Battery question

Andrea Daviero · Post by **Andrea Daviero** » Mon Apr 04, 2011 6:21 am

Lipo, life batteries has low discharge rate when stored. A fully charged battery may be laft on a shelf for an year or more. The rate is lower than other batteries on the market.

Allan Webster · Post by **Allan Webster** » Mon Apr 04, 2011 8:37 am

Please note the following safety bulletin from the British Model Flying Association:

http://www.bmfa.org/resources/lipobatteries.html

Please bear in mind that if you take risks with the batteries that you use then you are also imposing those risks on others.

Jan_Donadoni · Post by **Jan_Donadoni** » Mon Apr 04, 2011 9:54 am

Finally got my sets of LiFePo batteries.
2x 12,8v - 10ah for the 222
2x 12,8v - 22ah for the Jagd
2x 12,8v - 22ah for the Tiger

First impression, they are smaller but most of all MUCH LIGHTER than Pb batteries.
Second, without problems I can store even 4 of them inside the tanks, Even the Tiger, which would see 44 ah of endurance. For more complex situations the batteries could be easily divided into their components (the are actually composed of 4 x 3,2v blocks), it would be just a complex wiring job.
They could be safely and fully charged at 1C, that is in just 1 hour.
They need a LiPo saver circuit to prevent excessive discharge that could hurt the battery (just a few bucks). During real action they deliver much more effective / usable ampherage. That is, all tables usually show discharge over 20 hours cycle, but our models "run out of fuel" in 1 to 2 hours. That is the chemistry of Pb batteries will give just a fraction of nominal AH. LiFePo can withstand much better higher discharge current.

Just one clear specification. Li-Ion is different from LiPo, which is different from LiFePo. The LiFePo are probably the best suited batteries for our models (not fast racing models which run out of fuel in 10-15 minutes constantly at full power). They also have very good safety standards. They can be placed in any position since there is no liquid or gel part, so right upwards, on the side or even downwards is ok. And very important NO risk of acid leakeage.

Will post some pictures as soon as possible.

Andrea Daviero · Post by **Andrea Daviero** » Mon Apr 04, 2011 5:12 pm

There is a video on youtube about a life pack shorted (and one shoted by a gun), before it started to smoke it taken minutes.
No flames however.
Obviously a shorted battery, also if it is a pb battery, is not a safe thing to do.
LiFe (also called LiFePo4) are more safe than lipo as they are not exposed to the risk of fire.
I have the only trouble on my model to make a new balancer plug to charge the batteries together and the problem to find a battery low voltage cut off able to cut off the circuit.