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Re: [SabreSailboat] DC system in Sabre 362

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  • Dave Lochner
    Ray, It appears that you have 2 6 volt batteries in series. That makes 12 volts. Dave Sent from my iPad
    Message 1 of 8 , Jun 30, 2011
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      Ray,

      It appears that you have 2 6 volt batteries in series. That makes 12 volts. 

      Dave

      Sent from my iPad

      On Jun 30, 2011, at 10:52 PM, rayjanine2002 <rayjanine@...> wrote:

       

      I have a three battery system in my 1993 Sabre 362 delivered that way from Sabre back in 1993. My DC system is 12V since that is what my Volt meter is showing on my DC/AC Panel. The house battery bank is composed of two batteries that seem to be hooked up in series which would produce 24V. I have posted some pictures of that setup. How is it possible that my house batteries look like they are in series and yet I have a 12V DC battery system in my boat?

      Thanks,

      Ray
      Second Wind
      1993 Sabre 362

    • sailor11767
      Ray, You have the classic, highly regarded upgrade to battery systems, although by 1993 Sabre may have started doing that stock. That house bank is not the
      Message 2 of 8 , Jul 1, 2011
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        Ray,

        You have the classic, highly regarded upgrade to battery systems, although by 1993 Sabre may have started doing that stock. That house bank is not the traditional 12V battery, but the world-renowned Trojan deep cycle 6-volt. It'd suspect a T-105, a golf-cart battery. The giveaway for the voltage is that a lead-acid cell (the individual component of a battery) is around 2V, and those batteries have 3 cells per battery (the white caps are one per cell). That makes those batteries 6V each. Your start battery probably has 6 cells, maybe 3 each under two caps.

        Note that if you get any water, acid, or other liquid accumulation on top of the batteries, a company called flowsystemsusa.com makes a product called Water Misers that replace those white caps with a water capturing device. Under $30 delivered to do that bank.

        One last comment -- since you posted the pics! Your positive post has 2 big wires, and your negative has 3 big wires. A "normal" battery would have one red wire going to the switch, and one or two negative wires, depending on if it is the second battery in the negative daisy chain. Where do those two big red wires go? If one go direct to another battery, you might have two batteries hard-wired in parallel, perhaps not the wisest arrangement. If that represents a direct connected inverter, I hope there is another switch and breaker in the line.

        OK, one more last comment. If it were me, I'd get that automotive adapter off the automotive post, and move the wires over to the marine screw post under the plastic caps. It gets rid of the lead-to-lead joint on the adapter, and gets the wires to a more secure binding post. On the negative post, you'd end up over the ABYC recommended 3 terminal maximum, but I think it would still be a more robust system.

        Hope this helps.

        Harry

        --- In Sabresailboat@yahoogroups.com, "rayjanine2002" <rayjanine@...> wrote:
        >
        > I have a three battery system in my 1993 Sabre 362 delivered that way from Sabre back in 1993. My DC system is 12V since that is what my Volt meter is showing on my DC/AC Panel. The house battery bank is composed of two batteries that seem to be hooked up in series which would produce 24V. I have posted some pictures of that setup. How is it possible that my house batteries look like they are in series and yet I have a 12V DC battery system in my boat?
        >
        > Thanks,
        >
        > Ray
        > Second Wind
        > 1993 Sabre 362
        >
      • rayjanine2002
        Hi Harry: Thank you for your expert advice. I have an electric winch for raising my mainsail and that is the additional red and black wires going to my
        Message 3 of 8 , Jul 1, 2011
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          Hi Harry:

          Thank you for your expert advice. I have an electric winch for raising my mainsail and that is the additional red and black wires going to my batteries. That circuit does have a large CB between the battery and the winch motor. I am installing an electric windlass and will be adding an additional red and black 1/0 AWG wire to this circuit. There will then be three red cables to the positive post and four black cables to the negative post along with a battery isolator switch and a large circuit breaker. Do you have any recommendation to that additional circuit going to these batteries?

          Kind Regards,

          Ray
        • sailor11767
          Here s a thought -- since you don t raise the anchor and the mainsail a the same time, you could feed the windlass off the breaker for the mainsail. I ll be
          Message 4 of 8 , Jul 1, 2011
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            Here's a thought -- since you don't raise the anchor and the mainsail a the same time, you could feed the windlass off the breaker for the mainsail. I'll be doing an offshoot of this on my boat when I finally get around to installing a washdown pump -- I'll take the heavy duty 40A cable feeding my LectraSan, and right there in the forepeak I'll run a short line to a smaller breaker for the pump. As long as I'm not flushing the head while raising anchor, I'll never trip the main breaker, and I get the benefit of very low voltage drop on that long run, because the cable is sized for a much larger load.

            But, more important is the growth of cables on your battery. ABYC limits you to 3 wires on any terminal, and while your negative currently has 4, one is quite small. Going to 5 is definately over the top. In addition to the ABYC limit, I personally don't like more than 1, 2 tops, on a battery terminal (and neither did my surveyor when I bought my boat -- he dinged me on the pile of wires at my battery). The problem is multi-faceted. The extra wires make managing the batteries difficult (every time you install or remove the battery you can get confused -- I discovered on my delivery home, when I developed a big leak, that I had mis-wired my bilge pump when I took the battery home to charge it -- OOPS!), it puts extra mechanical load on the terminals, it is prone to being a high resistance connection, and perhap most important, it isn't switched.

            I'd take that negative (and the negative from the other battery) and send them both to a terminal block like this:
            https://www.vtewarehouse.com/content/electromech/busbar/html/3point/3point.php
            and then branch out from there.

            If you keep the positive to just the two wires (plus that small one), it doesn't seem to unreasonable. But if you end up with three wires, then you need another terminal block (and it should have a cover).

            I like to know that my battery switch solidly shuts down my battery. Fire, smoke, leaving the boat for the week, etc -- I want to flick that battery switch and know that the battery is isolated. I will soon have a small distribution panel on the battery side of the switch for bilge pump, battery monitor, ect -- but that is all. Nothing big. Your "big breaker" might be able to serve that purpose as well, especially if it feeds both of the loads, and if it is easy to get to. I assume that the breaker is very close to the battery (ABYC wants under 7" if I recall, but realistically it should be no more than 18" or so).

            Expert I'm not. But as an engineer, I suffer from too much curiosity, so I read and think a lot. Hope my thoughts help some!

            Harry

            --- In Sabresailboat@yahoogroups.com, "rayjanine2002" <rayjanine@...> wrote:
            >
            >
            > Hi Harry:
            >
            > Thank you for your expert advice. I have an electric winch for raising my mainsail and that is the additional red and black wires going to my batteries. That circuit does have a large CB between the battery and the winch motor. I am installing an electric windlass and will be adding an additional red and black 1/0 AWG wire to this circuit. There will then be three red cables to the positive post and four black cables to the negative post along with a battery isolator switch and a large circuit breaker. Do you have any recommendation to that additional circuit going to these batteries?
            >
            > Kind Regards,
            >
            > Ray
            >
          • rayjanine2002
            Thanks Harry. What size cable would you recommend from the terminal block to the battery? I am thinking it should be 3/0 AWG so that there is no doubt that
            Message 5 of 8 , Jul 1, 2011
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              Thanks Harry. What size cable would you recommend from the terminal block to the battery? I am thinking it should be 3/0 AWG so that there is no doubt that the cable will take the loads of the other cables hooked to the terminal block and also that there is not a voltage drop because of that cable.

              Kind Regards,

              Ray
            • sailor11767
              Ray, I ll pass on that one. Too many variables to look at it from this distance. A slick calculator that someone pointed out to me (Maybe R.C. told me about
              Message 6 of 8 , Jul 1, 2011
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                Ray,

                I'll pass on that one. Too many variables to look at it from this distance. A slick calculator that someone pointed out to me (Maybe R.C. told me about it?) is here:
                http://boatstuff.awardspace.com/awgcalc.html

                But that jumper cable is hard to calculate, because it is a short leg of a multi-circuit feed. You might want to take this approach:

                * Consider the halyard or windlass to be the "critical" load, and assume only one will be on at any one time.
                * Use the calculator to find the cable to meet the voltage drop for the critical load (I suspect the windlass will be the driving force here)
                * Make the jumper the larger of (one size larger than the critical load) OR ampacity for the sum of all breakers connected. I suspect that 3/0 would well do it. 3/0 can carry over 380 amps safely, which is probably more than you would need, and can carry 100A to a load 25 feet away, which I would think would reach and power your windlass (note that I don't have a windlass, and have no idea what they draw).

                Harry


                --- In Sabresailboat@yahoogroups.com, "rayjanine2002" <rayjanine@...> wrote:
                >
                >
                > Thanks Harry. What size cable would you recommend from the terminal block to the battery? I am thinking it should be 3/0 AWG so that there is no doubt that the cable will take the loads of the other cables hooked to the terminal block and also that there is not a voltage drop because of that cable.
                >
                > Kind Regards,
                >
                > Ray
                >
              • rayjanine2002
                Thanks Harry. Ray
                Message 7 of 8 , Jul 2, 2011
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                  Thanks Harry.

                  Ray
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