Trying to determine if 2007 civic OBD2 port is live with key off so I can trickle charge with a solar panel

  • Welcome to Motor Vehicle Maintenance & Repair! Jan 10, 2020 at 14:20
  • just because some thing is possible does not mean you shuld do it,it might be better to connect the charger to the plus on your ignition switch. Jan 10, 2020 at 14:20
  • It's not what you ask, but I charge the battery through the main cigar lighter point, which is always live. This works on both my cars, one is 16 years old, the other is 3 years old. I replaced the battery clamps on the charger with a cigar-socket plug, making the recharging job much easier (I shut the car door with the mains cable at the bottom corner away from the hinges and there is plenty of room in the footwell for the charger). The cigar point being what it is - for a heater element - it can handle a normal charging current. I don't attempt to activate the ignition etc. while I do this. Jan 10, 2020 at 16:03

1 Answer 1


The 12v pin on the OBDII should be constant on regardless of the key position. Here is the pin out:

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You can test it with a multimeter to ensure it is this way in your vehicle.

Whether it will work for trickle charging with a solar panel has yet to be seen, but always worth a go.

  • 1
    Pretty much this. It's worth bearing in mind that the wiring to the OBD port isn't generally high-gauge stuff, a low-current (<1A) float charger shouldn't be a problem though. Jan 10, 2020 at 14:51
  • The device is a purpose built Coleman solar trickle charger, sounds like it should work. Thanks Jan 10, 2020 at 15:15
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    @edwardpeters - If this answers your question, please consider an upvote and select as the answer. Jan 10, 2020 at 15:20

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