Ammo box saddlebags/motorcycle battery lighting system

Discussion in 'Electrical' started by danhill, Oct 15, 2009.

  1. danhill

    danhill New Member

    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.

  2. HoughMade

    HoughMade Guest

    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.

    Attached Files:

  3. danhill

    danhill New Member

    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.
  4. HoughMade

    HoughMade Guest

    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.
  5. happycheapskate

    happycheapskate Active Member

    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.

  6. happycheapskate

    happycheapskate Active Member

    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.