I've been using a LiPo battery for my FT-817. No problems recharging it with it's own charger, no heat above the ambient temperature. I take some precautions like not letting it discharge too low and using a flame proof container when charging but as I said no problems.
Sent from my iPod Amir K9CHP
On Jun 24, 2010, at 10:51, Gregg Wonderly w5ggw@cox.net wrote:
The most predominate problem is people using the wrong chargers for them. They think to themselves, "This is a rechargable battery, I can just use my expensive NiMh/NiCd charger I already bought". The problem is, of course, that the LiPo cells have a completely different charging profile that is short-high and then long-low, instead of the previous long-high, short-low of the other common cell types. Thus, people end up charging them for too long at High-C and boom, they overheat and catch fire.
The Radio Controlled Model industry has already gone through large failure occurrences with the charging problem, burning up multi-hundred dollar/hour investments, catching houses on fire etc.
Most people now charge LiPo batteries outside the models, and use a fired-clay pot or other heat tolerant container just to be safe.
Using the correct charger goes a long ways towards nearly eliminating all problems. You have to have a temperature monitor to really do it right, but any production battery charging facility needs that.
Gregg Wonderly
whiteld@usa.net wrote:
Following up on the Lithium polymer battery mention I Googled them and was disturbed to find:
-high fire risk. One seller offers flame retardant bags to put the cells in while charging them... for $25
-(as warned) high prices especially considering the more-unique balanced charger / discharger devices at ~$100 and up being required in addition to the cells themselves
-a hazardous materials uplift for FedEx shipment ranging from $25-$45 depending on destination, on top of normal shipping rates
All of that tells me they're "not ready for prime time" though the current capacity vs weight looks very promising.
I will wait and watch, hoping the technology matures into something safer and less costly as time goes on. Likely it will, particularly the cheaper part, though it appears some safety issues have to be addressed meaningfully.
Thanks for the mention. It is interesting.
Lowell K9LDW
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