Electrically Powered Ultralight Aircraft

Please keep in mind that there are many lithium ion and lithium polymer
chemstries. It isn't too informative to just say "Lithium Polymer" or
Lithium Ion" without stating the precise chemistry. Further, chemistries
are changing almost daily. Many are proprietary. There's no such thing as
a "standard" lithium battery chemistry.

Valence, Saft and A123 Systems use chemistries that are far safer than the
relatively inexpensive Korean made model airplane batteries - safer than the
typical laptop or cell phone battery which are spec'd mainly on price.

Interestingly, the safest chemistries in the latest cells also offer faster
charging, greater energy density and will endure a FAR greater number of
charge cycles. They're also potentially cheaper.

I've already made a cell holder for A123 Systems "A1" cells. That's the
lithium phosphate nano cathode one used in 36V DeWalt power tools. You can
buy a couple of new DeWalt 36V power packs for $50 or so on Ebay. Then,
dismantle the pack to retrieve the individual cells. My pack will be 13.8
volts and 11AH weighing 3 pounds. It will be the same size as a 7AH 12V SLA
but weigh less than half as much.

Bill Daniels

Some Lithium cells can suffer thermal runaway and fire. Others are
extremely
wrote in message
oups.com...
On Aug 10, 5:12 pm, Dave wrote:
Are

you able to provide links to any forums or web sites related to this

Check this out:http://www.calcars.org/news-archive.html

David Johnson

Lithium Polymer batteries are widely used in RC planes, cars, etc and
are known to be potentially dangerous. Most runaway fires occur during
charging but it has also occurred to a lessor degree during discharge
and even storage. Vented charging safety bags are recommended for this
reason. There is a video on this link that shows the explosive power
of small LiPo's. Consider the size differance of these batteries to
the one hung under the trike in one of the first posts or those that
could be installed in the wings of a sailplane.
http://www.liposack.com/video.html

On Aug 11, 9:47 pm, "Bill Daniels" bildan@comcast-dot-net wrote:
...
I've already made a cell holder for A123 Systems "A1" cells. That's the
lithium phosphate nano cathode one used in 36V DeWalt power tools. You can
buy a couple of new DeWalt 36V power packs for $50 or so on Ebay. Then,
dismantle the pack to retrieve the individual cells. My pack will be 13.8
volts and 11AH weighing 3 pounds. It will be the same size as a 7AH 12V SLA
but weigh less than half as much.

Don't forget to add a brick of lead to the bottom of your
new battery pack, to keep the CG in the right place ;-)
Best Regards, Dave "YO"