Electric Power from Prius

Actually, there are several owners that have set up the Prius to serve as an emergency generator in case of power failure. You get the power from the traction battery, not the 12-volt (IIRC).

 

<div class='quotetop'>QUOTE(goelectric @ Aug 7 2007, 10:33 PM) [snapback]492260[/snapback]</div>

Yes, the 12V battery is small. Where do you get the rest of this information? What sort of testing have you done?

Welcome to PriusChat! Check the link in my sig for the local Prius/HSD meetup group.

 

<div class='quotetop'>QUOTE(goelectric @ Aug 8 2007, 12:33 AM) [snapback]492260[/snapback]</div>

The NHW20 works like my NHW11:

http://hiwaay.net/~bzwilson/prius/priups.html

The Prius works quite nicely as a 1 kW, emergency generator, and it is quite happy to cycle the engine as needed to sustain the load. It was my first modification and we've used it several times.

Bob Wilson

 

i'm not an expert... but... couldn't you use the's car 12v system. currently, i'm able to run my audio system for roughtly 2 hours on a normal charge in ign on mode. if the battery runs low, things will begin to blink. ( stereo on and off ) There is plenty of power to turn the car on. this recharges the car fairly quickly allowing for the process to repeat. If you hooked a larger 12v up to the cars 12v, you could in theroy use the car as a direct inverter and recharge unit.

 

<div class='quotetop'>QUOTE(V8Cobrakid @ Aug 8 2007, 03:27 AM) [snapback]492278[/snapback]</div>

Just keep the car in "Ready" and "P" and the ICE will come on as needed to recharge the main traction battery. The 12 VDC system is fed by the inverter that operates off of the main traction battery. As long as the car is in "Ready", it will cycle on its own.

Bob Wilson

 

<div class='quotetop'>QUOTE(bwilson4web @ Aug 8 2007, 08:11 AM) [snapback]492311[/snapback]</div>

The only other thing to add is that it would be reasonable to put a fuse in-line to guarantee that you can't exceed a 1 kw draw, so that you don't blow the corresponding 100A fuse in the Prius. I guess that's more for inverter users. If you're just charging a 12v battery, that might not be necessary.

 

Further, the Prius fastidiously maintains 13.8V on the 12V system. So make sure you have a low resistance connection, otherwise you will not charge your other batteries. It's a perfect "float charge" voltage - but at the Prius battery.

As an example, typical "poor" connections with clips will give 0.1 to 0.5 ohm contact resistance. Also don't forget the resistance of the cable. If you are hoping for a 10 Amp charge current, you will loose 1 to 5 volts across that contact resistance, and your batteries will not charge.

A good solution is to make a short cable, using #10 finely stranded copper cable. Put in an in-line fuse 20 to 30 Amp, close to the battery connection point on the +ve wire, and a ring terminal to go under the battery clamp bolt. Crimp and solder the ring terminal, in that order. Do the same for the -ve lead, but you don't need a fuse there. Put a good quality connector on the end of the short cable, and hide it under the hatch floor. It must be female, and make sure the sockets are well shielded from contact with stray metal. Now you can make the other end of your charging cable, again keeping it as short as possible. I recommend charging the batteries on the ground outside the Prius, so 6' or so of #10 finely stranded wire.

When you want to charge the batteries, put the Prius in "ready" with the parking brake firmly applied and the gear selector in "P". Plug in your charging cable. You should be able to get 5-10 Amp of charging current this way.

 

Lest confusion set in, there are only two or three people who have
managed to power inverters off the 200V *traction battery*. Usually
by hooking up old commercial UPSes designed to run on about the
same battery voltage. And they knew what they were doing. The vast
majority of other efforts [including mine] are off the 12V system.
.
_H*

 

IIRC, the inverter system in the Prius would directly invert needed power from the traction battery into the 12V power system for charging your batteries. I remember there is a limit to how much current the inverter can produce at any given time, but aside from that it shouldn't be a problem. So, basically... by charging batteries from the 12V system would be taking inverted power directly from the traction battery which the Prius would monitor and kick on the ICE when needed. I don't think you'll have any problems with it, just remember the Prius can only charge from the ICE when in "Ready" mode (press brake with foot and power on) and it must be in 'Park' (it will not be able to charge from ICE in 'Neutral'). The parking brake and adding a fuse would be a good idea too.

 

I think Bob Wilson's advice is excellent; I've slept in the car and just leave it powered up...why not do the same and charge from it (within reason), too?

 

<div class='quotetop'>QUOTE(bwilson4web @ Aug 8 2007, 08:11 AM) [snapback]492311[/snapback]</div>

:huh:
Say you are in park and in accessory mode, i.e., not in "Ready," running the air conditioner. What happens when the traction battery level gets too low? The car shuts off? AC drains the traction battery and you are in lots of trouble?

To me, those two choices do not make any sense. The choice not listed, i.e., the ICE starts and recharges the battery, makes the most sense.

 

<div class='quotetop'>QUOTE(Wiyosaya @ Aug 8 2007, 02:47 PM) [snapback]492608[/snapback]</div>

While your third option makes the most sense, you told the car to not run the engine by putting it in acc. mode.
So it's not the car with no sense, it's the guy who puts it in acc. mode.

It will shut off before the battery is discharged too far.

 

Goelectric, not sure how many watts you are trying to obtain, but the accessory sockets are not a good way above 100 watts. Hard-wiring directly to the main 12 volt line is the best approach. Bob Wilson's web site gives good details, but I would also suggest a dedicated inline fuse,conservatively rated, to further protect the Prius' electrical system.

 

<div class='quotetop'>QUOTE(goelectric @ Aug 8 2007, 08:32 PM) [snapback]492751[/snapback]</div>

Depending upon the wattage rating, the somewhat inefficient, plug-in inverters have a limited power rating and they can get pretty warm. If they are sitting on a carpeted floor, they can thermally shutdown. When I was using a plug-in inverter in my wife's car, I always made sure there was 'air space' under the inverter to keep it from getting too hot.

GOOD LUCK!
Bob Wilson

 

Uhh, the poster you quoted *did* write "keep the car in Ready", that is, ON, and shifted to Park. That way the engine starts as needed to keep everything charged up. You are quite correct, leaving it in ACC will end in grief when the 12V battery discharges. (To continue the litany of avoidable disasters: leaving it in IG-ON will eventually drain the traction battery; leaving it ON/Ready but shifted into Neutral will also eventually drain the traction battery.)

 

Does anyone know if the "inverter is powered on" or inverting power from the traction pack to the 12V system in the Prius when in Accessory mode? I've never left it in accessory mode long enough to see any bars go down on the traction pack... It may be possible that the inverter isn't powered on at that time in which case only the 12V battery would be drained, but I could be wrong. Either way, you'd be in trouble.

 

<div class='quotetop'>QUOTE(ilusnforc @ Aug 10 2007, 02:10 AM) [snapback]493443[/snapback]</div>

Hmmm, I was all set to respond by saying that the traction battery is not connected unless you are in "Ready" mode, so in both ACC and IGN-ON you will only drain your 12V battery, but will do so quickly because of it's rather limited number of available amp hours.

Then I realized that I thought that was how it worked, but I wasn't certain. Hopefully some one with more certainty and credibility will back me up on this.