(05-23-2016, 03:14 AM)lee Wrote: But Li-ion is completely different from Li-po. I think Li-ion is much more safer and is using by cell phone. the only problem for Li-ion battery is that it will be aging even you don't use it but it has no memories effect. but yes, running too low it will hurt the batteries life and unsafe to recharge.
Li-po is a subset of Li-ion. There are also Lifepo4 which are the 3.2 volt variants and are safer than li-po 3.7 volts. The main issue with using these in trains would be the need for a voltage alarm as mentioned by Tramp. Ucwepn mentioned an expensive bakance charger was required but this should not be required for single cells as balancing is required across multiple cells for Li-ion.