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36 convertible electrical issue

Discussion in 'Luhrs Yacht' started by Nick Khoury, Jun 13, 2020.

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  1. rtrafford

    rtrafford Senior Member

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    Recommend you don't go back to sharing house & starter. Recommend you shift to 31 series starting batteries and then you can even eliminate the 8D's and shift to a smaller modern battery for house. House and starter sharing is a recipe for a bad ending. You could go to Odyssey 31 series for everything and have less maintenance and weight than the 8D.
  2. Nick Khoury

    Nick Khoury New Member

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    The batteries are less then year old. The previous owner replaced them because during test run we had the same problem on port engine and previous owner replaced batteries. Although we found out that folded laminated plastic shoved into electrical box of the engine was the issue. The previous owner put Napa truck batteries 8d with 1335 cca instead of marine batteries. I see why because they are half the price but also have 140 mins less reserve. I believe this is why windlass killed battery so quickly. This is first boat I've ever owned that house batteries are not separate from engine. Very poor design. I always run generator with charger because I read that cats alternator at low rpm isn't sufficient amp to recharge if running lights, fridge, and some other essential dc item's.
  3. Nick Khoury

    Nick Khoury New Member

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    I agree but will have to figure out how to separate I traced the wires going to grounding block. Unfortunately they are on port bulkhead aft of engines and there isn't access because generator and exhaust of port engine block me from getting to it. Eventually I'll have to disassemble exhaust so I can gain access and determine how to separate. For now I'm going to switch to marine 8d batteries with lager reserve.
  4. Nick Khoury

    Nick Khoury New Member

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    Thx I did that before diagnosing the electrical short. Every terminal cleaned put back tight and then I put dialectical grease on top.
  5. DOCKMASTER

    DOCKMASTER Senior Member

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    Just having truck batteries vs marine is not why your windlass caused a problem. You have something else going on. Was your generator also running with a/c fed charger going? You really need to do a full charging system analysis and then figure out what is drawing your batteries down. And yes, find a way to separate your house DC needs from your engine starting needs....quickly!
  6. cleanslate

    cleanslate Senior Member

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    They are not the right 8D batteries from Napa.
    I have NAPA 8D , part # BAT 7271FT; in my boat which is for the motors and the house and I never have any issues.
    They are made by East Penn.part # 908DFT.
    1425 CCA; 440 min reserve capacity.

    I have two Detroit diesel 4 71s ; a three cylinder 8KW generator etc, and an Ideal Windlass . I don’t experience any dead batteries or issues when using my Windlass anchoring.
    I usually get five years out of the batteries.
    there is no such thing as a marine wet battery other than the label that’s slapped on it that says Marine.
    that same battery is also used in commercial trucks , farm equipment , industrial equipment etc.
  7. SoCal340

    SoCal340 New Member

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    Our Tournament 340 is configured the same way, which adds some complexities.
  8. bluebyu

    bluebyu New Member

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    I second what Cleanslate says about marine label.
    Several years ago I spoke with East Penn, only difference between truck and marine batteries, the label.
  9. KevinMC

    KevinMC New Member

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    Kent Island, Md

    My T350 with Cummins 370B’s are also configured the same way - not optimal as the experts have stated here, but its the way the boat was built - It is what it is!

    Couple of points here on how I manage this to prevent any battery drainage that would affect starting the engines:

    1). On the Electric panel there are a couple of Switches that let me choose which battery to use as house (PORT or STBD) I swap every month or so to switch the loads. Maybe you have that same set of switches on the electrical panel.

    2). Instead of 4d or 8d’s I have installed twin group 31’s for each side. Using the Interstate 31-MHD’s (950 CCA)wired in parallel for each side(total of four batteries) gives me 1900CCA per side. Have a separate starting battery for the generator. The Group 31’s are a LOT easier to lift than 4d’s. I’ve been getting 5-7 years of Battery life using this setup. When time to replace, I replace both batteries in a pair.

    3. When anchored out for an extended period, I’ll run generator to charge up batteries, just as a safety measure and piece of mind.

    4. Finally, the Parallel switch on your helm, if working properly, should gang all of your batteries together ( in my case 4) to provide enough CCA to start the engine without needing to jumper.

    Hope this gives you some ideas!
    Kevin
    Last edited: Jul 14, 2020