Prius as UPS [RE-wrenches]

[Todd Cory, Mt. Shasta Energy Services]

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 From below:

>One more point: Since the Prius cells are only rated for 6.5 amp hours, 100%
>discharge would provide less than two kilowatt-hours of stored energy before the
>hybrid engine would need to crank up.
>
To get the Prius battery to last for the 150,000 mile warranty, the 
small onboard battery is cycled between 80% max charge and 50% max 
discharge. This leaves little room for any offboard use, let alone 
vehicle propulsion. 

30% of 2 kWh = .6 kWh.

If I have one gripe about our Prius, it is that the battery is far too 
small. IMO trying to use this as a UPS is not at all practical, and 
would likely damage the battery/void the warranty. Maybe for the 2010 
gen 3 plug in Prius, but definately not gen 2 or gen 1.

Todd


Dick Ratico wrote:

>Carl,
>
>I'm intrigued by the idea of using the Prius as a substitute for the usual
>fossil fueled generator in a battery backup system. Here in VT / NH, where it is
>not uncommon to go two weeks without much solar support, a generator, a backup
>to the backup, becomes necessary.
>
>The best fit for the Prius, might be as a means to eliminate that redundancy,
>and to minimize the size of the Sunny Island's required 48V battery, especially,
>as in your client's case, one supported by a 5kW array. The Prius would be used
>more as a charging source, as it seems to be on the "priUPS" website, a very
>interesting one by the way, mediated by an appropriate Sunny Boy inverter, which
>is already designed to work with the Sunny Island. Perhaps the same Sunny Boy,
>Boys, (Girls?) already in the system could be used, through a transfer switch
>setup. It would certainly be a feather in SMA's cap to be able to offer this
>option. It would also add momentum to the overall plug-in hybrid technology.
>
>In this installation the DC voltage window in the SB5000 may or may not not
>match the Prius' battery voltage. It has also been pointed out, that there are
>likely other complicating factors as well, including the existing Sunny Boy
>software. 
>
>It seems to me the NEC does not address the situation of the high voltage Prius
>battery (parked outside a residence) being connected to a grid-tied inverter,
>also outside.
>
>Dick Ratico
>Solarwind Electric
>
>
>Mick Abraham wrote:
>
>"Carl Adams wrote:
>
>"The customer is intrigued by the idea of using his Prius as the
>battery bank. (for a Sunny Island under consideration).
>
>Mick says: Amory Lovins' Rocky Mountain Institute had speculated about using the
>"supercar of the future" in a manner similar to Carl's description. It's a keen
>idea, but...
>
>heres a link for info on the Prius batteries of various model years:
>
>http://www.eaa-phev.org/wiki/Toyota_Prius_Battery_Specs
>
>Note the high voltage/low ampacity characteristics, and remember that Sunny
>Island is designed for a 48 volt (nominal) battery. The Prius uses hundreds of
>"flashlight sized" batteries all wired in series. One should not (even
>temporarily) connect these cells into parallel strings at lower voltage, because
>ni-mh is widely known to be unsuitable for charging strings of cells connected
>in parallel.
>
>The person behind the "priUPS" website that Carl referenced got hold of an
>"unterruptible power supply" designed for high voltage batteries in order to get
>an inverter for high voltage DC input. Here's a link:
>
>http://www.priups.com/misc/update-2005-06-1.htm
>
>A high voltage UPS seems more appropriate for the Prius battery string than a
>Sunny Island, except for the code problem of a high voltage battery connected to
>a building, and except for the problem of trying to properly charge costly ni-mh
>cells using a UPS that was actually intended for lead acid...
>
>One more point: Since the Prius cells are only rated for 6.5 amp hours, 100%
>discharge would provide less than two kilowatt-hours of stored energy before the
>hybrid engine would need to crank up.
>
>
>
>Mick Abraham, Proprietor
>www.abrahamsolar.com"
>  
>


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