E-bike Battery Question...

Discussion in 'General Electronics Chat' started by 4rbd, Jul 7, 2015.

  1. 4rbd

    Thread Starter New Member

    Jul 7, 2015

    I'm building an e-bike from a kit and I have one question to ask before I attempt to charge the battery. I had to buy the battery separate so I'm not sure if the charger that came with the kit is compatible. The battery says 36 volt 12ah but the charger label reads 36volt 17-20ah. Is it ok to use this charger or will the extra "ah" fry one of these?

    Many thanks for any insight.
  2. MrChips


    Oct 2, 2009
    1) Chargers are not rated with Ah specifications. Something is wrong with that charger label.

    2) What type of battery is it? Sealed lead acid battery (SLAB) or lithium-ion? The charger must be designed to suit the battery chemistry.

    You will need about 44V @ 2A for SLAB,

    42V @ 2A for Li-ion.

    You could measure the no-load voltage of the charger and also the voltage when connected to the battery.

    3) For your first time charging, do not charge the battery unattended. Monitor the temperature of the battery. It could get warm but should never get hot to touch. In any case, the charger must shut down when the battery is fully charged. If the charger does not shut down automatically after 8 hours of charging something is not right.

    4) Make and model numbers or pictures of your battery and battery charger would help us to better help you.
  3. crutschow


    Mar 14, 2008
    Perhaps the charger manufacturer rates the charger based on the typical charge rate for the battery type (like 10% of the AH capacity).