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Lifetime Battery

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I want to know if the charging circuit here is successful

From a quick view, it doesn't look like there's any
charging current limitation (unless the BMS has some).
And that battery won't last forever either.
It might help if you draw the schematics.

Kind-of spam'ish, might be a bot. I've placed the OP on the watch list. If nothing else, moved to Dodgy Technology.

Indeed, no current or voltage limit, this is definitely dodgy. He is using the protection circuit from a dead battery, so there is at least overvoltage protection, but this is not a charge circuit. The protection circuit is just supposed to be an extra protection in case of a failure of the charger voltage limiter. If the protection circuit itself ever fails (*) the polymer battery will directly receive 5V (minus the 0.6V from the diode) and will probably ignite.

USB chargers usually don't limit the current either and some can provide 2 amps or more. A 200mAh polymer battery won't survive long with such a treatment, but at least with such a high current the overvoltage protection will kick in pretty quickly.

Besides, how is this useful anyway? I don't remember the last time I had to change any battery in a remote but it has been years.

(*) the probability of the protection circuit failing is also higher in this case if charging with a higher current than designed for. They are usually protected against high current in the discharge path, but not in the charging path. Sending several amps through a small mosfet could destroy it and make it fail as a short, and then there would be no protection at all.

Just use a bunch of regular low self discharge Eneloops or the like. They will last for a long time, are easily exchanged/recharged and certainly won't explode.

Just say no to stupid ideas.


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