There's another thread here discussing charging an iPhone through an AC converter. And there was a thread on the old forum about making a 5v adapter for a camcorder. This thread touches on both. I installed a BMW style power socket on my ZX14 about a year ago, and made up three cords to plug into it, one for a regular automotive cigarette lighter socket, another for a two-prong power cord for a small air compressor, and another to charge my iPhone. The BMW plugs are significantly smaller than your standard DC cigarette lighter plug, and the socket side looks much cleaner on the bike. Both plugs and adapters are available from Aerostitch.

Since the iPhone wants 5 volts to charge, I had to build a small voltage regulator circuit into the plug itself. The iPhone cord started life as a Griffin mobile charge cord. I lopped off the cigarette lighter plug, figured out which wire was ground and which one was live, and just wired her up to my little regulator circuit.
The adapter creates some heat, so the plug gets hot, but after running it at least 10 hours straight, and for over 60 hours last week, I think it will handle the fine.

As posted on the old forum, here's the regulator circuit. The bypass capacitor on the input side isn't absolutely necessary, and I left it out of the circuit I actually built to save a bit of room, and it works fine. The capacitor on the output of the regulator is there to reduce the chance of self-oscillation in the regulator, which wouldn't be good. If your device needs 6 volts, use a 7806 regulator chip instead. If you need 9v, use a 7809. For 12 volts, a 7812.

In the schematic, the input side of the 7805 regulator would be connected to the hot (center) pin of the BMW plug. The output side is where the hot side of the iPhone cord is wired to.

I ran a separate 10 gauge line from the battery to the power socket. It has an inline fuse which is replaceable by removing the plastic panel that hides the battery. I tapped the same line to power a big horn. So far so good. My only real caution is that the metal part of the air hose on those little compressors get REALLY hot when the thing runs for a few minutes.

-Matt

* Last updated by: MattTheHat on 7/6/2009 @ 7:34 PM *

Matt,

I may have an electronic "project" for you to build if you are interested.

Being that you seem comfortable with designing your own circuits, I need a wig/wag 2 circuit (adjustable rate?) A/C controler rated for 20W.

Interested ????

Send me an e-mail if you are.

Beondwacko@yahoo.com

Thanks

Adam

Oh, man, Adam, you DO NOT want me designing *any* kind of circuit for you, that's for sure! That regulator circuit is pretty standard stuff, there's lot's and lot's of smarts handled inside that chip. Strictly speaking, the bypass capacitors aren't usually even needed. To give you an idea, that chip does as much as much of the larger 16-pin regulator chips, and those chips require a good number of external components as well.

That being said, whatcha needing to do with the wig wag circuit? I installed one of those Back Off wig wag signal things to my ZX14 and had zero problems with it. Depending on what you need it for, there may already be an ready made solution. (I've seen some wig wag circuits with built-in relays for commercial hazard lighting and such. With relays, they'd certainly handle a lot more than 20 watts.)

-Matt

HI there Matt;

I was looking to control a walk/don't walk sign I have with a transistorized circuit that I can vary the time of energizing one leg, then the other. Being that the symbols are LED's and the total draw is only something like 12 watts total, it wouldn't need anything HD component wise. I just wanted a plan to have then alternate every 10-20 seconds or so but without the noise of relays clicking in the backround.

I was hopefull tha you might be able to design something like that and that I'd build it, or maybe even pay you to build it. I can buy one commercially made but in these tough financial times, you know.

Adam

I'll drop you an email, that might be something that's not too difficult.

-Matt