Prius Backup Generator

[Andy R]

I just read Prius: It’s Not Just a Car, It’s an Emergency Generator - Green Inc. Blog - NYTimes.com which I thought was a kind of interesting use of the Prius. Here is a snippet:

Said Mr. Sweeney, in an e-mail message to The Press: “When it looked like we were going to be without power for awhile, I dug out an inverter (which takes 12v DC and creates 120v AC from it) and wired it into our Prius.” According to the newspaper, “the device allowed the engine to run every half hour, automatically charging the car battery and indirectly supplying the required power.” (The Times reported on a similar venture last year.)

In the future we might be able to utilize our portable power supplies (cars) to backup critical loads in our house. I dig the idea of having power that I can take with me and then use it in various ways.

 

[travelover]

Costco recently had a nice 1000 watt Xantrex inverter in the store for $30. I had purchased this for use with my Escape hybrid at $65 and thought I got a deal.

Because the DC-DC inverter (replaces the alternator of a regular car) is so expensive on hybrids, I made an adapter that limits the inverter to contributing 100 amps when the inverter is attached to the 12 v battery.

When the power is out , I can run lights, computer, etc off the hybrid. It starts itself as needed to recharge it's batteries, then shuts off. It is much quieter than my 4000 watt generator, but will not run my furnace motor.

 

[Jeb-NY]

Finally a reason to buy a hybrid

Great idea.

Jeb

 

[RonBoyd]

Yeah, but... It is much more complicated than that... There are inverters and there are inverters. I am , certainly, not the one to be speaking to this issue because the main thing I know about electricity is I should leave it alone. I do know, however, that there is something call "Pure Sine-wave" electricity created during the 12v to 115v conversion in higher quality Inverters. This type of energy is not the same as created by the $30 Inverter. Non-pure sine-wave may work on a laptop, for instance, (and I say "may" cautiously) but will ruin any device with a motor. The other issue is an Inverter that will generate (if that's the right word) wattage sufficient to say run a coffee maker is very expensive -- in excess of $500-$600.

Anyway, I am sure I have explained this poorly but I am just saying that there is a lot more than meets the eye here.

 

[Bestwifeever]

Not an engineer here but these kinds of stories are interesting. I thought I had seen some earlier gizmo that would let you run electrical appliances off even your non-hybrid car's cigarette-lighter, with the engine running--not that that would be terribly efficient or probably even safe.

The story in the OP is amazing, especially considering the town is in Massachusetts and he got enough power in a winter storm from his Prius for cheap--here is a quote from it:

The newspaper reports that John Sweeney, a resident who lost power, “ran his refrigerator, freezer, TV, woodstove fan and several lights through his Prius, for three days, on roughly five gallons of gas.”

Three days of electricity for five gallons of gas? Wow. I wonder what the effect on the car was, if it shortened the battery's lifespan?

 

[Rich_by_the_Bay]

Costco recently had a nice 1000 watt Xantrex inverter in the store for $30. I had purchased this for use with my Escape hybrid at $65 and thought I got a deal.

Because the DC-DC inverter (replaces the alternator of a regular car) is so expensive on hybrids, I made an adapter that limits the inverter to contributing 100 amps when the inverter is attached to the 12 v battery.

When the power is out , I can run lights, computer, etc off the hybrid. It starts itself as needed to recharge it's batteries, then shuts off. It is much quieter than my 4000 watt generator, but will not run my furnace motor.

Are you saying that it is not OK to buy the inverter, plug it into the 12 volt cigarette lighter and run an extension cord from the inverter to house? Do you need the 100 amp cutoff?

Interesting option...

 

[travelover]

Are you saying that it is not OK to buy the inverter, plug it into the 12 volt cigarette lighter and run an extension cord from the inverter to house? Do you need the 100 amp cutoff?

Interesting option...

Rich, to get the full 1000 watts you really need to attach to the battery as opposed to using the cigarette lighter. You can plug a smaller inverter (say 12 volts x 30 amp fuse = 360 watts) into the lighter socket. In either case I just use an extension cord to the house. The Prius may have it's own fuse to protect the DC-DC inverter. I added the 100 amp fuse to my Escape as a precaution, as these inverters are extremely expensive. This has been widely discussed on Prius chat forums, so the existence of a fuse would have been discussed there.

The comment about modified sine wave vs full wave is correct. A full sine converter will cost much more, but is certainly preferred. For my usage, I'm happy with the modified sine.

 

[Leonidas]

Somewhere in the two articles it was mentioned that the UPS setup that was used to power a refrigerator, freezer, some lights, etc., cost about $2,000. However, in the next sentence the owner said he could do something similar for as little as $200. The differences were not explained.

 

[RonBoyd]

Okay, perhaps this will help:

A 30-page "basic" tutorial by Phred Tinseth.
A tutorial on Inverters by Phred Tinseth
A short article by the Boat Owner's Association of the U.S.
A Prosine 2.0 Inverter/Charger -- Marked down to only $1,959

 

[RonBoyd]

Are you saying that it is not OK to buy the inverter, plug it into the 12 volt cigarette lighter and run an extension cord from the inverter to house? Do you need the 100 amp cutoff?/quote]

This from the June/July 2002 edition of Home Power magazine may help explain:

A number of areas must be considered in connecting to
the grid safely. The utility company should be notified
and their technical and administrative requirements
addressed. These requirements will vary widely from
utility to utility. Permits and electrical inspections may be
required. In harmony with the utility requirements, the​

National Electrical Code (NEC)​

​

​

​

​

, and any local code and
inspection requirements, you will have to plan, select,
and install the hardware that will be used to get from the
inverter to the point where the AC power interfaces with
the existing wiring in the building.
​

The Utility Disconnect
​

In most locations, the connection to the existing wiring
will be through a backfed circuit breaker in an existing
load center. However, some utilities, but not all, require a
disconnect switch that is accessible to utility personnel
between the output of the utility-interactive inverter and
the connection to the existing wiring. If the inverter is to
be mounted inside the building, the wiring from the
inverter to that backfed circuit breaker must be routed
outside the building, through this disconnect, and then​

back inside the building to the load center.

Access to the full 4-page PDF file is by subscription only -- although I don't beleive there is a charge for a subscription. But if you are truly interested in producing your own electricity (by windmill, for instance), the article is pretty thorough and a good place to start.

 

[travelover]

Somewhere in the two articles it was mentioned that the UPS setup that was used to power a refrigerator, freezer, some lights, etc., cost about $2,000. However, in the next sentence the owner said he could do something similar for as little as $200. The differences were not explained.

The difference is that the $2000 set up uses its own DC-DC inverter to directly take high voltage power off the big drive battery in the hybrid and charge a commercial uninterruptable power supply with its own battery bank. This provides very clean power, and a lot of it, and can be wired into the house wiring grid. By tapping in here you basically get to use the full power of the hybrid generator, which is enough to run a whole house. The $200 solution is more like what I described and just pulls off a small portion of the total available power.

 

[OAG]

I never used it but I have a 115V plug in my LEXUS SUV that will run some stuff with the motor running. I am not sure how much (AMPERAGE) power comes out of the thing but I assume it is an INVERTER.

 

[travelover]

I never used it but I have a 115V plug in my LEXUS SUV that will run some stuff with the motor running. I am not sure how much (AMPERAGE) power comes out of the thing but I assume it is an INVERTER.

Your car basically has one of these: Amazon.com: Cobra CPI 130 150 Watt 12 Volt DC to 120 Volt AC Power Inverter: Electronics nicely packaged into the interior trim. They are handy for small appliances like laptops, etc.

 

[OAG]

Your car basically has one of these: Amazon.com: Cobra CPI 130 150 Watt 12 Volt DC to 120 Volt AC Power Inverter: Electronics nicely packaged into the interior trim. They are handy for small appliances like laptops, etc.

Thanks, funny if I do use the plug it will be for a laptop or a phone charger. Appreciate the information - could not locate it any place else.

 

[ERD50]

Extremely poorly written article - just more hybrid hype

I saw that, and it gives the wrong impression that you somehow need a hybrid vehicle to do this.

You do not. He has the inverter hooked to the 12V battery - every car has one of those, so you really could do this for any car. In fact, this is pretty much what I have for my sump pump. A 12 V battery, hooked to a 2500Watt inverter ($200). I have it hooked to a smart charger to keep it topped off, but for an extended outage, I could run jumper cables from my car to the battery, or just hook the inverter directly to the car battery. I could plug a fridge or other appliances into the inverter, which is why I went this route instead of a straight battery run sump pump. Just more flexible. For the same reasons.

The only advantage the Prius might have (could not really tell, but the article mentioned it, sort of), is if it started itself automatically when the 12V ran down.

Andy R said:

In the future we might be able to utilize our portable power supplies (cars) to backup critical loads in our house. I dig the idea of having power that I can take with me and then use it in various ways.

Well Andy, you should be happy, the future was here a couple years ago! And it didn't wait for a hybrid car!

-ERD50

 

[travelover]

I saw that, and it gives the wrong impression that you somehow need a hybrid vehicle to do this.

<snip>

The only advantage the Prius might have (could not really tell, but the article mentioned it, sort of), is if it started itself automatically when the 12V ran down.

<snip>

-ERD50

The hybrid has one slight advantage in that the big battery (that drives the car) can charge the little battery (that you have the inverter hooked up to) until it, too gets too discharged. Then the engine starts up and recharges both batteries. So you get to use the capacity of a fairly large battery in addition to the automatic restart advantage.

 

[ERD50]

The hybrid has one slight advantage in that the big battery (that drives the car) can charge the little battery (that you have the inverter hooked up to) until it, too gets too discharged. Then the engine starts up and recharges both batteries. So you get to use the capacity of a fairly large battery in addition to the automatic restart advantage.

OK, *that* makes sense to me. "Slight advantage" - OK ( maybe even rates as a considerable advantage, depending on circumstance), but that article makes it sound like this is some amazing new thing that was unattainable until the Prius arrived.

QUESTION: What mode is the Prius in where it can restart when the battery gets low? I would think there could easily be many hours between starts (all depending on your power draw) - I would think there would be some safety concerns about a car being able to auto-start hours later?

But that got me thinking - they make those after-market remote starters for standard cars. A clever company could set one of these up to allow the same kind of mode where the car starts when the 12V battery hits X volts, so it would recharge. BTW, the 12V inverters normally shut off and stop drawing power once they hit 10.2V on the battery. Voltages below that are hard on the battery. I'm pretty sure mine has a low batt warning that kicks in earlier.

edit/add - googled and found this in afew seconds:
http://www.truckaddons.com/Catalog/subpages/designtech01.htm

Prevent a dead battery. Our built-in low battery voltage start option continually monitors and recharges your vehicles battery if necessary.

Now the Prius might go longer between starts with the bigger battery, but when we are talking emergency situations, seems like a pretty minor issue.


-ERD50

 

[RonBoyd]

A clever company could set one of these up to allow the same kind of mode where the car starts when the 12V battery hits X volts, so it would recharge.

This would be similar to the "auto-start" that high-end RV's use. Cummins Onan introduced, last month, a Energy Command AutoStart as an add-on to most of their diesel, gas and LP generators.

This device provides "Detection of Shorepower so the EC-30W will only start the generator if shorepower is NOT present and batteries get low or the RV gets too hot. This allows the RVer to use the EC-30W as a back-up to shorepower in campgrounds with weak or intermittent power" and "Remotely starts and stops a generator from up to 100 ft away."

The future may already be here.

 

[travelover]

OK, *that* makes sense to me. "Slight advantage" - OK ( maybe even rates as a considerable advantage, depending on circumstance), but that article makes it sound like this is some amazing new thing that was unattainable until the Prius arrived.

The big deal with a hybrid is that 15,000 watts is potentially available. But, you need to cleverly tap into the high voltage battery directly to access this, otherwise you are messing with 1000 - 2000 watt 12 volt inverter.

QUESTION: What mode is the Prius in where it can restart when the battery gets low? I would think there could easily be many hours between starts (all depending on your power draw) - I would think there would be some safety concerns about a car being able to auto-start hours later?

It is in a running mode in park. I'm not sure of the Prius strategy, but my Escape hybrid has to keep the catalysts up to temperature, so down time would probably be measured in minutes. Safety, schmafety, we're having fun here.

But that got me thinking - they make those after-market remote starters for standard cars. A clever company could set one of these up to allow the same kind of mode where the car starts when the 12V battery hits X volts, so it would recharge. BTW, the 12V inverters normally shut off and stop drawing power once they hit 10.2V on the battery. Voltages below that are hard on the battery. I'm pretty sure mine has a low batt warning that kicks in earlier.

Another advantage of the hybrid, it would never let the lead acid (12 volt) battery get that low.

edit/add - googled and found this in afew seconds:
Truck Add Ons DesignTech Remote Start


Now the Prius might go longer between starts with the bigger battery, but when we are talking emergency situations, seems like a pretty minor issue.


-ERD50

Lighten up ERD50, we spent all this money on a hybrid and we are gonna have fun with it even if it breaks us!

 

[ERD50]

Lighten up ERD50, we spent all this money on a hybrid and we are gonna have fun with it even if it breaks us!

Is that like: I'd give my right arm to be ambidextrous?

My only real gripe is with the 'journalism' in articles like this. Like the ones that say getting a solar cell charger for your iPod or cell phone is 'being green'.

-ERD50

 

[samclem]

Some municipalities are buying hybrid buses and plan to use the vehicles as mobile emergency generators for use at schools and other central emergency sheltering areas when there is a mass power outage. Apparently a single bus can provide a lot of juice, at least as long as they have diesel fuel. Of course, all the buses used for this aren't carrying people around the city, but it does sound like a useful option. Compared to a dedicated emergency generator, the bus is probably more likely to actually run when you need it, and will be less expensive overall.

 

[TromboneAl]

Practical info: We use the inverter on our car, through the cigarette lighter, when the power goes out. I use it only for powering a fluorescent light for reading or cleaning up the kitchen, or the fan (on low: 20 watts) that distributes heat from the woodstove (actually a woodstove-type fireplace).

This has worked well, and the battery has never discharged enough that the inverter shuts off (which it will do so that the battery is always strong enough to start your car).

 

[travelover]

Some municipalities are buying hybrid buses and plan to use the vehicles as mobile emergency generators for use at schools and other central emergency sheltering areas when there is a mass power outage. Apparently a single bus can provide a lot of juice, at least as long as they have diesel fuel. Of course, all the buses used for this aren't carrying people around the city, but it does sound like a useful option. Compared to a dedicated emergency generator, the bus is probably more likely to actually run when you need it, and will be less expensive overall.

That's a pretty cool idea. What modern, forward thinking company make these buses?

First GM Hybrid Transit BusesGo to Work - MSN Autos

 

[youbet]

Some municipalities are buying hybrid buses and plan to use the vehicles as mobile emergency generators for use at schools and other central emergency sheltering areas when there is a mass power outage. Apparently a single bus can provide a lot of juice, at least as long as they have diesel fuel. Of course, all the buses used for this aren't carrying people around the city, but it does sound like a useful option. Compared to a dedicated emergency generator, the bus is probably more likely to actually run when you need it, and will be less expensive overall.

Did they mention what technology they'll use to convert the battery DC into 110/220 AC? I can't imagine an inverter capable of handling a school or emergency shelter.

 

[RonBoyd]

Did they mention what technology they'll use to convert the battery DC into 110/220 AC? I can't imagine an inverter capable of handling a school or emergency shelter.

The key word in the statement was "generate." An inverter doesn't "generate" electricity, it only converts. The real question is: Is the bus's generator putting out 12v or 115v electricity? Another important question would be about the wattage. It seems to me that a generator large enough to provide enough useful electricity to do more than run low-wattage light bulbs would be pretty expensive... not to mention quite heavy. But, again, I am way out of my league here.