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eHam Forums => Emergency Communications => Topic started by: N4UM on June 02, 2012, 04:12:09 PM



Title: Toyota Prius as an emergency power source
Post by: N4UM on June 02, 2012, 04:12:09 PM
I've read several posts on the internet in which people have hooked up 1KW inverters to the 12 volt starting battery on their Toyota Prius hybrids.  That battery is charged from the large 200+ volt propulsion battery in the vehicle.  When the starting propulsion battery volage drops below a certain point, the gasoline engine turns on and recharges the propulsion battery.  The advantage of this system is that the gasoline engine runs only when necessary and consequently burns only about one quart of gasoline per KWH.

I wonder if any readers in this forum have used this sort of system with the Prius or with any other hybrids.  If so, what sort of results have you experienced?


Title: RE: Toyota Prius as an emergency power source
Post by: KC0RZW on June 03, 2012, 07:40:27 AM
The gasoline engine will also run periodically to maintain coolant temperature and air fuel sensor temp,  regardless of the hv battery state of charge.  So it may be efficient on a warm day,  but at 20 below the gas engine is almost constantly running.


Title: RE: Toyota Prius as an emergency power source
Post by: N4UM on June 03, 2012, 01:53:16 PM
The gasoline engine will also run periodically to maintain coolant temperature and air fuel sensor temp,  regardless of the hv battery state of charge.  So it may be efficient on a warm day,  but at 20 below the gas engine is almost constantly running.

Thanks for the info.  I live in Florida where hurricanes are the problem and 20 below seldom happens!


Title: RE: Toyota Prius as an emergency power source
Post by: KC0RZW on June 03, 2012, 04:46:03 PM
Yeah, prius owners get a little upset up here when they only get 30 mpg during the winter.  If I was using a prius for what you are suggesting I wouldn't get too carried away with what you are running,  the 12 volt system isn't designed for constant high current draws.


Title: RE: Toyota Prius as an emergency power source
Post by: N5TWB on June 04, 2012, 12:39:03 PM
Just when I thought the last post decrying the cost of a good Honda inverter-type generator had expired, along comes somebody to suggest a Prius as a power source... :D :D :D

J/K, I couldn't ignore the ironic/silly comparison opportunity. Carry on...have a good day!


Title: RE: Toyota Prius as an emergency power source
Post by: KE4DRN on June 05, 2012, 05:51:47 PM
Won't be long before Harbor Freight starts to sell a clone of the Prius!

73 james


Title: RE: Toyota Prius as an emergency power source
Post by: N2RRA on July 02, 2012, 12:39:48 AM
I should just say "pay them no mind" N4UM.

First off, Ive never tried putting a station far enough away from the Prius to say this statement wouldn't apply but the big problem is the noise from the high voltage lines in the Prius you'll have to worry about.

It causes major high noise floor within the reciever almost rendering it useless. Unless you take certain grounding measure to reduce this noise you'll be fine. I guess in your case depending on your scenerio your still better off with a generator or other power source.

By the way even in the winter the Prius still functions as it does in the summer no prob.

73!


Title: RE: Toyota Prius as an emergency power source
Post by: N4UM on July 02, 2012, 12:13:59 PM
N2RRA - Thanks for the information.  I have a cheap 400 watt inverter that I plan on trying out while running a 75 foot extension cord into the shack.  If the noise is not too bad maybe I'll go ahead and spring for a 1200 watt sine wave inverter. 


Title: RE: Toyota Prius as an emergency power source
Post by: W8JX on July 02, 2012, 03:48:03 PM
N2RRA - Thanks for the information.  I have a cheap 400 watt inverter that I plan on trying out while running a 75 foot extension cord into the shack.  If the noise is not too bad maybe I'll go ahead and spring for a 1200 watt sine wave inverter. 

I would just spring for a 1000 watt generator and be done with it. I would not run my car to power my shack.


Title: RE: Toyota Prius as an emergency power source
Post by: W7HBP on August 21, 2012, 11:41:29 AM
I've read several posts on the internet in which people have hooked up 1KW inverters to the 12 volt starting battery on their Toyota Prius hybrids.  That battery is charged from the large 200+ volt propulsion battery in the vehicle.  When the starting propulsion battery volage drops below a certain point, the gasoline engine turns on and recharges the propulsion battery.  The advantage of this system is that the gasoline engine runs only when necessary and consequently burns only about one quart of gasoline per KWH.

I wonder if any readers in this forum have used this sort of system with the Prius or with any other hybrids.  If so, what sort of results have you experienced?

I am a cetified Toyota Master Diagnostic Technician by trade, same Toyota dealer for the last 24 yrs and I am also hybrid certified. You are correct. The 12V system gets its power from a "converter" from bumping down the voltage for the 12V system from the high voltage battery and the engine will start as needed only. Turn the heater off etc. If the heater is on, it will force the engine to run more.


Title: RE: Toyota Prius as an emergency power source
Post by: NJ3U on October 24, 2012, 06:55:40 AM
I've had the oppurtunity to work the AT Golden Packet event with Bob Bruninga over the last years.  In the first attempt we used his Pirus with a single wire earth return system.  Worked fine, however retrieving the wire from the brush and trees on the mountain was a pain.

He has posted many articles on this topic - check out the following links;

http://www.aprs.org/APRS-SPHEV.html

http://www.aprs.org/EV-charging-everywhere.html



Title: RE: Toyota Prius as an emergency power source
Post by: AA4PB on October 24, 2012, 07:37:02 AM
One advantage of using a Prius as an emergency power source is that presumably you drive the Prius on a regular basis so it gets properly maintained. An emergency generator usually only gets used during an emergency and most people don't take the time to regularly exercise and maintain them. As a result, when the emergency happens, the generator won't start or run properly because the carburetor is gummed up (even if you used fuel preservative).

and yes - this is the voice of experience....


Title: RE: Toyota Prius as an emergency power source
Post by: W8JX on October 24, 2012, 08:02:17 AM
One advantage of using a Prius as an emergency power source is that presumably you drive the Prius on a regular basis so it gets properly maintained. An emergency generator usually only gets used during an emergency and most people don't take the time to regularly exercise and maintain them. As a result, when the emergency happens, the generator won't start or run properly because the carburetor is gummed up (even if you used fuel preservative).

and yes - this is the voice of experience....


I never use fuel preservative but I do run carb dry with choke closed when done with them and store with either oil drained and a bottle of fresh oil or fresh oil in crankcase and cover them up. Never had a problem starting them even after sitting a few years.


Title: RE: Toyota Prius as an emergency power source
Post by: WN2C on October 27, 2012, 10:28:53 AM
Check out wb4apr or aprs.org.  Bob has on that web site a lot of links and I believe a link to how he uses his Prius for power on field day.  If you are an ARRL member, then look up the article he recently wrote on the same subject.  Hope this helps.

73 de wn2c  Rick


Title: RE: Toyota Prius as an emergency power source
Post by: N6OIL on May 25, 2015, 06:15:25 PM
Check this out. Who said you can't use your Prius as a home generator. http://shop.priuschat.com/converdant-toyota-prius-plug-out-generator-inverter/ (http://shop.priuschat.com/converdant-toyota-prius-plug-out-generator-inverter/)


Title: RE: Toyota Prius as an emergency power source
Post by: K5LXP on May 26, 2015, 06:22:39 AM

I think the common denominator is "emergency".  No matter what your power source whether it's a high efficiency genset or operating an inverter from the 12V system in your car, whatever gets you there counts.

Even operating portable I don't bother with a genset, I just run things off the car.  Yes, woefully inefficient.  But it works, is self contained and there's nothing extra to bring along and set up.  For the few times a year I do this, it's a no brainer.  Same goes for power outages.  In the decades I've lived here I can count the ones that lasted more than a few minutes on one hand.  What would be the point of buying and maintaining a genset I would never use?  Just to be ready for "when all else fails"?  That's not my goal, and I'll gladly cede the credit then to the whackers who are actually prepared for that.

So if someone owns a Prius and wants to use it as a standby power source, why not?  Just like having multiple radios and multiple antennas, an alternate power source is just another tool in the tool box.  I'd rather have that system worked out and available as an option and not use it, than scramble when other options don't work or are unavailable.


Mark K5LXP
Albuquerque, NM


Title: RE: Toyota Prius as an emergency power source
Post by: K6CPO on May 26, 2015, 01:06:41 PM
Just when I thought the last post decrying the cost of a good Honda inverter-type generator had expired, along comes somebody to suggest a Prius as a power source... :D :D :D

J/K, I couldn't ignore the ironic/silly comparison opportunity. Carry on...have a good day!

It's a good use for them.  They're a hazard on the road...


Title: RE: Toyota Prius as an emergency power source
Post by: W8JX on May 26, 2015, 04:00:22 PM

So if someone owns a Prius and wants to use it as a standby power source, why not? 


No real big advantage over just using your car with a inverter because the Prius has a very limited capacity in its 200 v NiMH battery, less than 1kw hr usable, and add power loss converting from 200 to 12v and engine will run a lot and not be very efficient. A Chevy Volt and Nissan Leaf have 16 to 25 times more capacity respectfully in their battery packs and Volt has a 55kw generator if you could find a inverter powered by 370 volts you would have a source capable of fully powering a few houses and its built in inverters are liquid cooled. A Tesla over 80 times more energy stored. Now that's a big backup house supply if you can harness it. 


Title: RE: Toyota Prius as an emergency power source
Post by: K5LXP on May 26, 2015, 08:35:54 PM
No real big advantage over just using your car with a inverter because the Prius has a very limited capacity in its 200 v NiMH battery

But the point is that it's 100% more than nothing.  If it's sitting in the driveway/out in the field otherwise doing nothing, efficiency be damned.  Lights are lights, power is power.

Quote
Now that's a big backup house supply if you can harness it. 

Harnessing it is the trick.  I've run stuff off my BEV pack but it's either been DC (lights, brushed motors) or through a 2-step conversion for AC:

(http://www.qsl.net/k5lxp/Static/IMG_5280.jpg)

Not optimum nor a lot of power but again, 100% more than nothing.  I ran 2A Field Day with it one year, powered the entire site.  But there's no point advantage to running battery unless you're QRP, and with a nominal 30kWh pack on tap, who wants to run QRP?

Mark K5LXP
Albuquerque, NM


Title: RE: Toyota Prius as an emergency power source
Post by: W8JX on May 27, 2015, 04:56:49 AM

But the point is that it's 100% more than nothing.  If it's sitting in the driveway/out in the field otherwise doing nothing, efficiency be damned.  Lights are lights, power is power.


And the same of which you can do with your car and a inverter in a pinch so Prius is no big gold mine here.


Title: RE: Toyota Prius as an emergency power source
Post by: SOFAR on May 27, 2015, 03:38:01 PM
It appears W8JX has developed a case of 'Prius Envy'.


Title: RE: Toyota Prius as an emergency power source
Post by: W8JX on May 29, 2015, 11:23:18 AM
It appears W8JX has developed a case of 'Prius Envy'.

No in the slightest. Drove all thee models and all too buzzy and handle poorly (PriusV does handle noticeably better than other two though and only model we even remotely considered purchasing) Volt is way quieter even in engine assist range extending mode and handles much better. Prius needs a serious overhaul/upgrade. Plus after 7500 dollar tax credit we got is was much cheaper than Prius too. We have no regrets a year later.


Title: RE: Toyota Prius as an emergency power source
Post by: KC2UGV on June 01, 2015, 04:17:20 AM
No real big advantage over just using your car with a inverter because the Prius has a very limited capacity in its 200 v NiMH battery

But the point is that it's 100% more than nothing.  If it's sitting in the driveway/out in the field otherwise doing nothing, efficiency be damned.  Lights are lights, power is power.

Quote
Now that's a big backup house supply if you can harness it. 

Harnessing it is the trick.  I've run stuff off my BEV pack but it's either been DC (lights, brushed motors) or through a 2-step conversion for AC:

(http://www.qsl.net/k5lxp/Static/IMG_5280.jpg)

Not optimum nor a lot of power but again, 100% more than nothing.  I ran 2A Field Day with it one year, powered the entire site.  But there's no point advantage to running battery unless you're QRP, and with a nominal 30kWh pack on tap, who wants to run QRP?

Mark K5LXP
Albuquerque, NM


I wouldn't even bother with the inverter to get DC --> AC...  Just stick a buck-boost DC-DC converter to get yourself a steady 13.8V, and start swapping out things you'll be running to operate at 13.8VDC.  Much more efficient, since your inverter is likely only about 60% efficient.  Buck boosts are in the neighborhood of 90% efficient as long as supply voltage is within +/-10%.


Title: RE: Toyota Prius as an emergency power source
Post by: W8JX on June 01, 2015, 05:23:02 AM
I wouldn't even bother with the inverter to get DC --> AC...  Just stick a buck-boost DC-DC converter to get yourself a steady 13.8V, and start swapping out things you'll be running to operate at 13.8VDC.  Much more efficient, since your inverter is likely only about 60% efficient.  Buck boosts are in the neighborhood of 90% efficient as long as supply voltage is within +/-10%.

If this was true electric cars would not be possible as efficiency would be poor.  Modern inverters are in 90%+ efficiency range. Electric cars are powered by AC motors driven by inverters powered by DC. Where most power is lost in powering ham gear from 120 ac is using linear power supplies which are not as efficient as switching supplies. If you do this then your over all efficiency (DC - AC inverter - Linear power supply) your over all efficiency will only be 50 to 60%


Title: RE: Toyota Prius as an emergency power source
Post by: K5LXP on June 01, 2015, 06:34:59 AM
Just stick a buck-boost DC-DC converter to get yourself a steady 13.8V, and start swapping out things you'll be running to operate at 13.8VDC.

Sure, if you can rationalize that expense vs a target run time.  Or do what I did and use what I already have, and not care that I can only run for 4 weeks instead of 6 when the goal is 2 days.  Perfection can sometimes be the enemy of good enough.

Mark K5LXP
Albuquerque, NM




Title: RE: Toyota Prius as an emergency power source
Post by: W8JX on June 05, 2015, 06:29:26 AM
Just stick a buck-boost DC-DC converter to get yourself a steady 13.8V, and start swapping out things you'll be running to operate at 13.8VDC.

I fail to see the reason for the fascination with this "got to have" 13.8v mentality. It is way over blown. Just like need for LMR400 for HF.


Title: RE: Toyota Prius as an emergency power source
Post by: AFA6MD on August 15, 2015, 09:54:48 PM
N4UM,

Don't worry about naysayers. I've used the Prius as a 12V operating station (nice to be sitting in a climatized car instead of sweating it out for hours and fighting insects; there is some RF hash when the motor comes on, but it's manageable, HF and large VHF antennas were mounted about 50ft away from car); and have also used it with a 1000W DC/AC  with long AC power cable running into house during a power outage (had no RF hash that time).

Keeping the gasoline nicely topped off, you have a fairly comfortable Comms vehicle :)

73