I've just been over the same process myself. After I opened up the breaker panel and looked behind, then followed cable-runs and mapped-out the circuit, I couldn't sleep well.. so I tore the lot out and rebuilt - including the breaker
panels.
On the breaker
panels I installed ELCI/GCFIs in two groups for the AC-panels, relating to both shore-power inlets. I used "restricted off" breakers in a separate DC group for the 3 bilge pumps. See:
https://www.bluesea.com/products/742...ingle_Pole_15A
I liked this, as I wanted to keep a very tidy circuit topology around the battery banks (and under the bunks), and I didn't like the idea that cherry-picked circuits would bypass the breaker-panel and run directly to the batteries. However, the only items that do run direct to the positive and negative "house" rails are the
windlass and an
electric winch (via individual
fuses and a high
current DC switch).
The PO has 8 6V batteries wired in series and parallel to give 12V and 800Ah. However, the batteries were old and sometimes didn't have enough
power left over to start the engine adequately without producing significant drops in system voltage during cranking. I'd have to sit there on calm days waiting for the
solar to put enough power back into the bank to start the engine. Clearly, the PO had possibly taken the bank way below 50%s.o.c. (let alone 80%) on many occasions, and the bank was 7 years old.
With a new bank, not being abused as much, the problem shouldn't occur. However, the thought of a
family member leaving a high-drain device on over-night (or whatever other reason) got me thinking about having a separate battery for the starter.
I reconfigured so that I had 6 6V batteries, 12V 610Ah, for the house bank, and a separate starter battery.
I isolated the starter and house as per ABYC with a "0 1 2 both" switch, but also linked the positive-bus-bars of house and starter with a BlueSea ACR. The negative lead from the ACR (to the neg bus) goes through a switch so I can disable the ACR if I wish.
The good thing is that now the starter automatically gets topped-up whenever the house has a charge source, such as
solar or shore-power, and the house bank automatically gets charge when from the
alternator via the starter bank. However, whenever the
charging source is removed (and the voltage falls back towards rest voltage) the ACR disconnects the link between the two banks.
I know the
concept of a starter battery flies in the face of Nigel Calder's recommendation, but his argument is based upon a "most optimum economic" approach. The idea being that a very large house-bank would
work between than a separate starter and house bank, as a larger overall Ah capacity would mean that you eat into your SOC less each day, so your battery bank cycles less and lasts longer as a result. However, this gives you absolutely no backup incase something happens to your house bank (however unlikely). Anyway, starter batteries are
cheap, so if you're having to replace single battery every few years, it's relatively cheap
insurance IMHO.
Linear Mode
Recent Discussions