Am,I right in thinking if you get the polarity wrong on a charger you can blow the circuit board of the device you're trying to charge?
Reason being, I have an old FLiR i7 thermal camera that the boy and I were going to use on a game day, so we did a battery test. Happy to discover that despite it'd age, there was a good 5 hours battery life.
I then had to lend it to a customer (long story) who tried to charge it using an adapter he had at home that was the same voltage but it turns out unknown polarity).
When I got it back there was about 5 minutes battery life left, and when I plugged it in with my charger it wouldn't take any juice.
So I know the battery was/is good, so he's either fried something on the camera or my charger has spontaneously shat itself (my multimeter is too chunky to get inside the plug to measure the angry pixies). Possibly a blown diode?
Tah in advance!