My car is not being used on regular basis, sometimes not for weeks/months. Can I use one of those AA 12V Solar panel 2.4 watt car battery charger to keep the car battery topped up all the time. Can I connect this through either the cigarette lighter socket (this socket is live on my car i.e. it works even when the ignition is off) or through OBD2 port and leave this connected for days ? Will it harm the battery if left on for too long ? The unit is supposed to have discharge/overcharge protection.

Many thanks for your assistance. Jay

  • 1
    If it is designed to be left connected for a long time, then I assume the manufacture took into account all necessary variables to make it not destroy the battery. The issue is usually that simple chargers will charge at 14-16 volts, instead of "floating" at ~13.5 volts, causing the battery to slowly boil away. Commented Jun 17, 2020 at 16:03
  • I have charged my cars' batteries through the cigar point for many years without problems. It is wired directly to the battery (through a fuse) and as it is intended to run a heating element (the cigar lighter) the amperage isn't a problem, but some of the plugs you can buy have an internal fuse too. It's much easier to put the charger in the footwell than under the bonnet/hood. Commented Jun 17, 2020 at 16:45
  • "The unit is supposed to have discharge/overcharge protection." If it does then you are good.
    – Moab
    Commented Jun 17, 2020 at 17:34


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