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Quick and dirty cigarette lighter adapter howto

Old 03-20-2008, 06:36 PM
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Join Date: Dec 2006
Posts: 554
Default Quick and dirty cigarette lighter adapter howto

I was searching this forum for a good howto for installing a cigarette lighter adapter because I would like to use my GPS on the bike when I go on an extended bike trip. Tragically, there simply wasn't a good concise thread on how to do this. So I did my homework and picked up my necessary supplies. All told this project cost me about $20.
An alternative to this method would be to simply purchase a kit from though these cost around $50 and their choice of mounting location may be less than ideal for your purposes. Anyway, lets get to it!

The first thing you will want to purchase is an actual lighter adapter. This one came from my local Radio Shack dealer and cost me approx. 8 bucks with tax. I went with this one because it came with a pre-wired 10amp fuse. If you get a kit that doesn't have a fuse already wired for you, I strongly suggest purchasing a fuse holder and wiring in your own. Whether or not its a blade type or cylinder type makes no difference, but 10 amps is probably the magic number you'll want. PLEASE DISCONNECT YOUR BATTERY BEFORE BEGINNING!!

Depending on how you want to wire the adapter, you may or may not need a relay. If you simply don't care whether or not the adapter is "hot" with the key or engine off, just ground the black wire and hook the positive wire up to the positive terminal of the battery. I would avoid tapping the positive wire off of something like turn signals or headlight, as this may cause the fuse in the fuse box for those accessories to blow, given that that circuit is being over-taxed.
For my purposes, I wanted the adapter to be "dead" when the bike was not running. The thought of forgetting to unplug something from the adapter overnight, only to come back and find a dead battery was enough for me to spend $12 on the next item.

Here is the relay I purchased. This is a 20 amp 14vdc SPST (single pole, single throw) relay. This will allow me to wire everything up such that the adapter is only hot when the ignition is on. If I wanted to be able to defeat this with a second physical switch, I could purchase a SPDT (single pole, double throw) relay, and wire a switch to the additional pin.

This is a simplified version of a schematic I found around the internetz. I deleted some of the clutter and changed some stuff. Originally it was for an FZ1, but the principle is the same.

The diagram itself is pretty self explanatory. Find somewhere nearby to ground the relay and the adapter. I opted to combine the two ground wires into one so I would have a single grounding point. Run the positive wire from the adapter to the post on the relay numbered 30. Likewise run the wire with your 10 amp fuse in it to the battery and connect it to the positive terminal of the battery.

For the last wire, you need to tap off of another circuit that is only hot when the ignition is on. Because it was closest I decided to tap mine off of the left turn signal. The front turn signals will work for this because they are 3-wire lights. They are always on when the bike is running, and then flash brighter when the turn signal flasher is activated. Obviously, since the rear signals are not like this, they won't work, however, the brake light would, should you opt to use that. Anyway, I removed the bulb from the right turn signal and used a continuity tester to determine which pin, and therefor which wire, was a constant source of electricity that I could use to signal my relay. On my F2 it happened to be the light blue wire with a white stripe, the other wire to the b
Old 03-21-2008, 03:53 PM
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Join Date: Apr 2007
Posts: 322
Default RE: Quick and dirty cigarette lighter adapter howto

Light up...
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