Ammo box saddlebags/motorcycle battery lighting system

[danhill]

I am sort of combining two ideas I read about here on the forums.

I am very inexperienced in the electrical side of this so let me know if I am getting something wrong.

I would like to build a set of the ammo box saddlebags. These would give me a place to store a battery and mount my taillights.

If I understand correctly I should be able to run a decent watt headlight and my tail lights off a motorcycle batter for 2 or so hours before it is drained.

I am still trying to understand what people use for the turn signal flasher and brake light switch but I am sure a bit more digging will give an awnser.

Any particular mistakes I should avoid? I have read through a ton of posts but my limited understanding of electronic doohickers has only given me a general idea of what I am doing.

 

[HoughMade]

You may not need something as large as a motorcycle battery for this. I use a 7ah 12 volt battery which is smaller than the average motorcycle battery and, on a full charge, should power a 35 watt light for about 2.5 hours. Such a battery will power a 50 watt light for a little under 2 hours. of course, a 10ah 0r 12 ah motorcycle battery would power it that much longer, but you have to weigh the weight/size vs. performance issue for yourself.

Even 20 watts may work for you and at that, a 7ah battery will last over 4 hours.

here are a couple of links that will explain my lighting system.

http://www.motoredbikes.com/showthread.php?t=18278&page=4

http://www.motoredbikes.com/showthread.php?t=20971

 

[danhill]

Thanks Hough! Great info in both those threads, esspecially the smaller flasher relays. Was thinking of canabalizing my old trucks flashers but your solution is much better.

I didn't know that small of a battery would run for so long. 2 hours will be perfect. Do you use a regular plug in trickle charger like for car battery?

I tend to go straight for overkill. am glad someone steers me in the other direction. I already had to talk myself out of trying to mount the battery from my toyota on the cargo rack haha.

 

[HoughMade]

I use a 12v .9 amp transformer for recharging- found it at a thrift store. When I have a full or near full charge, I switch over to a float charger to maintain the charge. I got that for $6 or $7 at Harbor Freight. The float charger will not recharge a discharged battery. I think 35 watts would work for most people, but here have gone to 50 watts. For comparison, a 35 watt halogen light will put out around 500-650 lumens. I have seen cammercially available bicycle lighting systems for well over $100 with 400 lumens and less. The may weigh less and run longer, but you won't get better light at a decent price than what you can build yourself.

 

[happycheapskate]

I am using a 7ah 12v battery. I get them for $5 each new from a battery surplus/remanufactured battery shop in N. TX. The boss says they come off hospital equipment and cannot be used for their life-saving equipment past a certain date since manufacture, forcing new batteries to be replaced sometimes. But they work just fine, and are 20$ cheaper than the ones at Batteries Plus or Phone Shack.

I am using a $10 Bell zipper handlebar bag from walmart, reinforced with a metal bar and hose clamps (the velcro held but the straps tore off)
The battery weighs about 7-10lb. I use one in a padded fanny pack with a helmet light for ATB riding. Its worth the weight (pun) for reliability and power.

 

[happycheapskate]

I charge it by plugging it into a car cig. lighter. The car has a voltage regulator, and I've been using these batteries like this for months. None has ever leaked or overheated.