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House bank sizing and battery choices-gctid736737

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    House bank sizing and battery choices-gctid736737

    I'm thinking of replacing my boats house bank. This is not an emergency replacement, its part of what I am thinking of as a regular maintenance interval. The Batteries will be 7 years old next season, so this gives me some time to think about it.

    The good thing is that I have a pretty good idea of how we use the boat, and our generator when on the hook which comprises of almost all of our cruising time.

    I do not want to just re-create what the previous owner chose which were four L16HC Interstate batteries rated at 420 Amp hours, and making a 840 amp hour bank. I want to start fresh and determine what would be best for my cruising style. Perhaps that will be what the PO chose, perhaps it will not.

    Starting with my loads...

    With all our stuff onboard we draw between a low of 30 amps to a high of nearly 50 amps DC (not counting the microwave). We average somewhere in the low 40 amp range, with less during the sleeping hours.

    Then we have our charging capacity...

    We have a 150 amp smart charger built into our inverter/charger. We can limit the output as needed to match the batteries selected, but generally I see it max out as a little over 100 amps into the batteries since our loads are still there.

    One of our engines is equipped with a Balmar 150 amp alternator as well. This has a smart regulator and we often see it at around 100 amps into the battery bank.

    Now our style...

    Our generator plays a vital role in our cruising style. Since it is very quiet, and our boat has allot of electric items we do not really really try to minimize its use. Generally speaking we need to run it in the mornings to make breakfast.

    We need a couple hours to make water, and a couple hours to do a load of laundry. In the evening we need an hour or so to make dinner.

    We do not sit in one place all day on the hook. We move around a bit, looking at things, moving from fishing hole to fishing hole, etc... I'm guessing three hours a day minimum is running the main engines.

    My guesstimates....

    Based on all this I'm figuring that we use approx 45 amps average or 1080 amp hours a day of energy thereabouts.

    Our minimum recharge based on our style is

    3 hours of generator time or 300 amp hours

    3 hours of cruising time or 300 amp hours.

    This leaves us with approx 7 hours (calculated) of additional generator run time that we will need on average to replenish what we use for a total of 10 hours a day.

    My real-world generator run time has been only slightly less at around 8 hours a day total, so we're in the ballpark.

    Now to the goals of the battery system...

    [ul]

    [li]A minimum of 10 hours at our low usage time of approx 35 amps, or 350 amp hours is our overnight goal.[/li]

    [li]I want to keep approx the same weight at 480 lbs. I could go a couple hundred pounds higher but don't really want to.[/li]

    [li]We need to keep the same approx footprint. We currently have two boxes side by side of 12X14X 18". We could go a few inches higher[/li]

    [li]The cells need to be individually movable at no more weight than our current 120 lb unit weight.[/li]

    [li]The goal is to match or do better than the current 1475 rated discharges of our L16HC cells. (this number comes from US batteries data sheet at 40% discharge on a L16HC battery.[/li]

    [/ul]

    Other factors...

    I prefer to not parallel cells if possible.

    I am not making price a factor in this equation at this time.

    So... What would you do???

    I'm thinking about the Rolls 4CS17P, or the 21P or the 25P as my first choice options.

    KEVIN SANDERS
    4788 LISAS WAY - SEWARD ALASKA

    #2
    Seeing as how we are spending your money Kevin, have you considered lithium batteries? Lighter, fast charge times,higher capacity, for their size.

    I would be interested to hear your thoughts on them in any case.
    Joel
    1987 3818 Hino 175
    "Knotty Girl"
    Prince Rupert B.C.

    Comment


      #3
      "canoel" post=736742 wrote:
      Seeing as how we are spending your money Kevin, have you considered lithium batteries? Lighter, fast charge times,higher capacity, for their size.

      I would be interested to hear your thoughts on them in any case.
      I have not looked into them, but will. Do you know of a house bank size lithium battery?

      Isnt there an issue of these catching fire???

      KEVIN SANDERS
      4788 LISAS WAY - SEWARD ALASKA

      Comment


        #4
        Kevin - I've been contemplating replacements for my house bank as well which is currently 6 Deka GC15 golf cart batteries. I have 645 Ah capacity with this setup. I really like your LH16 config. It looks like I can replace my 2 battery boxes with a single one that holds all 4 LH16's. This will simplify cabling and ease of access. LH16's seem to be a bit more difficult to obtain and are of course more expensive than the GC15's. But isn't that what boating is about!
        Evan
        2001 Bayliner 4788 "Fifty / Fifty II"
        League City, TX

        Comment


          #5
          Here are a few articles. They also maintain a more constant voltage during discharge. The benefits are many, however the cost is high.

          I think the fast recharge rate, and the ability to run them down more than a flooded or agm, would possibly allow a smaller bank with less amp hours.

          http://www.powerandmotoryacht.com/re...hium-batteries

          http://www.lithiumion-batteries.com/...-batteries.php
          Joel
          1987 3818 Hino 175
          "Knotty Girl"
          Prince Rupert B.C.

          Comment


            #6
            Hi Kevin,

            Why so exotic on batteries? I just redid my house bank with 8 Interstate batteries and have plenty of reserve and charging ability. The detail of your post makes me think I'm either missing something or don't know something. If I remember your gen is a NL 12KW? So you would have plenty of power to recharge with gen or alt running. I think my bank is prob in the range of 152lbs heavier which is a big difference

            If you had three of the Rolls batteries wouldn't your total AH be 770 at 12v so, useable would be 385? The interstate bank of 8 batts although heavier would yield more AH at 464 (the most common batt T-105 is similar). Are you thinking of doing two banks of the Rolls batts or would that be over kill since you don't spend a lot of time in one spot so you don't need long reserves.

            Derek
            Family Boater
            1997 Bayliner 4788 w/330 Cummins - Phoenix
            (past) 1987 Bayliner 3218 w/135 Hino - True Story

            Comment


              #7
              Thanks Derek,

              I'm not really trying to complicate things, I'm just trying to make sure I get the right thing for the boat.

              If I went with the midsize rolls batteries they would give 685 amp hours of capacity. If you figure my maximum drawdown would be 40 A times 10 hours or 400 amp hours than what I'm showing is that I should get somewhere around 2000 to 2500 cycles off of the battery bank.

              That's compared to 1100 and something cycles off of my current battery bank.

              Buying the two rolls batteries would run something around $1000 each or $2000 for the battery bank. I don't remember the exact price for the L 16 HC's but I thought it was something a little less than $400 or $1600 total.

              From strictly a money standpoint I think the rolls would be a good deal, but not so much of a great deal to be a big deal.

              I did hear about a recent boat fire that was caused by a parallel set of batteries were one shorted and the good battery fed the short causing a big battery fire. That is a consideration, but I really think that's a pretty rare occurrence.

              KEVIN SANDERS
              4788 LISAS WAY - SEWARD ALASKA

              Comment


                #8
                So you should not discharge below 50% level of your batteries.

                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 350 amps back into your batteries as efficiently as possible, you need the charging system giving you its highest output for the full time your charging

                So if you need 350 amps between charging, that's the number you need to be 35% of you battery bank capacity (85-50=35).

                This means you need a minimum 1000 amp-hr battery bank to allow you to operate in the band of 85% to 50%.

                My battery bank is close to your numbers, bu not of the configuration you're looking for:

                - I have 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 get 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)

                Just one example of what's being used.

                I'm sure there are other configs that will get you closer to your requirements/parameters.

                But it might rely on newer technologies or ones that might not give you a the best value

                (twice the price but at only 50% performance improvement wouldn't cut it for me)
                Pat
                Paragon
                1999 4788

                Comment


                  #9
                  Pat - Are our battery banks the same basically then (if you saw my recent post)?

                  Kevin - Cycles look to be the key...it looks like the Rolls batteries will last twice as long which is a good thing so I could see why you are considering them. What about availability? Are they ship in only or can you find locally like an Interstate or Trojan? That might be a concern IF you were to have a warranty situation (very rare though).

                  Derek
                  Family Boater
                  1997 Bayliner 4788 w/330 Cummins - Phoenix
                  (past) 1987 Bayliner 3218 w/135 Hino - True Story

                  Comment


                    #10
                    Derek - yes, we have the same battery bank.
                    Pat
                    Paragon
                    1999 4788

                    Comment


                      #11
                      Just something else to think about. Solar. It should work well on your long summer days. It might help get you through your down time.

                      Doug
                      Started boating 1955
                      Number of boats owned 32
                      Bayliners
                      2655
                      2755
                      2850
                      3870 presently owned
                      Favorite boat. Toss up. 46' Chris Craft, 3870 Bayliner

                      Comment

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