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4788 House Battery-gctid817775

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    4788 House Battery-gctid817775

    Any suggestions or opinions of what type of house battery is best for a 4788?

    Thanks - Bob

    Lots of previous discussions on this topic. Some prefer the L-16. Some like GC batteries like the T-145. I prefer using a size I can handle without help. The ones in my 3270 are grp 29 12 volts in parallel. A customer wanted four of the T-145 in series and paralleled to 600 amp size terminal strips. It also makes sense to use what is readily available at home and your favorite cruising areas. Same goes for starting batteries. Customer wants to cruise SE Alaska so we called around to shops there to find out what they regularly stock and made the decision from that information.

    Newport, Oregon
    South Beach Marina
    1986 3270 with twin 110 HP Hino diesels. Name of boat "Mr. Darcy"
    Past work history: Prototyping, tooling, and repair for Reinell,. General fiberglass boat repair starting in 1976.
    Also worked as heavy equipment mechanic, and machinery mechanic for over 30 years.


      Hi Bob, hard to give a good answer without more info. First would be what size of house bank do you need? That depends on where and the type of cruising you do, as well as your daily amp-hour demands on the house. For example, boater in the PNW that typically don't need aircon and anchor out a lot need a large enough bank to at least see them through a night without the genny on, without dropping below 50% charge on their house bank. That typically puts them somewhere in the 600-900 amp-hour house capacity requirement. However, if you are somewhere where you need aircon and run the generator most of the time, or your cruising is typically marina to marina with dock power, then you can get away with a much smaller bank.

      For larger banks, lead acid is still the value standard, usually multiple six volt batteries for their smaller size and convenience getting them into and out of the boat. However, they require regular watering and are most susceptible to damage if discharged below 50%. AGM batteries are approximately double the price per amp-hour, but don't need watering and can be safely discharged a little lower than 50%.
      "Allante I" Rayburn 75
      Previous: '97 4788


        I have 6 golf cart batteries in 2 8D battery boxes (3 per box) that gives me 645Ah capacity. The main thing I like about the golf cart batteries is that they are relatively inexpensive and available at most Costco stores. I took a very hard look at switching the L-16 batteries which would have given me about 800Ah capacity with just 4 units. But could not justify the extra cost and project hassle given the types of boating that we do.
        SOLD - 2001 Bayliner 4788 "Fifty / Fifty II"
        2006 Meridian 580 - “Amnesia”
        League City, TX


          We spend allot of nighs on the hook in our 4788.

          We also have a pretty high power draw, with the satellite comm. pod, and deep freeze, furnaces, etc...

          This results in an "average" draw of approx 35 amp hours.

          All that said our 820 amp hour bank coupled with a 150 amp charger is a good fit.

          We can run all night on the hook, get up and start the generator. The bank recharges in a reasonable amount of time.

          To get that amp hour size we have four L16-HC batteries

          If your boating style, and your consumption allows for a smaller bank, of course that is better for several reasons.


          Whats the weather like on the boat

          Where am I right now?


            You should not discharge below 50% level of your batteries AH rating.

            And most chargers and alternators start to scale back at the 85% battery level (you will not get 100 amp/hrs from your charging when above 85%)

            If you want those amps back into your batteries as efficiently as possible, you need the charging system giving you its highest output for the full time you're charging (generator running or engine alternators)

            I have an 880 AH bank, so have 310 AH to operate between the 85% and 50% band.

            We typically use around 200 ah between charging, so two hrs of charging gets it all back and I have cushion on both sides.

            The bank is qty 8 6V batteries in in parallel/series configuration, total weight 520 (8x65lbs)

            We used to have qty 6 6V batteries and were always in a losing game with 2 hrs charging.
            1999 4788