The answer to this may be so obvious that I'm almost too embarrassed to ask; however, here goes:

I have a high-end battery charger for my car which charges through the cigarette lighter receptacle. I want to use the charger on my motorcycle which has two (2) ports - one in a rear case and one on the front fairing. As a preliminary test, I plugged my phone charger into each port. The charger has a red light. With the motorcycle's ignition "off", the red light does not light; it only lights when the bike is running.

Am I correct in assuming that, since no power is outputted when the bike is shut off, no recharging will occur either?

  • 1
    Yes. Most vehicles disconnect the battery when the ignition is off to prevent the battery from discharging itself overnight. No one wants to wake up to a dead car battery.
    – ACD
    Commented Nov 6, 2014 at 18:44
  • 1
    Ha ha ha, so typical. Can't have a question that is even a shade out of the bounds of this exact, specific, little thing that I've defined for my StackExchange(SE). No wonder people are being turned off by this site. Commented Dec 2, 2016 at 20:07
  • Can you tell me where you got your charger?
    – Mawg
    Commented Dec 16, 2016 at 9:45
  • I'm not sure I'm doing this correctly, but Mawg asks where I got the charger. Since the charger was specifically a BMW product, and because I was [dubiously] persuaded that this was the only charger that would work with the CANBUS system, I recall that I bought the charger directly from BMW Motorcycles.
    – Pat
    Commented Dec 19, 2016 at 15:04
  • @ACD Not completely "disconnected." Otherwise, your fuel trims, stereo presets and alarm wouldn't work.
    – 3Dave
    Commented Dec 19, 2016 at 16:12

2 Answers 2


Depends on make and model. Some cars come with cigarette/accessory power outlets that are keyed, some come with outlets that are always on, and some have both.

Keyed outlets switch on and off with the ignition switch position. That switch powers a relay that turns on power for most accessories.

An always on outlet is a straight (fused) connection to the battery. You can get a kit for a few bucks at any auto store.

To find out the exact wiring for your motorcycle, find the wiring guide or schematic in the factory service manual.


Since there isn't a connection when the key is off, the battery isn't going to charge.

Most of the float chargers I've seen, has several different attachment methods. With the one I had, it included a direct connect to the battery which had a quick disconnect. If the one you have doesn't have something like this, you can always pick up a separate one for about $20. Just plug it in when you're not riding the bike.

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