iceman wrote:Lithium batteries are not %100 reliable - they also die especially if they are over charged or for some reason drop below minumum voltage by too far a margin. Applies to all Lithium even in small devices. For the price, as mentioned it does not seem worth it as a good normal PCX battery will last ages.
I looked into Lithium batteries - helps to have two electrical engineer brothers. I was interested because of the battery in my 400 burgman was near horizontal & they're notorious for going through batteries (it's only an issue if you let it get too low - but that's another story). The PCX battery is at a bad angle too. Mine came with a Lithium battery that the previous owner fitted. They can be used at any angle. I can shed a little light on your concerns. Li batters like being stored with 70-90% charge but dropping them to zero won't kill them. After being away from my PCX for a month I returned home to find battery voltage down to 1.6V. An hour on the charger did nothing, but it turns out the issue was my charger. It couldn't 'see' a battery so didn't charge. On advice from my brother I reconnected the charger then touched 12V from a car battery across the terminals for a second. I heard the battery charger click & commencing charging. An hour later the battery was fine. That was a couple of months ago & it's still working without issue.
re: overcharging, Li batteries will burn explosively if overcharged, just ask Samsung - however in a Li battery box, there's some clever circuitry between the terminals and the actually Li storage device to control charging rates.
In short: If your battery is so flat you need to use an external charger on your PCX battery, remove it first. If it's lead acid, it should be upright to charge. If it's lithium, given you're relying on some computer controlled circuitry to stop it exploding, and given its proximity to the fuel tank - best play safe. Rumor has it that a samsung laptop battery blew a commercial aircraft out of the sky.