[Tinkerphones] New tinkerphone gadgets in Goldelico shop?

Pičugins Arsenijs crimier at yandex.ru
Tue Nov 14 19:10:12 CET 2017


> But are they safe for those batteries ? Did you try them?

I have disassembled some of the "universal springy pins" chargers and they do not seem safe, they don't seem to use specialised charging ICs and usually use some kind of half-assed passives-based solution that ignores the CC/CV cycle requirements for LiIon charging. They could be safe to use if you were to throw out all the electronics and replace them with your own.

> I half remember most smartphone batteries include a charger chip
> and GTA04 batteries do not (the chip is in the phone and should be
> in the charger).

That is definitely not the case. 99.999% is that the "charger", that is, the thing with a MicroUSB cable you plug into the wall socket, only provides constant voltage and some guarantee about max current available (say, 5V/2A). The phone has a charging chip inside, which takes 5V and uses it to charge the battery, controlling the charging rate and stopping the charging process when the battery is full. The battery itself doesn't have any provisions for charging inside, aside from a protection circuit that prevents it from overcharging (doesn't have to be there, but is included in 99.999999% phones with LiIon batteries), and a thermistor so that the charger can measure temperature of the battery and stop charging when the battery is too hot. Talking about protection circuit, it protects from 1) discharging the battery too deep (because it will get damaged, and in certain circumstances might burst into flames when charged the next time), 2) overcharging the battery (even though the charger is not supposed to do that, there's still a small chance, like charger short-circuiting 5V onto its output because of a power surge) and 3) short-circuiting the battery. Again, that is just how phones are built, at least for a decade now.

-Arsenijs


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