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Hi John. Sounds like a good application for Li. Energy densities max out
around 95 WH per pound. Lead acid is up to 20 WH per pound.<br><br>
Li batteries are about 3.3 volts per cell, so the pack your client is
looking at may be 4 or 5 cells in series.<br><br>
It is probably important to buy a commercial pack, because most of these
batteries need their terminals welded into their series-parallel
connections -- not the sort of thing most wrenches are set up to
do.<br><br>
Also, most Li packs include battery management systems to keep them
equalized and properly charged and discharged.<br><br>
A123 Systems (
<a href="http://www.a123systems.com/#/applications/UPS/" eudora="autourl">
http://www.a123systems.com/#/applications/UPS/</a> ) has what they call
"drop-in replacements" for 12 V lead-acid UPS systems, so maybe
those packs are appropriate for solar charging. I recommend talking to
applications engineers at the Li battery companies.<br><br>
Aten Energy is also working on packs in 12 V nominal multiples.<br>
<a href="http://www.atenenergy.biz/Foxx%20Specs.htm" eudora="autourl">
http://www.atenenergy.biz/Foxx%20Specs.htm</a> . A 12 V 10 AH pack weighs
about 5 lbs. Their web site is lame and old, so you might have to find
some other way of contacting them.<br><br>
Here is an interesting product (11.4 AH) from the place where I buy my
NiMH household cells:<br>
<a href="http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=4089" eudora="autourl">
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=4089<br>
<br>
</a>Prepare your customer for sticker shock. <br><br>
John Veix wrote at 01:45 PM 8/24/2008:<br>
<br>
<blockquote type=cite class=cite cite=""><font size=2>Hi there,<br>
<br>
I have a customer with a hot air balloon doesn't want to use F.L.A. deep
cycle battery due to weight factors, but wants to use Li instead - and
also wants to use PV to charge it.<br>
<br>
I have never looked into this, but he seems to think the Li battery
charges at 16.8v. The battery will be small, probably about 10 a/h
and will be used for a transponder.<br>
<br>
Can anyone enlighten me about the feasibility of this application.<br>
<br>
cheers,
John Veix, N.Z.</font></blockquote></body>
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