Using car as generator for house power

I did not notice it was 240VDC to 110VAC. That is meant to connect directy to the traction battery. I am clear now.

 

Do you have any comments on or review of the 12V version, or any somewhat similar AIMS inverters?

I'm also looking for any pictures from someone tapping into the Gen3 traction battery, beyond the single presumed G3 image on the above ebay listing. The Gen2 pictures look make it look reasonable enough, but mine is different and I haven't yet taken anything apart to explore it.

 

Lots of Amps with only 12v...

Alan.. Sent with Tapatalk 2

 

I don't actually want the 12V version, but want to hear about any performance issues or benefits that it might have in common with the high input voltage version.

 

I want to introduce fellow thread posters to a web site I had seen back right after Hurricane Sandy, and just re-read: IMHO this bears on our topic. The Web site's author Bob Bruninga appears to have attacked a lot of the issues we've been discussing back in 2007. I especially like Bob B's idea of rewiring solar panels to gain free daytime home appliance power during blackouts (last item on the page). Enjoy!

APRS Alternative Energy

 

I finally dug far enough into my battery & power assembly to see the same view as shown in the fifth (last) image on the ebay page, so that is a Gen3. What I found is not yet enough to scare me away, so this route (direct tap into the HV) is still an option. But more thinking is needed before I do anything.

The pink conduit in the ebay image is the added wiring to take power to the added inverter, and it looks like a good route for a pigtail to a power socket of some sort. I have a bit of larger 1/2" plastic conduit that appears identical to the conduit carrying the main HV lines towards the HSD (not shown), but it is too large and inflexible to fit as shown, at least without some modification to the sheet metal that it passes under. I'll have to look for some smaller stock.

This will still need some strain relief and chafing protection from that sheet metal. The black conduit next to the pink passes under at a point where the sheet metal is both cut back and bent 90 degrees, so it won't slice the conduit in a crash. But that feature may not be wide enough to protect an added second conduit.

 

Here's how Richard Factor tapped the traction battery on his 2005 Gen II for the PriUPS project.

 

For those interested here's a pic from a Camry hybrid.


Alan.. Sent with Tapatalk 2

 

This is one case where an Anderson connector works. At high currents with a 12V installation, the (I**2)*R losses are pretty ugly. But at 200V, the lower current makes the Anderson a good solution.

Now Richard's installation involves 'home' battery unit and inverter setup. So his Prius is in effect the recharger for the home batteries. Not a bad solution although we've not discussed 'in rush' risks. I would probably want a current limiting resistor on the initial connection that has a by-pass relay to allow a step-wise bypass of the current limiting resistor.

I'm still more interested in a permanent installation as this means we don't have to deal with connecting power electronics under the stress of a power outage.

Bob Wilson

 

Here is the second part.

I have installed the short end with the anderson to the battery here are some pics



Then put back the cover pieces and this is how it will be used when needed



That is the pigtail part





Here is when it is working...

I run test with 100W regular light bulb first...

then tried my fridge ... disappointment there it will not able to start the compressor all OK until the compressor motor kicks in then the inverter stops with error. The fridge is quite outdated (over 10 years old) so an up to date unit may perform better ... but I do not know.

I measured the constant load which is about 500-600W according to the meter so I was hopeful.. but I am unable to measure the surge current at compressor start up .. but it is higher than what the inverter can provide either the HV battery can not keep up fast enough or the inverter max 2KW is a lie or the jolt is even higher than that ...

Run cable box, TV a few lights for an hour so no problem ICE coming up only once ... but that was just about 200-250 W ... so I am confident I can keep internet TV radio and cell phone charging running ...

So my experience is that this setup is only for low load no rush current ready.

at the above load there was no warming up of the anderson or any other 12V junction....

At this point I doubt my boiler will run either ... the water pump must have some surge current ... but at this point I can not test that ...

Any questions ???

Cheers

 

My experience is the inverter 'surge' is only for a couple of hundred milliseconds but motor startup takes 1-2 seconds. The sustained inverter power and battery surge current has to be large enough for the motor spin-up.

You might be power limited by the 80A fuse. I've tested with a 120A, 12V circuit breaker so you might consider trying a similar sized fuse. Back of the envelope, this will give a 100W or so for additional surge energy. But a refrigerator compressor is a worst-case load. As the compressor motor turns, it develops a back-pressure that really spikes the current load while it is trying to spin up.

You have done good!

Measuring motor startup current normally requires an oscilloscope but a credible version can be configured using a fractional ohm resistor, 0.10 ohm or lower, and audio isolation transformer. Using Audacity to record the output from the audio isolation transformer, calibrate it with a known load, say a 100W light. This is how I measure surge duration and inrush currents:

The fractional ohm resistor goes between the two outlets as you can see in the photo. The isolation transformer connects one side to the resistor and the other side connects to a miniature jack. All of these parts are stock at Lowels and Radio Shack.

With a 10A current:

• 0.1 ohm -> 1V, 10W (kinda big but a single part)
• 0.05 ohm -> 0.5V, 5W (put two 0.1 ohm resistors, 2.5W are larger, in parallel)
• 0.033 ohm -> 0.33V, 3.3W (three 0.1 ohm resistors, 1W or larger, in parallel)

In my case, a local electronics store had even smaller ohm resistors, "current sense" resistors. The power needed is given by (I**2)*R, 10A -> 100A*2, so lower resistance is better. The 1-to-1, audio transformer prevents any ground loop issues and isolates the high voltages so there is no safety risks.

This can measure the duration of inrush current and quantify the size of inverter needed for any load.

Bob Wilson

 

Just a thought, maybe the capacitor is weak If its 10 years old, or even replacing with a bigger capacitor to take more load off the inverter during startup.

Alan.. Sent with Tapatalk 2

 

One early in-rush problem was with the PowerBook, power supply. Like many switching power supplies, they use a diode bridge to charge a capacitor. This initial in-rush can trip the inverter:

The power supply then does a 'slow start' but the diode-cap in-rush has already tripped the inverter.

So I used an in-rush thermistor:

The in-rush thermistor has a higher, cold resistance, so it takes several cycles to charge the cap. Later when the power supply ramps up, the thermistor heats up and the resistance drops. It has to stay hot for the low resistance but spreading out the cap charge doesn't trip the inverter. But this won't work on induction motor spin-up.

Bob Wilson

 

I don't have scope or any of the other hardware Bob uses for measuring inrush magnitude and duration, just a lowly Kill-A-Watt.

My small chest freezer (ca. 1989) normally runs at 160-140W, 1.75A. After unplugging it off long enough to ensure the thermostat had closed, then plugging it back it, the first number to go by on the Kill-A-Watt display was 9.6 amps.

The much newer refrigerator (2011) takes about the same running power, but I didn't do an inrush check while it was slid out and on an extension cord.

 

There's little doubt that the Prius engine driving MG2 makes for a more efficient generator setup than pretty much any air-cooled engine. But, after all, we are talking about an emergency setup, so efficiency is hardly the primary consideration. For us, using a car as a power source is no more useful than a roll-around unit, because if it doesn't automatically operate while we're gone (heat, sump pump), it's useless to us.
When I was reading up on emergency generators, I learned about using a hybrid + inverter to do it, but in the end we purchased a Generac 5871 10KW standby unit that runs off the big 1K gal. propane tank in the back yard. Had it installed for a year and a half now, and all is well.

NB: In putting anything like this together, it's obvious that there are people on this thread who are very well versed in electricity and how to work with it safely. If you're not 100% sure you can, have your setup done professionally. I have done all kinds of wiring 120 / 240V household circuitry, and absolutely to code.....but when it came to installing our standby generator, we hired the electrical contractor who has always done our work to put it in.

 

There was an article in the New York Times a few years ago about using the Prius as a generator. They allow reader comments on their site, and the article gathered over 200, good, bad, true, false, and goofy. (My comment, whose content I don't recall, but was certainly in one of those categories, turned out to be #75.) At that time I thought to read the comments and distill them, Snopes-like, into a summary. I just recalled having done that, and found the link:
Arguing Over PriUPS
It looks like the original comments are still on the Times site if you're even more of a gluton for controversy.

Richard

 

Apparently, there is now an option to make the PiP into an emergency generator: Toyota Prius' New Function Supplies Electricity to Home Appliances -- Tech-On!

I wish that there was more technical information. Based on the supplied picture of the plug, the cable seems inadequate, but comparable to an extension cable for common low- to medium-load current draws.

 

Looks like up to 1500 watt capacity, I'm guessing #12 guage wire. "20 amp"

Alan.. Sent with Tapatalk 2

 

That's my guess too.

 

1500W 20 amp almost surely not work ... I am talking from experience... I am using 4awg on the 12V side and there is NO way you can get 20A .... love someone contradict me but not from the car 12V ports ...

Better chance from the HV side ... there ..1500W is a maybe .... (since Toyota is offering it I guess that should be OK) but current setup 100A fuse and nominal 14.6V ... suggest no way you can get that ...

so if you can tap from the 200+ volt side of the battery ... you possible can get some higher power ... but I would be surprised 2KW or anything that much ...