Answer to "Battery replacement? (Soldering, series of questions, detailed)"Hi! I bought this Battery: “ MODEL 582535 SP5 3.7V 600mAh Rechargeable Battery For tachograph papago F300 “ It did not work (no charge process). Then, I used the small PCB from the old (orginal Marshall) battery and soldered it with the new battery, replacing the pcb that came with it. Now, everything works fine - yeah !! No guarantee though that this procedure is safe and works for you, too! Good luck and have fun! Volker
Answer to "replacement battery for Marshall’s MID Bluetooth headphones?"The original battery contains a small PCB; maybe some charge control electronics. I tried to replace it with a battery with three wires and similar capacity from China. No success yet. I will try now to use this battery with the pcb from the original battery..