuthing might come up with a way/circuitry to get HV AC from that inverter.
Perhaps even at the right voltage so you avoid needing a transformer.

As for heat from a PHEV;
a heat exchanger that just stands behind the exhaust would be easiest.
But not worth blumbing into the house hot water for once in a blue moon usage IMHO.
Time better spent playing UnDecember!?

[redpoint5]

Originally Posted by vteco

Can what you are proposing work? Not for a whole house if the total house draw exceeds the inverter's capacity. Or if the demand period exceeds the batteries capacity. Seems like those figures are the first thing you want to establish before buying anything.

The DC-DC converter in the PHEV outputs something like 2,000 watts, which kinda doesn't matter much since the 12v battery buffers the output. During the day my house averages 500w, so the DC-DC converter can easily keep up with daily demand.

The inverter can't power the whole house because its 120v. It can power half my circuits though, which includes the main living areas, HVAC blower, washer/dryer (dryer is natural gas), fridge, deep freezer...

Runtime is infinite because the gas engine kicks on whenever the high voltage battery runs low. I get about 12kWh from a full charge, so that would last about a day of normal use, or probably 2 if the power was out. There is also a trick on the van to force it to run the ICE by opening the hood. It will charge the battery while the ICE is running, and will replenish the ~12 kWh in about 2hrs.

I've got everything needed to run this setup, just haven't tested it yet.

[Piotrsko]

Going to be extremely difficult to get and maintain a stable 60hz A/C voltage out of even a series DC pwm traction controller used in the main drive, less possible in a bldc across one set of outputs. If the device accepts between 50 & 70hz, then maybe and only if you can get the controller to not shut down from output errors on the other 2 phases.

Go look at high power standby server power systems if you don't believe me.

[redpoint5]

Originally Posted by Piotrsko

Going to be extremely difficult to get and maintain a stable 60hz A/C voltage out of even a series DC pwm traction controller used in the main drive, less possible in a bldc across one set of outputs. If the device accepts between 50 & 70hz, then maybe and only if you can get the controller to not shut down from output errors on the other 2 phases.

Go look at high power standby server power systems if you don't believe me.

I have no idea what you're talking about. Why would I want a 60hz AC voltage out of my DC controller?

[vteco]

Well redpoint5, the proof of the pudding will be in the actual running.

In theory the ratings of these components can provide 500 watts of house power, and your battery/ inverter method can absorb some degree of surge current and also provide inverter rated wattage above 500, depending on the batteries' capacity and usable discharge rate, and on sufficient wire sizes to handle the battery current. (Also you definitely need a transfer switch to ensure power line safety when testing a real house circuit.)

If demand, or the demand period, or any other cause exceeds those ratings or capacities, or the wiring is insufficient, one or more of those components will fail.

The two you don't want to fail most are the battery wiring, and the transfer isolation. The others may simply brown out or not work.

Be aware that some appliances don't tolerate low voltages well or altered AC frequency or waveform, which can happen if a source component like an inverter is overloaded.

I would like to see you try it, I'm not a nay sayer, but I would suggest gradually adding circuits while testing to ramp up slowly to your target power. And trying only resistive loads to start. Those are getting harder to find at least in the house circuit with the demise of the incandescent bulb. But I'm sure you could rig up a non house test circuit.

An electric coffee maker (if not too smart an appliance) can provide a test of an excess load, if you're already running a test circuit with incandescents at 500 watts.

If that works out, maybe run a small shop vac to test motor start and inductive load. Relatively inexpensive, and unlikely to burn out. Not like a refigerator.

[redpoint5]

Originally Posted by Piotrsko

Going to be extremely difficult to get and maintain a stable 60hz A/C voltage out of even a series DC pwm traction controller used in the main drive, less possible in a bldc across one set of outputs. If the device accepts between 50 & 70hz, then maybe and only if you can get the controller to not shut down from output errors on the other 2 phases.

Go look at high power standby server power systems if you don't believe me.

I've got a 4-day weekend coming up, so maybe I can test then. The math all works though.

I recommend most people get an interlock, but I'm not going to. There's not a ready way to affix one to my panel. I'll also be testing in a less incremental way, just because going all the way is in my nature. I prefer to start at the most likely point of failure and work back to success, instead of starting with success and working towards failure.

Looking at the past 48hrs, household electricity consumption peaked at 1800 watts briefly, minus 240v circuits like the oven and EVSE. Average consumption over the past week has been 540 watts.

I plan to test the half of circuits most important to me in a power outage. I do not yet own an oscilloscope, so I can't keep an eye on waveform, but I can keep tabs on voltages and current.

[vteco]

Originally Posted by redpoint5

I prefer to start at the most likely point of failure and work back to success, instead of starting with success and working towards failure.....

I do not yet own an oscilloscope, so I can't keep an eye on waveform, but I can keep tabs on voltages and current.

Well there's always the fourth alternative, starting with success and working towards success.

Not waveform, but definitely frequency readout is available through a Kill-A-Volt, and is important to things like refrigerators. Just sayin.