Dual/quad battery setups

Discussion in 'The Projects Forum' started by Dreamglider, Mar 7, 2009.

  1. Dreamglider

    Thread Starter New Member

    Feb 28, 2009
    Good day.
    I Was wondering where i could a drawing/schematic on how to setup two or perhaps four batteries on my boat.(Planning on getting 4 eletric jigging machines in place of the hydraulic ones)
    as of now i have One battery for everything(vhf, echofinder, radar,gps,lights,starter and so on).
    I would like to have two in paralell for the radio/vhf/radar/starter and two for the jiggin machines
    im looking for a way to use just one at a time but charge all at the same time how would i go about doing this ?

    If unclare please say so, i could try to rephrase my quiestion or make a drawing (English is not my native tongue, but i think im ok at it.)

    p.p.s i realy like this forum, just found it a couple of days ago and i know i will be using it in the future, it's just what i was looking for :)
  2. fabelizer

    New Member

    Mar 7, 2009

    Here is a few possibilities for wiring the batteries. Charging is another issue, and is what brought me to the forums. There is alot of conflict on EV sites regarding the best way(s) to charge multiple batteries. I have concluded that ideally, you would charge each separately, unfortunately, that is also the most expensive option! You see, based on a 12v system, you are already series charging 6 cells. If one shorts, the other five are overcharging, if one opens, none are charging. As one cell weakens, the others are affected. Now if you add additional batteries in series or parallel, the probability of an issue increase with the number of cells in the bank of cells, affecting the rest of the cells in the bank. So, thinking you are charging your starting battery out on the water, with several other batteries in the same charging bank, seems to be asking for trouble. At least keep the critical circuits isolated and topped off. Also, for a given charge current, the charge time will increase for each battery added in parallel, even if there are no problems, so your charging source has to be able to provide the needed current to keep charge times within reason. (Big issue with solar...) In my opinion, a selector switch to complete each charge circuit, with the most critical given priority is in order.

    Also realize there WILL be problems if you mix battery chemistries and capacities within the same bank. Batteries within each bank should be matched for type, capacity, and condition (age).

    ...my 2 cents

  3. Dreamglider

    Thread Starter New Member

    Feb 28, 2009
    So i should have one switch for each battery ?

    Perhaps this would be easier.
    Safety first:
    For start/gps/radar/vhf.
    Two batteries in parallel where both are charging, One for use and one as backup.
    (I dont want to be unable to start out at sea again. EVER :/)

    For Jigging:
    Two in parallel use at the same time for max amp/hours.
    The jigging machines usualy draw about 2,5-3Amps but can draw as much as 20Amps each and i have 4 of them.
  4. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
  5. SgtWookie


    Jul 17, 2007
    I'm afraid that an isolator wouldn't work very well inside an enclosure; they need air circulation for cooling. If you're going to be in fresh water only, you might do with an RV unit; otherwise pay the extra for the corrosion resistance of a unit rated for saltwater operation.

    Worth mentioning here is CorrosionX:
    Website: http://www.corrosionxproducts.com/index.htm
    If you're going to be operating in saltwater, you should consider using CorrosionX. The aviation grade lasts much longer than the general purpose grade, particularly for items directly subjected to salt spray.