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Best battery chemistry for high ambient temps?

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Posted by Charlie on August 27, 2006, 9:54 pm
I'm specifying components for PV installations in equatorial Africa
where temperatures can routinely approach 100 F.

I have seen operating ratings for AGM batteries at 140 F Tmax, but am
having a hard time finding Tmax for both Gel and flooded cell deep cycle

I'll take the obvious steps to minimize temperature, but I'm still
concerned about thermal runaway and shortening the life of the battery

Can anybody point me to an unbiased resource that I can use in design?

Thanks in advance!


Posted by Charles Foot on August 27, 2006, 11:21 pm
Charlie wrote:

Nickel Iron (NIFE) cells *may* be the solution. Here's a link to a
flyer: http://www.beutilityfree.com/batteryNiFe/battery_flyer.pdf
Perhaps somebody in the group has more information on this type of cell?

Posted by Charlie on August 28, 2006, 12:17 am
 Thanks for that link - it's VERY interesting stuff!

Very high initial costs, with astronomical claims of cells still
delivering full rated power at *50* years old.

I don't know whether commercially available charge controllers know how
to deal with them though.

I'll investigate further, though I think in the African market, the high
initial cost might rule them out.


Charles Foot wrote:

Posted by Windsun on August 28, 2006, 2:20 am
 One of the huge problems with NIFE batteries is their very poor
efficiiency - you can lose 50-60% of your power just charging them. Much of
what they say is true, but the size, weight per amp-hour, and grossly
inneficient charge/discharge cycles make them pretty unpopular.

And for the record, Gelled batteries are NOT good in hot climates.

Free Solar Discussion Forum: http://www.wind-sun.com/smf/index.php

Posted by danny burstein on August 28, 2006, 3:04 am

In the Bad Old Days they were used as power levelers in
streetcar runs. They'd be hooked up in a shed along
the track and get charged up between car runs.

While they weren't, as you've mentione, the most
efficient, they were very low maintenace and
lasted just about forever, even in the middle of
nowhere with no one checking on them.

When the train came by, they'd partially discharge
and supply part of the power. Made it
much more practical than providing a grid arrangement
for full maximum power for the whole track run..

(since these were stationary and used by railroads,
the weight and size was secondary compared to the
long term reliability).

They've also been used in remote arctic weather
stations such as Drift Station Zebra - again, for
the very low maintenance and high reliability.

Knowledge may be power, but communications is the key
[to foil spammers, my address has been double rot-13 encoded]

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