Posted by: booey
Battery - 08/10/2003 11:55
Should the battery be drained completely before recharging?
I dont wanna shorten battery life if thats the case..
b
I dont wanna shorten battery life if thats the case..
b
when you don't plan to use it for a while, discharge it to around 40%It is true that the optimal STORAGE charge level for Li-Ion is about 40% of full charge, but in practice this is hard to do.
aren't all recharchables stated as having a battery life of..... "x recharge cycles"?Rechargeable batteries ARE marketed that way, but the reality (as usual) is more complex.
Devices that use a multi-cell NiCD or NiMH battery pack often will operate until some minimum voltage output from the battery pack is no longer available (and the device turns itself off). If that minimum voltage happens to allow ANY of the cells within the pack (especially if those cells are not perfectly matched in capacity/voltage characteristics) to drop below the minimum allowed voltage per cell, then that cell is internally stressed and is aged more rapidly than the others in the pack
the voltage drop of the weakest cell may be masked by the steadily increasing voltage of the other cellsI believe that many/most Li-Ion "smart" charging systems (and presumably the type incorporated in Karma) actually monitor the voltage of each cell in the pack. This allows the charger to be sure of not violating the fragile charge/discharge requirements of the Li-Ion battery type.
packs have been constructed out of cells with very closely matched capacitiesOn that note, the fewer cells connected in series (ie: the lower the overall voltage of the pack), the less troublesome cell mismatching is.
I don't know about current RC practices, but from a battery lifespan perspective, the best arrangement would be very few cells in series
Do any RC systems use a smart power management system in the vehicle?
Do any of them regulate (voltage boost) power output, such that MORE power can be delivered to the motor near the end of the race, despite the rising internal resistance of the batteries?
For everyday use, should i drain my Karma all the way before recharging or not?If your regular/daily use pattern would normally result in rather small discharges (as a percentage of available battery capacity), then I would suggest going for a few days until the battery is mostly (more than half) way discharged, then fully recharging.