Just a quick one for all you bright modellers out there.
I have two 7.2 volt batteries wired in series to produce 14.4 volts. One is 1600 milliamp hours and the other is 3000 milliamp hours.
I left them feeding a speed controller overnight by forgetting to switch it off. The next day, the speed controller light had gone orf, showing that the supply had dried up.
Upon testing it was found that the 1600 was dead flat and cannot be recharged.
. The 3000 was able to be recharged.
My question is what happened internally to these batteries during the discharging process ?. Did the one battery have any bearing on the (alarmingly) flat battery by treating it as a dead short and continuing to feed a reduced voltage to the speed controller ? or did an open circuit occur and stop the process of current drain. ?
I shall, of course, always fit matching batteries in future, but it was an expensive mistake to make, me-thinks.
As a PS, can the flat battery be re started with a direct feed of (say) a 6 volt source from a lead acid type, as it will not charge using the sophisticated charging unit I have.
Over to you.
Ken