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Li-ion battery charger Answered

i have taken apart a cheap disposable phone. i got a better phone because this one died. the charger still works though. i have 3 nokia 3.7v battery's. all the same. could i use this to charge the battery's in parallel.



8 years ago

 I've done the same thing, though I've found, in my case, the batteries must be at the same level of charge in order to get it to work right. Otherwise, the charge seems to apply a charge to all of them based on the battery with the highest charge.

This is because, when you apply batteries in parallel, their voltages are not stacked on top of one another, as they would be in series. If you were to hook them up parallel, then use a volt meter to test them, you would only be getting that of the battery with the most charge.

So, when one battery is charged, (mine has an auto-shutoff, i don't know if yours does) the remaining batteries stayed at their semi-charged levels and stayed that way until I reorganized the battery pack.

Furthermore, it is, i found, not recommended unless the batteries will always be at the same level of charge when beginning the recharging cycle, as most chargers will apply a voltage slightly higher than that of the current charge (ex: the battery is at 2.5v, so the charger keeps pace above it by .1 volt, or something similar)

when one battery is above the others, all but that one is being charged improperly

summary: yes, it will work, but I only recommend it if you are either using the batteries for the same task at the same time, or are willing to only use the charger in parallel once you've checked that both batteries are at the same level