I have a home-made battery pack, and am wondering if it is safe to charge.
Background - I won a cheap chinese bike light and 4x18650 battery pack. The battery pack was particularly nasty - I suspect it was 90% air. I have since lost the battery pack when it fell off my bike.
It came with a US wall charger labelled as
Li-ion Charger Input: 100-240V~ 50/60Hz 0.35A Output: 8.4V =-=-= 1000 mAh
(that symbol is supposed to be a horizontal bar with three dashes below it.)
I have used two CR123A 3.6V batteries in series, and this runs the light part nicely. They are "protected" ones, confirmed by the slightly longer length and the small vent holes around the positive terminal. These were clipped into a battery holder, wires were soldered to tabs, and the whole thing was covered in heatshrink for water protection.
Questions The battery pack is literally batteries and wire. Should there be anything else inside the battery pack, or does the "protected" part of the battery cover that?
Is this charger suitable to charge this battery pack?
I guess it will take 90-120 minutes to charge - is that reasonable based on 1000 mAh and 880 mAh capacity of each battery?
Edit - since asking, I connected the new pack to the charger and left it for 3 hours. The charger's LED started as red, and then went green after about 150 mins, suggesting it sensed the chargedness of the pack and dropped to a lower power state.