Two questions here:
there is a batt selector that can be set to 1, 2, Both and Off. it is my understanding "Both" will connect the positives of the two banks. I haven't managed to see the exact wiring at the selector, it's located at the lower corner of helm station with difficult access
Then my suggestion stands if you charge both banks with the same charger(s) and have only one shunt, one monitor. You select 1 or 2 or both flow will be measured.
Yes, I think you have a good understanding of how it’s wired. In addition to routing power to the house loads, the battery selector switch also routes it to the starter.
Functional, maybe. Practical, no. It’s not really a good idea to use one shunt for multiple banks. The amp hour counting depends on measuring in and out, and some are “smart” and learn over time.
I intend to leave the rewiring for later on, after the ongoing projects
Missed seeing this post earlier, sorry.
Thanks for reviewing the lengthy thread and understanding those boring questions.OK, I went back through the thread, to sort of "review the bidding"... and I see this is the one that started with a worry about potential overcharging... and then morphed to something about monitoring something somewhere on or around post #81...
But there's the post describing loads on each main bank -- inverter on each, MSD on one, thrusters, fuel pumps -- and I'd imagine there are probably some lighting circuits (nav, anchor, deck lighting, interior lighting), nav electronics. One inverter feed a fridge, the other ....?? Maybe AC outlets for things like laptops, toasters, coffee makers, icemaker, microwave/convection oven, tuner/stereo amp, TV? IOW, the loads are separated...
And near as I can guess, since the main loads are separate, the "two banks" thing is NOT to swap between one and the other at anchor. (In which case, all loads would transfer? Some guessing, there.... ) Instead, I'd guess that architecture was specifically to spread the DC loads (and inverter AC loads), and maybe the only reason for a combiner switch is if the user over-achieved drawing down one bank or the other... so the switch can act as a temporary safety net... until the real fix (recharging) can happen.
If that's anywhere close at all, I doubt I'd spend much time worrying about changing battery architecture. Instead, I'd just (over time) beef up each battery bank to the extent necessary/possible (that extra battery box for each might be applicable), put a monitor on each bank, call it good, and move on to a real problem.
3x G31s on each bank is probably ~300 Ah nominal capacity, ~600 Ah total. Adding a fourth to each bank would make it ~400 Ah each bank, ~800 Ah total. What's not to like? The cost of a second monitor is basically squat, in the grans scheme of things.
(Some of this is guided by experience with battery architecture of our previous two boats and this current boat. All had/have two main banks; each starting an engine and each servicing about half of the DC house loads. Only one had a 1-2-All switch, and it was the boat with only 3x batteries total, 1x on one bank, 2x on the other (fridge) bank, not much room for additional batteries. The DC panels were/are separated for basic load management, not for swapping out which bank happens to be servicing a whole house at any given time. No way to do that on the last two boats without 1-2-All switches. Instead, that's what starting a generator solves.)
Bottom (sorta) line: the current architecture is workable, and a (completely discretionary) monitor on each bank could be a good thing, physically rewiring the two banks into one larger bank would buy not a lot -- at significant expense expressed in either time, money, or both.
It is, of course, highly possible that I don't know what I don't know relative to OPs situation, goals, etc.
-Chris
Thanks.
Yes, there two dc panels in the bilge each directly connected to a bank. The main dc panel is at the lower helm. The batt selector is at lower right corner in the photo
Sorry this post might be a little fragmented, I wrote some of it last night after a cocktail or two…OK, I went back through the thread, to sort of "review the bidding"... and I see this is the one that started with a worry about potential overcharging... and then morphed to something about monitoring something somewhere on or around post #81...
But there's the post describing loads on each main bank -- inverter on each, MSD on one, thrusters, fuel pumps -- and I'd imagine there are probably some lighting circuits (nav, anchor, deck lighting, interior lighting), nav electronics. One inverter feed a fridge, the other ....?? Maybe AC outlets for things like laptops, toasters, coffee makers, icemaker, microwave/convection oven, tuner/stereo amp, TV? IOW, the loads are separated...
And near as I can guess, since the main loads are separate, the "two banks" thing is NOT to swap between one and the other at anchor. (In which case, all loads would transfer? Some guessing, there.... ) Instead, I'd guess that architecture was specifically to spread the DC loads (and inverter AC loads), and maybe the only reason for a combiner switch is if the user over-achieved drawing down one bank or the other... so the switch can act as a temporary safety net... until the real fix (recharging) can happen.
If that's anywhere close at all, I doubt I'd spend much time worrying about changing battery architecture. Instead, I'd just (over time) beef up each battery bank to the extent necessary/possible (that extra battery box for each might be applicable), put a monitor on each bank, call it good, and move on to a real problem.
3x G31s on each bank is probably ~300 Ah nominal capacity, ~600 Ah total. Adding a fourth to each bank would make it ~400 Ah each bank, ~800 Ah total. What's not to like? The cost of a second monitor is basically squat, in the grans scheme of things.
(Some of this is guided by experience with battery architecture of our previous two boats and this current boat. All had/have two main banks; each starting an engine and each servicing about half of the DC house loads. Only one had a 1-2-All switch, and it was the boat with only 3x batteries total, 1x on one bank, 2x on the other (fridge) bank, not much room for additional batteries. The DC panels were/are separated for basic load management, not for swapping out which bank happens to be servicing a whole house at any given time. No way to do that on the last two boats without 1-2-All switches. Instead, that's what starting a generator solves.)
Bottom (sorta) line: the current architecture is workable, and a (completely discretionary) monitor on each bank could be a good thing, physically rewiring the two banks into one larger bank would buy not a lot -- at significant expense expressed in either time, money, or both.
It is, of course, highly possible that I don't know what I don't know relative to OPs situation, goals, etc.
-Chris
That’s the correct wiring. You will only get a volt reading from the aux input. It will be completely separated from the meters amp hour/soc measurement. Still, it’s a good thing to have. That battery just site there with no loads on it, so a fairly accurate state of charge can be had by looking at the resting voltage. Resting voltage is after the battery is unused for 24 hours.
Thanks for the confirmation.
anther question, is it necessary to open the dc circuit before adding a ring terminal to the dc panel? if so, does this mean to disconnect the neg cable that is wired from the buss bar shown here to the battery bank?
i think both sides of the main panel is run by either bank or both. bilge pump breaker is on the left side, sump pump (forward bilge pump) is on the right side, with the batt selector on 1, sump pump is still powered. with the batt selector to Off, both pumps are offline.
Thanks for the link. I watched it before buying the monitor.
It’s always best practice to de-energize the circuit before working on it.
Can a use 10awg? This is what I have now.
I was able to enlarge the hole using a 3/8" drill. I had to clamp the cable to a portable work bench, drill it in consecutive pulses.
