The problem is that I have a Raycool 1000W Carbon Blue electric scooter that started to fail. I checked the battery first. The battery is composed by three 12v 12ah lead acid batteries. (the one in the picture)

I checked the voltage and the 3 in series had 40V. First question: Are they overcharged?

Then I checked the charger voltage. It gives 48V. Is this normal if it's a 36V charger? Also the end of the charger is a xlr 3-pin. One of them is totally disconnected, is this normal?

I would like to know if I have to replace the batteries or the charger. Thanks and sorry for my bad explanation.

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1 Answer 1


All sounds normal, presuming the charger is poorly regulated and you measured it without a load.

1) See the voltages on the battery label! 40V/3 is within that range.
2) The charger can provide up to 45V (15V x3 - see that label again) under load. It may well be 48V when unloaded, check it again while charging.
3) Only 2 pins needed, so sounds normal.

So, test the batteries.

Take a lab power supply, set it to 14.4V and current limit to 3.6A (or less) according to the battery label. (Or use a 12V battery charger if you have one). Charge each battery individually from that until the current falls to 0.5 or 0.25A or some such figure.

Then connect a 12V lamp (or some other load) across each battery and see how long it lasts : if the load takes 2A, double the time to get the capacity in amp hours. Replace any battery which died much below 12Ah. If they are all a bit low, replace the lot - anything else is false economy.

  • \$\begingroup\$ Thanks for answering me! I will test the batteries. I have another question. The original charger was this one Is there any problem using the actual one instead of the original? The only diference I can see is the output. \$\endgroup\$
    – Pol
    Oct 7, 2017 at 13:24
  • \$\begingroup\$ I was presuming the charger was the original, matched to the batteries by the supplier. It's certainly possible if the on-load voltages and currents are different, for the replacement to kill the batteries sooner than the original. But if they both fulfil the battery specs, itshould be OK. \$\endgroup\$
    – user16324
    Oct 7, 2017 at 15:12

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