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  1. #1
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    12v parallel question

    I'm setting up my boat for a 12v TM and want to use two batteries in parallel. I was thinking of running the two positives to a busbar and two negatives to another busbar, from them the power could be taken forward to the TM. Where I keep the boat there is no power, so I want to be able to unhook the batteries easily, so I think doing it like this, with anderson connectors, would be the best solution. Just want to check that there is no practical difference between linking the positives directly to the battery terminals as is usually illustrated. Hope that makes sense.

  2. Electrical/Wiring/Trolling Motors Moderator CatFan's Avatar
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    #2
    I'd make absolutely sure you have circuit protection before the wires get to the bus bars. You have a high risk of something making contact with both and things getting ugly.
    If you have integrity, nothing else matters. If you don't have integrity,
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    #3
    The bus bars will have covers, but understand your point. I have a 60a breaker which I was going to put immediately after the bus bars, but do you think I should put a 60amp breaker on each positive before the bus bar?

  4. Banned
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    #4
    Quote Originally Posted by Tim Kelly View Post
    The bus bars will have covers, but understand your point. I have a 60a breaker which I was going to put immediately after the bus bars, but do you think I should put a 60amp breaker on each positive before the bus bar?
    pretty sure you want the breaker as close to battery as possible, between the battery and busbar. Also, because you are using both batteries as power source, you'll need both breakers, one at each battery.

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    #5
    Hmmm. That's OK, but if one breaker is tripped I wouldn't realise and would draw down one battery without realising the other wasn't working. I wonder how I could make it obvious that one breaker had tripped as they can do when you connect the battery or maybe in transit?

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    #6
    Both batteries if being parallel configured would require overload protection and each need it at/near the battery's positive terminal. You are correct that if one tripped, it could go unnoticed until the single battery left in circuit had became over-discharged and possibly permanently damaged.

    If a single 12 volt battery cannot provide you with the needed power, consider upgrading to a 24 volt "digital' trolling motor utilizing two large capacity deep cycle 12 volt batteries connected in seriesand utilizing one breaker.
    Last edited by Lou r Pitcher; 03-23-2018 at 04:06 PM.

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    #7
    That's OK, except I have a 12v bow mount and a 12v transom mount motor already. It's only a small boat, but I can wear out a single 12v easily in a day.