School me on batteries

[Jon K]

Hey guys I have a Mini Rio and now 3 stock batteries which I cycle for fun at the lake. Its great, but I'd like to find more about batteries.

I see everyone mention Lithium Polymer batteries - is there anything keeping me from running on on my boat? I think the stock battery is 7.4v and I see 7.4 LiPo batteries out there. Any links to appropriate batteries for a Mini Rio? Does the battery pack offer anything over my NiMH packs? Do I need a special charger?

Thanks!

[ED66677]

Not sure it fits on this boat and especially with the ESC you have in it but...
Lipo's are... hummmm... better! for the same capacity they weight half of the same in Nimh, so if you double the actual capacity you'll stay at the same weigh and double the run time, the discharge rate is also higher.
You'll need a charger that is Lipo compatible and a balancer (or a charger/balancer in one) balancing Lipo's is very important as they are much more sensitive to charge/discharge voltage, you don't want to exceed 4.2V per cell and you don't want to go below 3.2V, so during charging process you want to be sure that one cell is not higher/lower than the other of 0.1V, the balancer does that. If you don't have a balancer your charger may stop charging once the pack has reach its limit but you may have one cell at 4.3V and the other at 4.1V, the first one will then not last long and the other one is not fully charged!!!
During discharge, the ESC has to be able to reduce/stop the power when pack voltage reach a bottom limit (6.4V for a 2S pack) so it has to be Lipo compatible, if it is not, you may want to use a aditional BEC/Lipo Saver that goes between the receiver and the ESC, this device will reduce, and after few seconds, cut the signal from the receiver to the ESC, I know there's one on the market that is programmable so that you can set the voltage cutt-off but sorry I can't remember the name!