Thank you for your help. I really appreciate it.
But something is still weird. The device should be able to run from the 5V/2A input,
Theoretically yes, However my unit came completely flat I mean ZERO charge.
It would not start untill the battery level got to about 10%
It would turn on, say JXD, then turn off.. this is while it was on charge.
I guess. I unsoldered the battery and connected a power supply to the barrel plug. The power line that normally goes to the battery (and is now disconnected) gives me a voltage of 2.4V. I expected it to be almost 4V. Something seems to be wrong here.
Not sure whats going on here, it might be nothing.
the controller on the battery most likely does not actually do teh charging, just protects the battery from various conditions such as:
over charge (cut off)
over discharge (cut off before battery enters a state where it's technically unsafe to charge again)
reverse polarity (if you tried to charge it with the terminals reversed)
short / fault protection (if you simply shorted the terminals together)
temperature (cut's off access to the battery if it exceeds a given temperature)
It's doubtful teh circuit board on it actually provides any logic to charge the battery it just keeps the battery safe from various conditions.
IF that's the case then 2.4v out of the terminals on the PCB of the device might not be usual since it can't detect a battery. you would not see higher voltages out of it unless it was trying to charge the battery.. but since the charge circuit needs to be aware of teh batteries current level it would not just blast out power.. Li-po/ion's do not charge at a constant rate, at low levels and about the final 10% the battery is charged at a lower rate.. so the chargers for li-po/ion batteries can't be "stupid"
The battery itself, now that I had it removed, still gave me 2.76V, directly from the battery AND through the circuit. So that 0V reading I had yesterday is a mystery to me. May have been a short, as the battery's PCB is poorly isolated.
I connected the battery again, removed the external power supply and measured 2.76V on the + and - points on the main PCB. Of course, that's what I expected.
So there seem to be two problems. The battery voltage is too low and the external power is "eaten up" somewhere on the way, so it can't recharge the battery. Some blown up capacitor maybe?
ya sounds like you might have a problem with that pack if it's now reading voltage from the batteries protection circuit then it sounds like it has not tripped into over discharge (assuming it protects that by cutting the battery off which most do since that's a basic level of protection.
If you have a hobby charger try charging it, let it go thru the protection PCB since you're getting a reading off it now.. it wont interfere with the hobby charger.
If it takes a charge then solder it back up and see how it runs, if it does'nt then i'd replace the battery back (and protection pcb)
if you don't have a hobby charger but have a spare li-po running around (capacity is'nt important but i'd want one with at least 1000mah)
You could wire it to the battery terminals in teh device and see if it can charge it up.
This is of course assuming the PCB on the battery is only for protection and is not the charging circuit (which it usually is'nt)
you could also try wiring the pack back up and see if the voltage goes above 2.4.. the voltage should be higher then teh battery pack if it's charging.
