Using a Prius as a generator

Re: Using a Prius as a generator

techntrek wrote: »

I wonder how they do their math, 30 amps @ 240 volts = 7200 watts.

Think about 208/120 three phase perhaps?

With 30A on each of the three phase wires that would be 90 x 120 for 10800.
Or 240 delta for 12,240. Getting closer....

Re: Using a Prius as a generator

I tried this over the weekend. I have a 2006 Prius that's getting up there in mileage (140,000.) I got a 2kW AIMS inverter from Ebay:

http://www.ebay.com/itm/AIMS-Prius-2kW-Pure-Sine-Wave-Inverter-for-Backup-Power-Generator-/200841111789

Went pretty smoothly overall with the exception of that damn orange safety plug. It is a bear to get back in right, and it took me 2 hours of fussing, poking and prodding to get it back in correctly, wondering all the time if I'd have to get a tow truck to tow the thing to the dealer if I couldn't get it back in. You actually have to reach into the battery and get your finger on the other side of the signal connector as you are seating it, which to me sorta misses the point of a safety plug.

The inverter came with a simple wiring harness. I used a 12 gauge extension cord with a straight blade 240V 20A connector on the end. That's unusual enough that the odds of someone seeing it and thinking "you know I can just plug my X in there!" is pretty low. I added a 30 amp fuse just in case in the cable to the inverter.

Finally I got it all connected (and got the safety plug back in) turned on the car and turned on the inverter. It ran a 1500 watt heat gun with no problem. On a scope the waveform looks very clean, although it does something odd on startup - ramps smoothly from 0 volts to 120 volts over the course of about five seconds. I've never seen an inverter do that before, and I'm not sure what it would do to your average appliance.

So I am now better prepared for a longish blackout. (Of course, in San Diego these almost never happen.) I am also prepared to power entire tent cities at homebrewing campouts, tailgate parties and Burning Man.

Some pictures below:

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Re: Using a Prius as a generator

There is an older Prius in our family (Son-in-law). I've got his interest in potentially integrating it into my solar system that is installed in a remote location. My electric co-op gave me a really sweet deal on an on-grid installation, and I currently have 14 SolarWorld 280 monos feeding a SMA Sunny Boy 4000 TL-US. Currently I am installing some "hybrid" equipment to keep my golf cart batteries (and spare set) charged for use during a long outage. I also have a gas-guzzling, extremely loud, but powerful electric start, split phase, 6500 watt generator to run my well pump so that we will always have water (and maybe some selective air conditioning use). This will take some real rationing of gasoline, but I'm prepared to do that.

Down South here in Texas Gulf Coast, we can have rather long power outages due to hurricanes of up to several weeks - in my case it could be months at the end of the transmission system deep in the country. So to use the Prius (just drive it up to my Solar System and hook it up! - it is located in an adjacent storage shed), I'd need to get around 4000 watts of 240 volt split phase electricity on demand - that would just be phenomenal. It would be great to integrate the 8 - 155 AH golf cart batteries (2-48 volt strings) also as they can consistently be charged by the existing solar system - and keep the gasoline usage to absolute minimum. What would be ideal is a highly flexible inverter that could take the traction battery output (sort of like it was from the traditional PV panels) on demand, and use the recharged 48 volt Cart system batteries for the majority of power supply. I'd think that this type of inverter could also recharge the 48 V batteries (from the Prius) if needed during extended cloudy weather -just to keep them in good condition.

Bottom line is the ability to produce the 240 volt split phase for short periods of time - almost indefinitely, which seems possible IF both the Prius (rationed gas) the 48 volt battery system (solar) can both feed a 240 V split phase inverter. Of course, the constraint on my grid-tied inverter is that it will not make split phase power unless it is on the grid. This SMA inverter does make 120 v AC - up to 1500 watts off-grid however which will be used to charge the 48 v battery bank during sunny times.

I have recently joined the post and a newbie to renewable power, and realize this might be totally impractical, but whats the fun in being practical!

Mark

Re: Using a Prius as a generator

techntrek wrote: »

Welcome. Unfortunately you won't find an inverter and/or charger that will accept 48 and 192 volts DC. Your best bet will be to get one of the UPSs I mentioned earlier (and transformer to get the 120/240 split phase) and use that to power your well pump, and a 120 or 240 volt charger for your batteries, also driven by the UPS/transformer.

That certainly seems to be the case. Is there a specific APC model number for this split phase transformer? It seems these UPS prices are all over the map on ebay now!

Out of curiosity, how do the APC UPS get the back up batteries to a high enough voltage to drive its inverter? Has anyone added "battery backup" of a substantial amount directly to the UPS - and basically rid the system of a second battery backup (e.g. 12,36,48 volt traditional lead/acid)? To make this functional it seems one would need to find a (PV) charge controller that could charge this (powerful) UPS battery system directly?

Not being an electrical engineer/designer, probably missing some functionality here, but it sure seems you are on the right track for Prius owners that are seriously interested in substantial emergency power. If our family all showed up at our remote home during a hurricane (which did happen during Ike), with full tanks for gas in every car, plus my planned storage, we could go for months with the Prius concept and be fairly comfortable.

Re: Using a Prius as a generator

MarkC wrote: »

Any thoughts on using the Prius with a traditional off-grid 48 volt system (Seems as if most ~ 4000 watt off grid systems will use 48 DC volt systems)? It does appear possible to use a charge controller (one of the higher voltage types) to charge a traditional 48 volt system directly from the traction battery - when the solar charge controller is "in the dark". These have all the "bells and whistles" to properly charge the batteries. There are a few 48 volt in /240 split phase out off-grid inverters out there, but quite expensive and generally have a second AC input (generator support), and can charge the batteries themselves. However, they are quite efficient and fit for service.

The one problem there is that charge controllers require one side of the "array" (the prius in this case) to be grounded, and the Prius has extensive ground fault protection. You _might_ get it to work by relying on the resistance between the car and the actual earth ground, but it would be worrisome to me.

As an alternative consider a DC/DC converter set to output charge voltage (say 54 volts.) For example the RSP-2000-48 will work from a 130-360 volt DC input and give you 54 volts out at about 40 amps. You will have to be careful about current draw since the RSP-2000 cannot run in current limit for very long.

Re: Using a Prius as a generator

I was trying to decide (using the Prius) if it makes more sense to invest in a more or less standard off-grid inverter that would be powered by two sets (48 V) of golf cart batteries combined in parallel. One set maintained by a Midnite Kid from 6 solar panels and the other maintained by a Classic 250 from the Prius directly. I need the second set as spare anyway as the current set is fairly old.

The off-grid inverter would be a 4000 watt split phase type and I would use all it's capacity to run a 1.5 ton AC and a 3/4 hp well pump (both split phase - plus some other small users). I realize, likely will have to start each of these separately, but this would be utilized only on extended outages - more or less in a "survive with water and some level of comfort in summer time Texas".

Other alternates are a much more efficient split phase generator (sure wish Honda would make the 2000 watt "companion" series with a combined split phase output) - or - using the UPS route you have taken with the Prius. At this time, I'm just working thru the advantages/disadvantages and not really ready to do the actual design and "put my money where .....". Maybe other alternates I've not thought of?

Re: Using a Prius as a generator

I have a rather high efficiency "hotel" style AC unit that draws about 5-6 FLA. Don't know startup. The well pump would be operated manually to refill containers and tubs for use as needed - not pressure up the house. The AC would be on from early evening to morning - for some comfort in sleeping. Both are 240 v split phase. Not sure of the well pump FLA or startup surge requirements. Again, this scenario is well into a long term outage while the local co-op is repairing lines after a hurricane - probably at the most 2-3 weeks. Not thinking at all of full house backup.

Can't spend lots of money on this, but I need the 8 - 155 AH 12 v batteries anyway for my "off-road" golf cart - one operating and one spare set. Just trying to figure how to best use them - with the Sunny Boy SPS as a given - I've already determined that will work well to charge one set of batteries - as long as we have some sunny weather after the hurricane, which is normal.