There are three reasons why the rechargeable flashlight cannot be charged:
Flashlight circuit break: internal wiring break, plug inside brass spring conductive sheet deformation, find the broken part is connected or spring sheet deformation shaping.
Charging circuit electronic components damaged: check step-down capacitor, rectifier diode. Replace damaged components.
Rechargeable battery failure: One is the lead-acid battery, the battery plate is easy to age. Clean the plate and replace the distilled water (or pure water, less effective). . Parts can be repaired. The other uses nickel-metal hydride batteries, or nickel-cadmium batteries. This kind of battery may not expire, but because of the memory effect and not charge, this situation is mostly caused by insufficient charge and discharge when used. At this time, the battery can be discharged, need to add discharge current limiting resistance, and then charge, and some can be repaired.
When this happens, the interior has been damaged, you can only replace the treatment, this situation is internal damage, poor contact, you can replace the maintenance treatment, to solve its stable use is no problem