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Registered Member #3781
Joined: Sat Mar 26 2011, 02:25AM
Location:
Posts: 701
it would just be easier if you buy/sourced a 9v charger that is meant to charge batteries for RC cars and stuff, then you could just leave it plugged in without having to watch it
Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061
Bad move, Li-Ion cells need CVCL (Constant Voltage Current Limit) charging.
Depending on cell type you first charge it with a constant current of 0.3C up to 4V then constant *voltage* at 4.15V +/- 0.05V until current drops to 10% of cell capacity i.e. 100mA for a 1Ah cell.
DO NOT CHARGE IT beyond that point, or it will become dangerously unstable and possibly vent with flame. This is especially true with Li-Po cells and the temperature rise yielding a VWF can be less than 30C above room temperature which means the cell can feel only warm to the touch before runaway begins.
I have charged these manually before but it is essential to do it right. The safest method I have found is to simply use a spare Li-Ion camera charger as this has the existing failsafes etc and shuts down when charged. Got me out of a few sticky situations with phone cells before.
Wonder why they don't make a "smart" Li charger which just reads the markings off the back of a cell with a webcam, OCRs it then uses this for calculating required charge.
Can't be that hard methinks, and have it default to "dumb" charging if it can't read the values or they are inconsistent with the cell being examined.
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How can I charge this?
