This is a modification for vintage SONY BP100/200 batteries which are used by D555, D15, D25, D10, Fisher PCD1, KENWOOD DPC7 and etc. The original batteries inside of the BP100 are lead acid batteries which seldom survive after 20+ years.
Now we can get rid of the broken cells in the BP100/200 and install two 4.2V 2700MAH Li-ion cells. Also a smart charging and protection circuit will be added along with the cells.
The smart charging circuit will charge the cells by three stages: 1: Precharge the cells if the cells' voltage is lower than threshold; for example, if the battery base hasn't been used over two years,so the voltage drops a lot. 2: Constant current charging period will charge most of the battery capacity but the current won't be too huge to warm the cells. 3: Voltage regulation period, the cells' voltage will be monitored no more than 4.2V, also the circuit charges the cells by a tiny current to compensate the capacity.
When charging the battery base, a tiny LED on the front panel will be red, it turns green after the charging is finished. The charging will last about 6 hrs. The battery base can power CD players around 10 hrs. Obviously, battery drove CD players will have more precise and clear sounding experience.
Also,the CD player is needed to be modified to fit the new cells.
The service is suitable for both BP100 and BP200 batteries.
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