32773Re: DC system in Sabre 362
- Jul 1, 2011Here'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:
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!
--- 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,
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