Constant trickle charge methods for extended periods heat the battery and produce memory and dendrite crystal formations. Fast charge methods that end when overcharge is detected also heat the battery and produce memory and dendrites. Unusable Batteries NiCd and NiMH batteries with memory can actually have a near full-charge that electronic products cannot use. Memory causes a sudden voltage drop in the battery voltage. This sudden voltage drop occurs within a few minutes of power-up, and the product stops after what appears to be a complete recharge.
Dendrites form leakage paths that quickly drain a battery after a recharge.
In both cases the battery can be classified as damaged, but technically it is unusable. It is also very time consuming, and with further charging, the memory and dendrites will return. The AdvanceTec Burp charging method prevents their formation. Battery Failures Unsophisticated overcharge methods allow the battery to get hot before the charge is ended. Heat caused by overcharging greatly accelerates the aging process in batteries.