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Advice for installing new 8V batteries

Discussion in 'Technical Discussion' started by Ed Tillett, Apr 7, 2016.

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  1. Ed Tillett, Apr 7, 2016
    #1
    Ed Tillett

    Ed Tillett New Member

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    I'm replacing four 8V batteries in my boat and need some advice. The previous owner installed dual-purpose batteries. And, from what I understand, one of the alternators on the 671s charged the bank, in addition to a Newmar perfect wave converter/inverter. The boat was just delivered to me and the new Eastpenn Deka Marine Master batteries are "cooked." I don't know why - overcharged or not maintained. But they were only 6 months old. So, should I go with dual-purpose or deep cycle? I have two 12 volt AGMs for starting the engines, so I don't believe the 32V are needed for that effort. I'm still unraveling the logic (or lack thereof) of the system, so might answer my own question, soon. In the interim, any advice is welcome.
  2. Loren Schweizer, Apr 7, 2016
    #2
    Loren Schweizer

    Loren Schweizer YF Associate Writer

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    The experts on this situation would be Ward's Electric in Fort Lauderdale, FL.
  3. Capt Ralph, Apr 7, 2016
    #3
    Capt Ralph

    Capt Ralph Senior Member

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    Grab an aspirin and hang on.
    Countless boats I have worked on frying batteries have come down to alternator sense or alternator enable issue. Or some event causing a overcharge to happen to your batteries.

    Usually older boats.

    Now follow this; At the helm many feet away from the battery is the key switch (32Vdc boats may just be a switch), It enables a purple (or switched hot) wire. This same DCv hot wire enables the gauges and engine alarms. Then a lead goes way back to the alternator voltage regulator enabling it and giving a voltage level for the alternator to bring up the voltage. Then the alternator out put is tied to the battery, usually by way of the starter/battery cable.

    Thru the years this long run of wire develops a resistance (crimps, connects, green) and the enable wire, even though the battery is already at 33Vdc has a enable signal of 28Vdc. The regulator lets the alternator to pour it on to what it thinks is a low battery. Now charging up to 36,38+ Vdc. Your new battery is getting over charged.
    (same issues for 12 & 24Vdc systems)

    Changing batteries is not going to fix this.

    I use the Deka 19 inch, 8V batteries and love them. With just some care, they will last many MANY years.

    Now your going to tell me the volt meter on the dash displays normal. BUNK.
    It's tied up in this same mess and reading a voltage after some resistance, half way to the alternator regulator.

    If you have direct mounted Leece Neville alternators on your 671, I can tell you, above is your problem.

    A switch exciter wire on your Delco, Motorola & Prestolites will do the same.

    Post some pictures of your alt including any wire connects for some fix ideas.
    ,Ralph
  4. Ed Tillett, Apr 8, 2016
    #4
    Ed Tillett

    Ed Tillett New Member

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    Ralph:

    Great insight!! I'll start running that down later today. This is an older boat and there's quite a morass of wiring under the helm. I'll start tracing it and see what I come up with. I'll drop some photos to you if I get flummoxed.

    Ed
  5. Capt Ralph, Apr 8, 2016
    #5
    Capt Ralph

    Capt Ralph Senior Member

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    There are some easy fixes pending the exact alt model.
    ,rc
  6. Capt J, Apr 8, 2016
    #6
    Capt J

    Capt J Senior Member

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    You really need to remedy why your batteries are getting cooked. Many times I've seen the charger leaking AC voltage and frying batteries and always check the leads with a multi meter if there's a battery issue. Generally I've found even if a alternator is overcharging it doesn't cook the batteries because most boats are rarely run, but it's a posibility also. No sense putting new batteries only to get the same. What does the water level in the batteries look like? Not adding water in 6 months can also fry a new set of batteries.
  7. Capt Ralph, Apr 8, 2016
    #7
    Capt Ralph

    Capt Ralph Senior Member

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    Skippy J has well documented chargers frying batteries in the past.
    This is also in need of looking into.
    I have witnessed it happen once when a deck gutter was restricted and water poured into the charger below it.

    It took an O'scope to see the big picture in my issue since some multi meters can not give you the whole story and lots of chargers still produce a ripple on the DCv output normally.
  8. Capt J, Apr 8, 2016
    #8
    Capt J

    Capt J Senior Member

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    I also have had a dozen Newmar chargers go bad over the years and cook batteries, one was a pt2495 (95 amps) that went bad at 6 months old.
  9. Pascal, Apr 8, 2016
    #9
    Pascal

    Pascal Senior Member

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    I m confused with the last part of y r post, wpabout having two 12 v batteries to start the Detroits so the 32v isn't needed for that.

    Are y saying that the engines are 24v but the house bank is 32v?

    If so, then any deep cycle battery will be fine for your 32v house bank.

    First y need to know why the batteries are cooked in just 6 months.... Two possibilities..l either your charger is overlooking them or water level have not been checked. What kind of charger? Smart multistage or old ferro? With an old charger yachtcharmer will need to top them off every month. With a modern smart chargers, every 3 to 6 months.

    Have you checked water level? Start there... Top them off, charge them and see what happens. Then decide.

    Personally for house banks I m a big fan of golf cart batteries, they are deep cycle, smaller to carry (60lbs or so) and can take a beating. They come in 6 or 8 v. They re about 220ah so 4 in series will give your 32v and 220Ah. If that's not enough, depending on what you need and how you use the boat, you can add another set of 4 (or more) in parallel I get 4 years out of them on my boat.
  10. Loren Schweizer, Apr 8, 2016
    #10
    Loren Schweizer

    Loren Schweizer YF Associate Writer

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    Not mentioned thus far in this thread, but certainly worth noting, is that elderly Bertrams (and Hats & others), such as Ralph's 58, have a 32VDC system with a floating ground.
    If there has been any electrical tech onboard adding/modifying something not paying heed to this, it could be problematic.
  11. Ed Tillett, Apr 9, 2016
    #11
    Ed Tillett

    Ed Tillett New Member

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  12. Ed Tillett, Apr 9, 2016
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    Ed Tillett

    Ed Tillett New Member

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    Ok, gents. Some good advice and follow up. I just took delivery on the boat. The delivery captain told me that the batteries went dry (who knows when? - either before he left or during his two-week trip). I think the problem was as simple as the previous owner did not maintain the batteries. In any event, I'm running down the configuration of the system. I'm fairly certain that the 12V AGMs on board start the engines. Either 12V each engine, or 24V combined. I'll confirm that, but believe that it's 12V each. As far as the 32V house system, back to my original question, which Pascal answered: 32V deep cycle versus dual purpose batteries are preferred, which is what a rep. from U.S. Battery suggested the other day when I spoke with him. The Newmar has been sent to the factory in St. Paul for evaluation. And, to Ralph and Loren's points, if the charging system is jacked up, I can buy all the batteries I want - again and again. So, I'm working with the yard electrician to figure this out. By the way, Ralph, I don't have a switch, just a couple of start buttons. The boat is 1947 vintage. Appreciate all the insight. I'll revisit this thread and post the findings and solutions when I figure things out. Thanks, again.
  13. Pascal, Apr 9, 2016
    #13
    Pascal

    Pascal Senior Member

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    Captain noticed teh batteries were dry but didnt top them off with water? You got to be kidding...

    Is the boat in the water? I wouldn't sleep well at night with dead battery and no charger to run t bilge pumps in case something happen while the charger is being repaired. Especially on a new to me boat... all it takes is one hose clamp failure to send it to the bottom of the marina.

    Make sure you check the bilges daily and close all sea cocks.
    Last edited: Apr 9, 2016
  14. Ed Tillett, Apr 9, 2016
    #14
    Ed Tillett

    Ed Tillett New Member

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    I believe that he noticed AFTER they were dry. Then, of course, they were filled. But, too late!! No issues with the batteries and charger being inoperable now - except the cost of buying new ones. She's on the hard for another month, or so. That's why I'm running down the system so I can put it back in the correct configuration. So, I see my check list as:
    1. Buy new batteries (deep cycle if they are not needed to assist starting, which I'm sure they aren't)
    2. Determine alternator / V regulator status (per Ralph) so that correct charge is occurring when underway
    3. Confirm that the Newmar is operable (at the factory now for eval)
    4. Keep the batteries serviced

    Thanks.
  15. Ed Tillett, Apr 13, 2016
    #15
    Ed Tillett

    Ed Tillett New Member

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    More advice needed, gents. The Newmar charger/inverter can be repaired by Sensata Technologies. However, Newmar is no longer producing a 32V version and repair parts are thinning out. I'll spend about $800 to get it repaired. No problem. I've considered moving to 24V, but see from your threads and postings 10 years ago here that it's 6 in one / half-dozen in the other. I thought about going for 24V LED house and running lights - but don't know that I want to start changing out every socket in the boat right now. I still don't know what 32V pumps, heads, etc. I have because I haven't had it long enough to run the rabbits. So, let's move those exercises to the right on the schedule, and focus on getting powered up following the burnout of the 4 Deka 8Vs on board, which were dual purpose, but are not needed for starting the DD671s. How about if I put 4 deep cycle 8V golf cart batteries in that deliver only 165AHs? Or, foolish me, put in 8 deep cycle 8V golf cart batteries serial/parallel and get 330AHs? Is this OK? Questions are: Do I need more than 165AHs? I haven't inventoried my on-board watt/amp requirements yet, so I don't know what amps I'll burn. And, since the boat is new to me, I don't know how much time I'll spend on the hook. But I want power when I do. I have a genset, but it's very old and loud and leaky. So, I can't depend on it. Thanks for the help.