A layman's guide to using a prius as a generator

Are you using a 3kwatt inverter powered from the 12volt starter battery?

That is not accessing the wattage available from the main-battery, nor from the actual ICE.

 

The inverter is not really powered off of the 12v battery. It runs off the DC-DC converter from the HV battery. There is a 100 amp fuse in that line. 3KW at 12v is about 250 amps, so you will need to exercise some caution to avoid blowing the fuse.

 

Why a 3kw inverter? Isnt that a bit much for the 12v system?

 

Exactly.

The Prius generates a lot of electricity. But by tapping at the 12v battery you are only getting a tiny fraction of the vehicle output. And you are limited by that 100 amp fuse.

 

I am sure of that, but as others pointed out the 12V side will take more, efficency loss etc... remember the inverter actually operates over 14V not really 12 ...

Also in-rush currents for many things like fridge or other motors like blowers are huge... 3kw can blow your inverter/fuse ... that could be very expensive if the 100amp fuse is not fast enough!!!

You "MUST" fuse the 12V side slightly under what the inverter (prius' not yours) could do ... read on this in details in some other threads...

Also you can possibly melt/damage the wire from the inverter to the 12V battery the normal automotive fuse is SLOW.

 

But that's 100 amps at 120 volts - to supply that from an inverter you'd need a thousand amps on the 12 volt side.

As others have said, here and elsewhere, you need a fuse in the 12 volt feed to your inverter. I'd say no more than 80 amps.

 

I built one and just like you suggest 80 amp fast fuse on the hot wire of the 12V btw battery and the inverter. I also would be little concern about the wire and connections seem to be little on the low side.

Do I see that OP used gauge 4 wire ?? that seem to be under spec for 100-80A will have lots of loss aka heat on them. Better test it properly.

Also if this is a "permanent" install I would be worried about inverter and cable moving by during normal operation. I have my inverter stored and only small lead with connectors (andersen ?). I provided installation pictures page 4 and 6 ? in this thread which as a tons of info for OP ....

Using car as generator for house power | PriusChat

 

I read an article on this (can't recall the link) which stated that 1000w inverter is the max you should use for this.

 

see link above bwilson, I think, and others run the calculation better than I can do. Basically 100A fuse on the inverter and something inside the inverter will limit around 1460W before any losses. At this current even awg 2 gauge cable will have losses ... can' not remember what gauge is the wire from the front to back will have loss right there as well.

So consensus was that nothing over 1000W is practical. 1000W is on the AC side so for that you are maxing out the input pretty much. And last resort you want your inverter limiting the power flow rather than the prius's !!! (actually I put an 80A fuse to be sure).

Also 1000W sustained maybe also risky wires/connection should be monitored for heat.

Anyone wants higher power should consider tapping the HV battery there are some detailed article explaining that process.

 

4 gauge wire should be OK for a short run in free air. It's rated at 135 amps under those conditions:
Wire-Gauge Ampacity - Transwiki

 

well that is what I thought so sustained load even just about 1000W inside the shown enclosed setup is a risk, in my opinion ... again it needs to be tested/monitoried wire temp especially around connections ... I wouldn't do 1kW drain for any extended period of time with this setup (or even with my own) ...
remember 1kw output will take at least 10% higher on the DC side running close to 100Amps sustained that is on the edge !!! AND real problem is when wire heats up it increases its resistance so make the things worse !!! and can easily have a run-away situation ..

As people smarter than me said anything over a 1kw is not really a good idea (possible for short, really short period of time) ...

 

Because you don't seem to understand the difference between amps on the 12VDC side and amps on the 120VAC side, I'm getting premonitions a blown Prius in your future.

 

The amp rating for 12vdc is very different from 240vac. You need to check the solar wire amp ratings to do it correctly. Also, anything that will run more than 2 hours needs to be derated....check the code. Working with batteries can be very dicey. They like to discharge explosively if you are not careful. Always use fuses and make sure they are DC rated.

 

i hope the o/p is uninjured.

 

You got the wrong inverter for your setup. If it was that easy slapping on a 3KW inverter then everyone will do it. The Prius's 12V system is only safely capable of handling 1000W max. Personally I wouldn't hook anything up more than 500watts to the 12V system. The Prius has no alternator. It get's 12V power from a converter that takes the power from the HV battery and step it down to 14.4V to run the electrical system and to charge the battery. It's not as cheap to replace like an alternator. The factory converter is extremely expensive to repair and replace.
The proper way to setup a Prius generator is to use industrial UPS that matches the Prius's HV battery voltage. This will bypass the stepdown converter. It's taking power directly from the HV battery. If it goes low, the engine kicks in to charge the HV battery. This will give you the 3000 watts of power you need.

 

Yes it is. The 12v system should only be tapped for up to 1kw power [fuse related]. For more power, I recommend the hybrid battery attach version [plugoutpower.com, full disclosure.. my company]

 

Good information except that a UPS hack isnt the only way to get more power. Look for plugoutpower.com for hybrid battery attachements.