Charging SLA battery through permanently attached cable

Discussion in 'General Electronics Chat' started by Fazzzeled1, Oct 7, 2014.

  1. Fazzzeled1

    Thread Starter New Member

    Oct 7, 2014
    I want to charge a 12 volt, 20 Amp hour AGM SLA battery through permanently attached cables. I think this is sometimes called a battery harness. (Maybe)

    It is a small marine battery I will be using in calm ocean waters in a small kayak to power a 18 lb thrust trolling motor. If I can permanently attach the cable it allows me to do a much better job of waterproofing all the connections.

    To charge this I am using a smart 4 stage microprocessor controlled battery charger. It says it is 12 volt , 3.3 amp. I have been directly clamping this onto the battery terminals when I need to charge this battery.

    Here is a link to the charger I am using.

    I am concerned that if I try to charge the battery through the cables I recently attached, something in the permanent cables I have created and attached may interfere with the chargers ability to read the batteries condition and apply an appropriate charge.

    I uploaded a couple pictures, with an explanation of what I am trying to do into a google document.

    I could not see a way to include a picture from my camera, and I hope this works.

    I have no experience with trying to wire anything to a 12 volt battery, or any other electrical systems. I have done a lot of reading, and I have spent almost a week trying to find a definitive answer to this somewhere, but I have had no luck. Maybe because it is such a simple question no one who needs to know this, is so clueless they need to ask.

    But I do not want to assume I understand how all this works, and fry my battery. Or worse.

    If anyone here could tell me if it should be OK to charge my battery through this harness I built, I would really appreciate it.
  2. alfacliff

    Well-Known Member

    Dec 13, 2013
    hopefully the now permanantly attatched cables are large enough to handle the current of the motor which is higher than the charge current. shouldnt add enough voltage drop across the cables to interfear with the charger.
  3. Fazzzeled1

    Thread Starter New Member

    Oct 7, 2014
    Thanks so much for responding to this!

    The motor supposedly draws 15 amps on high, and the wire between the battery and motor is 6 feet.

    2 feet of the wiring that is in the disconnect that I added is 10 gauge, and 4 feet of the original wiring is 12 gauge. Originally there was 5 feet of 12 gauge, and the manufacturer recomended installing a 50 amp inline fuse.

    Because I have added a foot to the wiring using a heavier gauge, , I made a researched guess that a 30 amp fuse should work to protect the additional length of wire, and should still work with the motor...

    My main concern has been how my wiring could interfere with the smart charger... But if I am wrong about the amps this gauge of wire can carry 6 feet, it would be something I would appreciate knowing about before I start melting things...