12v Transformer question

[joules99]

My son has a radio controlled car and has lost the transformer to charge it, can someone tell if the transformer should match the voltage of the batteries inside (ie there are 8xAA batteries - therefore 8x1.5v=12v) is this right or to rercharge batteries do they need more voltage, probably really stupid question??

[MargeB]

Same voltage as the batteries. They are very readily available.

(ps. You definitely don't want to overvoltage).

[Buenchico]

Er, sorry to complicate matters but there can't be a definite answer to this question. If the circuitry inside the car has the all the batteries in series with the charging voltage applied at either end then 12V may well be appropriate. If, however, the circuitry is arranged so that, when charging, the batteries receive charge as 2 banks of 4, then it's possible that only 6V is required!

If it's possible to remove the AA cells, the easiest way to get round the uncertainties is to buy 2 cheap chargers, of the type that charge 4xAA each.

Chris

[Space]

If the batteries are rechargeable,
their voltage is 1.2V , not 1.5V .
Anyway, that doesn't say what voltage they require to be recharged ... So I would buy a battery charger !