Author Topic: Thoughts on using a Hybrid Automobile as a power system for cabin  (Read 10236 times)

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DanMc

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As I think through the electrical system at my cabin up in Conway, NH, I'm trying to explore all options for powering an off-grid camp.  I don't need all that much power since everything up there (except a shallow well pump) is set up to run on propane. 

Some people have reported that a Toyota Prius makes an excellent power system for an off-grid application.  The biggest issue is bringing the high voltage DC down to the typical 110/220 volt AC.  These people seem to have solved this problem, and sell inverter kits to adapt to a Prius for just this application.   
http://www.converdant.biz/plug-out/

Anybody have any experience or opinion on this?

Thanks,
Dan

dnix71

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Re: Thoughts on using a Hybrid Automobile as a power system for cabin
« Reply #1 on: June 26, 2015, 03:23:55 PM »
I wouldn't do it. Mess up and you have no ride out. Buying a Prius battery pack used/rebuilt and using that for cabin power is a different matter.

electrondady1

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Re: Thoughts on using a Hybrid Automobile as a power system for cabin
« Reply #2 on: July 02, 2015, 05:33:09 AM »
Ive read several scenarios  about future systems were your car and home are tied into a single system and all part of a smart grid.even if the battery's are flat couldn't you use the gas motor to get up and running ?

madlabs

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Re: Thoughts on using a Hybrid Automobile as a power system for cabin
« Reply #3 on: July 04, 2015, 08:58:45 AM »
Go they have a starter motor with it's own battery or does it use the electric motor and the big battery to start the engine? I suspect the latter. If so, I'd want to figure out a jump start situation just in case. Do they make manual transmission for those and can ya do a rolling start?

Other than making sure you can fire up the rig it sounds great.

Jonathan

Frank S

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Re: Thoughts on using a Hybrid Automobile as a power system for cabin
« Reply #4 on: July 04, 2015, 07:57:46 PM »
MadLabs; I would think that if the system had a disconnect if the battery voltage fell to minimum engine start, or was similarity connected to the automatic engine start circuit it might be viable   
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Simen

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Re: Thoughts on using a Hybrid Automobile as a power system for cabin
« Reply #5 on: July 05, 2015, 12:25:15 AM »
I'd guess it has its own 12V start battery.

I have an old '00 Citroen Saxo Electrique (all electric), and it has its own 12V battery for running the controller, lights etc. That 12V battery are charged from the main 120V, 100Ah battery bank with a DC-DC inverter (1kW, i think), and i'd think the hybrids do the same.

The prius has a 288V, 6Ah bank, it seems. (depending on the model)
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DanMc

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Re: Thoughts on using a Hybrid Automobile as a power system for cabin
« Reply #6 on: July 07, 2015, 10:21:47 AM »
I spoke with Randy Bryant over at Converdant, the guy that sells these inverters, and also spent some time looking at the Prius. 

When used as a power system, the Prius will cycle the engine on and off as needed to maintain the propulsion battery pack.  There is no concern about draining the batteries down since the car manages that on its own.  Sitting at idle, the Prius is spec'd to provide 3000 watts continuous, and the engine will run as needed to maintain proper charge in the batteries.  For this it it necessary to have the car "on".  That is, you press the "start" button and the car wakes up but doesn't do anything other than provide power since you leave it in Park.  Once turned on, the car does not "time out" and shut itself off automatically like a lot of electronic devices do. 


madlabs

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Re: Thoughts on using a Hybrid Automobile as a power system for cabin
« Reply #7 on: July 08, 2015, 05:41:11 PM »
Sounds like a good deal. All you need is a solar charge controller that can do a 120VDC bank. I think I have read that you can use to MX60's to do that and there are probably other options. I also think I might have seen something about a "kangaroo" version of the Midnite made for Australia or New Zealand. That's what I'd want.

Once you can use solar yer set! It certainly sounds cool in the anti-theft area, you drive away with all the expensive stuff when you leave.

Do you have the Prius already?

Jonathan

DanMc

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Re: Thoughts on using a Hybrid Automobile as a power system for cabin
« Reply #8 on: July 09, 2015, 10:18:48 AM »
I don't have a Prius yet.  I'm still doing my homework. 

DanMc

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Re: Thoughts on using a Hybrid Automobile as a power system for cabin
« Reply #9 on: July 20, 2015, 07:04:56 AM »
An update on this topic:

Last week I picked up a used 2010 Prius.  It did a fantastic job of replacing the 1000 watt generator previously used for charging the batteries.

Test #1:  Initially a 30 foot length of 14 gauge wire was plugged into one of the Prius 12 volt accessory connectors.  This was directly tied to the cabin batteries (4 - 6 volt Trojian T105's connected to run at 12 volts).  With the batteries sitting at 12.5 volts, and the Prius sitting at 14.1 volts, I measured 1/2 amp charging the cabin batteries.  Not too exciting.  I think that this is about what the 45 watt solar panel will do. 

Test #2:  Next I used a 25 foot length of 4 gauge wire I picked up on ebay, with an 80 amp in-line circuit breaker.  Terminals were crimped on each end.  I wanted to put an Anderson connector in there so I could readily disconnect things, but I didn't have a crimper for these huge contacts.  So these cables were wired directly from the Prius 12 volt battery directly to the cabin batteries with the fuse in there.  With these wires, 2.5 amps were measured going into the cabin batteries.  With this configuration, the cabin was powered most of the weekend.  The batteries charged up to 14.1 volts.  At one point I saw them up at 14.4, which was surprising to me because I read that the Prius will only charge up to 14.1.  I'm not sure, but it may be possible that the solar panel was pulling it up higher.  For a while I tripped the circuit breaker and shut down the Prius out of fear that I may be overcharging the batteries.

There was one thing that I did not expect.  I almost lost the Prius to my wife, who drove separately and wanted to stay longer.  She insisted that I leave the Prius behind so she wouldn't have to run the generator.  Fortunately I had an excuse:  "But honey, then you'd have to take a wrench and disconnect those scary wires from the Prius battery and in the process, they might even create some sparks!"  That worked!!

Next time I'll have to come up with a better excuse, or start looking into a hybrid for her, or a bigger solar panel so we can maybe eliminate the need for a generator entirely!!!!


madlabs

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Re: Thoughts on using a Hybrid Automobile as a power system for cabin
« Reply #10 on: July 20, 2015, 12:07:19 PM »
Very cool! 2.5 amps AKA 30 watts is pretty slow charging. Y'all must be pretty conservative on the power use. Too slow if you use much power.

Keep us informed, very interesting project.

Jonathan

DanMc

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Re: Thoughts on using a Hybrid Automobile as a power system for cabin
« Reply #11 on: July 21, 2015, 07:44:49 AM »

Electric power consumption is very low.  All the lights in the cabin are LED.  All the typical appliances (fridge, cooking stove, water heater) run on propane. 

The only big load is the shallow well pump, but that still runs on the big generator since the 1000 watt inverter couldn't power that.  Moderate loads are the 5000 BTU A/C and ceiling fans, and I have run the small 1000 watt Honda generator to power those with no issue.  I have not attempted to run those on the inverter yet. 

By upgrading to a 2000 watt inverter, then I should be able to eliminate the need to run the big generator for the pump.  I would expect that under a heavier load, that the Prius would be delivering more than 2.5 amps.  Will be interesting to see how much charge it sucks out of the batteries.  Each time the pump is run it goes for about 20 minutes because there are 3 big well tanks that hold a lot of pressurized water, so it only needs to be run once a day.  I'll be sure to measure the current supplied by the Prius when running the pump on the batteries.  That won't happen for a few weeks.

taylorp035

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Re: Thoughts on using a Hybrid Automobile as a power system for cabin
« Reply #12 on: August 12, 2015, 09:54:41 AM »
Is there some kind of charger built into the Prius to charge the accessories battery from the propulsion battery?  Or is the starter battery only charged from the engine/alternator?  If you could actually manage to pull a few thousand watts from the accessories battery, then a nice high powered RC battery charger could increase your transfer rate to the cabin if you needed more than 2.5 Amps.

I think this kind of setup will be easier in the future (for the average consumer) once a good vehicle to grid system comes out.

DanMc

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Re: Thoughts on using a Hybrid Automobile as a power system for cabin
« Reply #13 on: February 25, 2016, 11:11:20 AM »
Hello!
I'm checking back in to give an update on my progress, and to see if there's anybody else doing this.

Yes, the Prius has a charger that runs from the big propulsion battery to the little 12 volt battery.  The car monitors the propulsion battery and runs the engine as needed to keep it sufficiently charged. 
 
Throughout last summer I used my Prius to power our cabin.  I tied the 12 volt battery from the Prius directly to my bank of 4 Trojan T105 6 volt batteries.  The batteries are configured as pairs in series to get 12 volts.  I used about 25 feet of #4 wire with an Anderson connector so I can easily connect/disconnect the car from the cabin.  I have an 85 amp in-line breaker so there's something safe to pop if something gets shorted. 

This works nicely because I didn't have to change much of anything since I just operate the cabin as if I'm running on the batteries, and the Prius is there to keep them from discharging.  I just had to wire the #4 wire to the battery bank and add a connector with a short stub of wires to the 12 volt battery on the prius.  The Anderson connector is about a foot from the Prius 12 v battery and it tucks nicely into the storage area under the cargo floor in the car. 

I have completed the upgrade to a 2000 watt inverter and found that I cannot get the pump to start.  The issue (I think)  is that the prior owner wired in the batteries using something like #8 wire.  When I try to start the pump, the inverter just kicks out and I'm sure it's due to voltage drop in those wires.  I picked up some 0 AWG wire to replace the #8 when things start to warm up a bit this spring. 

So with this setup, here's how it works:
Drive the Prius up close to the electrical bay.  Pull the cable out, lift the rear hatch of the car, lift the floor panel and plug in the big connector.  Go inside and close the inline 85 amp breaker.  Go inside the car and press the PWR button to wake up the car.  Make sure all electrical loads in the car are turned off.  The Prius will sit there quietly minding its own business.  It will run the engine when it feels like doing so.  With my minimal loads of things like LED lights and some ceiling fans, the Prius will start the engine about every 40 minutes.  The engine will run for about 90 seconds and then shut down.  Over 3 days it will consume about 2 gallons of fuel.  During this time I don't have to give much consideration about having extra lights on or anything like that.  It's like I'm on the grid - power all the time with virtually no noise.

I still have to switch the cabin AC power feed over to the big generator whenever I need to run the water pump, but hopefully I won't need to do that once I get the T105's wired in with the 0 AWG wire.

The next big step is to add some solar panels to keep the batteries charged when I don't have the Prius there!!!!



Bruce S

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Re: Thoughts on using a Hybrid Automobile as a power system for cabin
« Reply #14 on: February 25, 2016, 02:07:23 PM »
DanMC;
NOT doing this but following along.
The pump starting versus the inverter >>> Is this a MSW inverter? there have been issues in the past with this sort of thing, including but limited to people trying to run a fridge from an inverter. It could be the pump's motor doesn't play well with that inverter.
Just a thought.

PS>> I have a neighbor that has a Camry Hybrid , I will tell him of your spiffy solution!!

Cheers
Bruce S
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madlabs

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Re: Thoughts on using a Hybrid Automobile as a power system for cabin
« Reply #15 on: February 25, 2016, 02:54:08 PM »
Sweet! Thanks for the update. Now if only I had a Prius and a cabin...

Jonathan

EDIT: Oh, and I think you are probably right about the cables being too small. Wouldn't surprise me a bit, in fact I'd be surprised if they weren't a problem.
« Last Edit: February 25, 2016, 02:59:18 PM by madlabs »

DanMc

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Re: Thoughts on using a Hybrid Automobile as a power system for cabin
« Reply #16 on: February 25, 2016, 06:54:17 PM »
The new 2000 watt inverter is a pure sine unit. 

I can post some pics in a few weeks (next time we are up there)  if anybody is interested. 

plasmahunt3r

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Re: Thoughts on using a Hybrid Automobile as a power system for cabin
« Reply #17 on: February 27, 2016, 05:29:38 PM »
Regarding the Inverter failing when the pump kicks in.  Try mounting a 1-2 Farad Capacitor on the 12v Trogens.  Pumps and Refrigerators draw a large current starting and the capacitors will handle that Starting Load.  You can find the capacitors in the car audio section of stores like Walmart or buy on Ebay.

dnix71

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Re: Thoughts on using a Hybrid Automobile as a power system for cabin
« Reply #18 on: February 28, 2016, 06:33:16 AM »
Regarding the Inverter failing when the pump kicks in.  Try mounting a 1-2 Farad Capacitor on the 12v Trogens.  Pumps and Refrigerators draw a large current starting and the capacitors will handle that Starting Load.  You can find the capacitors in the car audio section of stores like Walmart or buy on Ebay.

I had a window a/c in my van run from an inverter and it took two capacitors to make it work. One boost cap on the a/c itself and a 58 Farad cluster mounted on the inverter. A 1000 watt sine inverter would start and run a window a/c that pulled about 500 watts running.
When the van engine died I took the inverter off before scrapping the van and installed it on the next vehicle, a Toyota Corolla. Yesterday I carried out the a/c and confirmed the arrangement still works, even though the a/c will not be mounted on the Corolla. The Corolla has an aftermarket 130 amp alternator, too. Plenty of mobile power now.

DanMc

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Re: Thoughts on using a Hybrid Automobile as a power system for cabin
« Reply #19 on: March 02, 2016, 10:42:18 AM »
Regarding the Inverter failing when the pump kicks in.  Try mounting a 1-2 Farad Capacitor on the 12v Trogens.  Pumps and Refrigerators draw a large current starting and the capacitors will handle that Starting Load.  You can find the capacitors in the car audio section of stores like Walmart or buy on Ebay.

That's an excellent idea.  When I rewire the batteries with 0 AWG, I'll add one of these suckers directly to the inverter terminals.  Look out if something ever shorts them out. 

go4it

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Re: Thoughts on using a Hybrid Automobile as a power system for cabin
« Reply #20 on: April 08, 2016, 04:23:31 PM »
I like the idea of using a hybrid auto as an automatic start generator.  Maybe I could get a damage insurance write off and park it near the cabin as a lawn ornament and automatic start generator.  I am a little concerned about the engine having to start and charge the batteries so often.  What voltage are your batteries at when the car decides to recharge them?

Frank S

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Re: Thoughts on using a Hybrid Automobile as a power system for cabin
« Reply #21 on: April 08, 2016, 06:18:26 PM »
I like the idea of using a hybrid auto as an automatic start generator.  Maybe I could get a damage insurance write off and park it near the cabin as a lawn ornament and automatic start generator.  I am a little concerned about the engine having to start and charge the batteries so often.  What voltage are your batteries at when the car decides to recharge them?
I would think that since those hybrids are more or less designed to have the engine start whenever the load is too great for the batteries while driving it would be no different using one as a power on demand generator.
 Also constructing an inverter that can accept the hybrid's battery voltage on the DC side with a transformer like in the Oztulles inverter would make for a dynamite package for long term use Just add a solar array string with the same high voltage output should yield a system that would be nearly trouble free for a decade or more
 
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DanMc

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Re: Thoughts on using a Hybrid Automobile as a power system for cabin
« Reply #22 on: June 03, 2016, 10:58:37 AM »
I'm back with another update on this thread.  As you may recall, last summer I tied the 12 volt battery in my 2010 Prius to the 4 Trojan T105's in my cabin.  The Prius did a wonderful job keeping the batteries up to charge. 

Now things have changed.  I just returned from installing two Trina 250 watt solar modules on the roof, feeding a Midnite Classic 150 charge controller to charge the batteries.  I don't think that I'll ever hook up the Prius again!  Now I finally have a system that will properly charge and equalize the batteries. 

I also rewired the batteries to replace the 8 AWG wire, installed by the prior owner, with 1/0 wire.  Not only did he use crappy wire, but he didn't do anything to try to keep the wires as short as possible.  Now with the heavier wire, and kept to shortest possible lengths, it's like I have a whole new power system.  Before this, I couldn't start my bench grinder without tripping the inverter off line.  Now I can run the bench grinder, a 300 watt flood light and a 5000 BTU air conditioner all at the same time, and the inverter is only reporting 980 watts. 

Powering off the Prius 12 volt battery was a super easy and quick way to get power, but even a small solar system is far superior. 


SparWeb

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Re: Thoughts on using a Hybrid Automobile as a power system for cabin
« Reply #23 on: June 08, 2016, 12:49:54 PM »
DanMc,
Followed this story with interest.  Great idea and well executed to the end.  Thank you for sharing.  :)
Now that you have electric power there, the bigger appliances will inevitably follow... 
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DanMc

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Re: Thoughts on using a Hybrid Automobile as a power system for cabin
« Reply #24 on: October 06, 2016, 09:34:34 AM »
Hi Guys,
Another follow-up on my cabin systems.  I have learned so much!!!!!!

I have had the better part of a full summer now running with the 500 watt solar system at the cabin.  Once this was installed, I had no need to ever run the small generator for charging the batteries.  But....  The AC water pump was a problem.  I tried to get that pump to run off the 2000 watt inverter, but it just didn't have enough guts to get it going.  As a result, I was still tied to running the large generator each day to charge up the bladder tanks.  I'm glad that I couldn't get it to work, because that forced me to find an alternative. 

Later on in the summer I found a fabulous 12 volt DC pump made by Shurflo, model 5050.  These pumps are inexpensive (about $150) and work great for a rainwater harvesting system.  So I plumbed in one of these pumps in parallel to my big fat ugly AC pump.  I had a lot of concerns about how this would work, but for $150 it was an fair gamble.  The pump update met every hope I had, and it even runs for less time (about 10-15 minutes) than the old AC pump (I don't understand why that is - maybe the AC pump is half-shot).  From the factory it kicks off at 65 psi and on at about 45.  There's a tiny set screw that adjusts the pressures, so I have it set to go on at about 35 psi and off at 55.  I no longer need to run any generators for anything!!!  The pump sits there and waits for water pressure to drop and starts up on its own.  It makes a comforting purring sound so I can hear it up in the cabin, but it's not disruptive.  The sound is perfect so if something happens (like you run the water tanks dry!!) and the pump runs longer than expected, then you know it needs attention.  That did happen once, but this pump is designed to run dry with no issues.  Power consumption is about 10 amps. 

Now we have a cabin that has the feel of being on the grid.  The solar system keeps the batteries fully charged without any attention whatsoever.  The water system runs without a thought, other than keeping an eye on the water level in the tanks. 

I will never again hook up the Prius to the cabin.  Don't bother trying that.  A 500 watt solar system for about $2K with a DC water pump is the way to go. 


OperaHouse

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Re: Thoughts on using a Hybrid Automobile as a power system for cabin
« Reply #25 on: October 07, 2016, 01:00:50 PM »
Next you will have to try making hot water with the excess PV power.  My camp has about 900W of panels that the excess, after running fridge and other things, goes to making hot water.  I usually can divert 3KW to heating water.  Never have to turn on the propane heater anymore.  Two tanks in series, 10 gallon for fast response and 20 gallon for preheat.