dlj04(at)josephson.com
Guest
|
 Posted: Wed Feb 06, 2013 1:51 pm Post subject: Lithium battery comparisons |
 |
|
I was puzzled by the new term "PbEq" in rating capacity of lithium
secondary batteries used in aircraft, motorcycles, etc and tried to find
out what they were really talking about. I couldn't find anything on the
websites for Aerovoltz or Full Spectrum (the two brands sold by Aircraft
Spruce) and was puzzled by the claim of 20 AH for a 2.5 pound 12 volt
battery.
It turns out that "lead equivalent" amp-hour capacity is actually three
times the actual cell capacity.
http://www.batterystuff.com/kb/frequently-asked-questions/powersports-batteries-faq/lithium-iron-faq.html
This would explain why these new wonder batteries, although great in
some respects, don't last quite as long as we'd expect them to!
We know that you don't discharge a lead-acid cell more than about 1/3 or
it will suffer loss of capacity. Sometimes, as in the case of losing an
alternator at night or IFR, we're happy to kill a battery if it gives us
power for long enough to land safely. Some LiPo and LiFe batteries can
be discharged to 80-90% without damage, but this doesn't help us if we
are expecting 20 AH and the battery is actually made of 6 AH cells. If
you want to know how long they will run your radios while you're up in
the air, you need to know the actual cell capacity and discharge curve
to figure out how many minutes you have before the voltage drops to the
point that's unusable by your equipment.
--
David Josephson
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
