# Power Calculations, need confirmed

Discussion in 'Electrical' started by scubaru89, Oct 3, 2012.

1. ### scubaru89Member

I've had the bike up and running now for 3 weeks, and I knew from the start I wanted to have an awesome light system. Since I first started using it I've had a 4 LED headlamp zip tied to the handle bars, you literally cannot see my front tire with the light.

So I've started building my ultimate lighting system, and I want to make sure my numbers make sense and maybe someone can give me some advice on a mobile charging system.

Lighting:

35W @ 12V HID Kit

Start-up: <6 amps

Running: 3.4 amps

Battery:

AutoCraft 4L-BS

Voltage: 12V

Amps: 10Ah

In a perfect world I would have 10Ah of power, the HID kit would run for 2.94 hours. However I was told to only calculate for 50% of the stated Ah if the draw is over .5 amps. So that means I'll have 1.47 hours of operation in a perfect world. I do luck out in that my longest commutes is 15 minutes. I have a 1.5A charger at home that will be used as often as possible to keep from killing the battery.

Now on-top of this I will also be running a tail/brake light, I got one for free and hope to have all the LEDs working on it here soon, the power consumption is to be determined on that one. I would also like to run a strip of LEDs shining on the engine for better visibility at night, that pulls .29A @ 12V.

So given my numbers, should I be able to at least have a working system for the 15 minute commutes I do every few times a week? What would be a good charging system?

I have been looking at "Wonderful Creation" on ebay, they have some of the 12V alternators that work with the magneto. Problem is they will produce somewhat of an AC current. Are there other methods or way to streamline that current to a working DC current to charge my battery? Am I looking at any issues cause its a lead acid battery?

<
2. ### jaguarWell-Known Member

god man, why are you doing it the most difficult way? JNMotors sells a 21 LED headlight/taillight combo that is very bright and very light on battery consumption for only \$16. I've got just 9 LED on my front end and I think it's OK, but not great. To make it self sustaining then just find a small solar panel that you can connect to the 3 AAA batteries (rechargable of course) and you will probably never have to recharge them outside of the system. That's what I did. Love stuff that you never have to touch again!

3. ### scubaru89Member

I'm an engineer, I need a challenge. Plus it will produce over 2000 lumens of light.

4. ### loquinActive Member

Challenges are good. But, while that much light is needed when you're driving in a car or motorcycle at 60 mph, on a bike, even at 30 mph, you only need a quarter of that to be able to see far enough ahead to stop... (and 500 lumens is easily seen by others)

5. ### scubaru89Member

I like the quote "Go Big or Go Home". In all the battery and wires were \$30, the projector \$25, and the HID kit was \$25. Not a bad price for what I'm getting out of it.

Here are some pictures with a Halogen bulb while I'm waiting for my HID kit to get here.

http://i776.photobucket.com/albums/yy49/subaru_steve/Motored Bike/PhotoOct0974540PM.jpg

http://i776.photobucket.com/albums/yy49/subaru_steve/Motored Bike/PhotoOct0974603PM.jpg

I'm brighter than some cars, haha.