Winter disconnect for batteries in series

Yes, there is a main switch for each bank. So you're saying that I should not disconnect the cables? My understanding was there could still be some draw that bypasses the switch, like bilge pumps, but maybe that is just for the house bank.
Yes, leave the series linking cable intacked. Many boats have critical loads thats are connected direct to the battery, like the auto bilge, anodes and CO detectors. On smaller/trailer boats, disabling the auto bilge can be a disaster over winter. Ever the the moldy interior when the owner pulls the winter cover off to find the boat has been filling with rain water? Or a wet-slipped boat goes down because of collected rain. Your choice to disconnect the critical loads. However, you are better off the just disconnect the main grounds off the banks. This leaves the seriesed batteries still connected as one large 24V battery.
 
Yes, leave the series linking cable intacked. Many boats have critical loads thats are connected direct to the battery, like the auto bilge, anodes and CO detectors. On smaller/trailer boats, disabling the auto bilge can be a disaster over winter. Ever the the moldy interior when the owner pulls the winter cover off to find the boat has been filling with rain water? Or a wet-slipped boat goes down because of collected rain. Your choice to disconnect the critical loads. However, you are better off the just disconnect the main grounds off the banks. This leaves the seriesed batteries still connected as one large 24V battery.
Ah, but... SB is storing inside so since he'll have no need for those things, disconnecting is fine. :)

Trailer boats laid up for storage wouldn't need those things either since the drain plug should be removed for storage... and, really, removed every time the boat is pulled out.

SB... if your plan is to connect battery chargers every time you visit the boat then, if it was me, I would just leave all batteries connected and turn the battery switch off. When you visit, connect to shore power with an extension cord and 15a to 30a adapter (or 50a, depending on what you have) and let your onboard charger do the work.
 
I wasn't speaking from a car perspective, but agree with the car scenario. Boat's are a little different in that there is not to much to spark too and have a lot more custom wiring then your average car. If car's had battery switches this point would be moot and pulling the positive would make total sense.

Once the positive DC is dead then there is no DC power, pulling the ground does not guarantee that. In most cases turning the battery switch off does the job. The only thing that should be on the battery side of the switch are bilge pumps.

From an engineering standpoint and DC device(s), should anything still be powered some how, pulling the positive is the safest thing to do for an electronic device like a plotter or display etc. Meaning power switches never switch the ground off, they always switch the positive off. Disconnecting the ground first can cause electronics to sustain damage. In most cases boats have multiple ground points and in some cases can find the bonding system enough of a ground to allow dc devices to see low dc voltage. Didn't say in all cases, but in old boats that have had lot's hands in them, wiring is usually an issue.

Turning the battery switch off, does and will prevent arching from changing out a starter. If it does not, that boat has bigger issues then just the starter. I have never removed a ground and only turned off the battery switch when changing a starter, and yes, I have changed many in my life. I also had a mobile marine service for years that turned into solely electronics based over time. So I am speaking form a professional stand point and not a boat owner's one.

I get your point about pulling a cars positive, but we are talking boat's and the two have little in common.
I see where you're coming from, now. Understood.

There's a lot of variables in the boating world - and that's not even taking account the "previous owner" factor you were eluding to... which can sometimes be quite time consuming to fix! ;)

Some boats (smaller ones, primarily) don't have battery switches so that starter lead would be hot. Although that's not the case here so that's more of a tangent and not directly related to this thread.

But for me, my brain is so wired (see what I did there?) to pull that negative cable off the battery first, I just can't convince myself to pull the positive first - in some boats, the batteries are actually quite close to the engine(s). I'm also in the boat business and have always done it that way (including the merc technicians here). But as discussed, this a different scenario than the sensitive electronics you were talking about. I just can't do it, captain! :)

I do appreciate the information you have passed along!
 
I see where you're coming from, now. Understood.

There's a lot of variables in the boating world - and that's not even taking account the "previous owner" factor you were eluding to... which can sometimes be quite time consuming to fix! ;)

Some boats (smaller ones, primarily) don't have battery switches so that starter lead would be hot. Although that's not the case here so that's more of a tangent and not directly related to this thread.

But for me, my brain is so wired (see what I did there?) to pull that negative cable off the battery first, I just can't convince myself to pull the positive first - in some boats, the batteries are actually quite close to the engine(s). I'm also in the boat business and have always done it that way (including the merc technicians here). But as discussed, this a different scenario than the sensitive electronics you were talking about. I just can't do it, captain! :)

I do appreciate the information you have passed along!

One thing to keep in mind, especially if your in the water with a boat plugged into the dock. The DC ground and the AC bonding are one in the same, or should be. They are supposed to be physically tied together. Removing the ground first could cause an issue an possibly get shocked (by AC current) in doing so. Just something to keep in mind and probably should always wear gloves removing the ground from a boat powered by shore power.
 
Ah, but... SB is storing inside so since he'll have no need for those things, disconnecting is fine. :)

Trailer boats laid up for storage wouldn't need those things either since the drain plug should be removed for storage... and, really, removed every time the boat is pulled out.

SB... if your plan is to connect battery chargers every time you visit the boat then, if it was me, I would just leave all batteries connected and turn the battery switch off. When you visit, connect to shore power with an extension cord and 15a to 30a adapter (or 50a, depending on what you have) and let your onboard charger do the work.

Thanks LD. I have 1 50A power cord, and I have 2 battery chargers (12V and 24V) onboard, so I don't know how I'd get an adapter to provide power from a 120V AC outlet.

What I did was rewire the 12V charger so that I can manually install a pigtail 120VAC plug at haul out. This will allow me to run an extension cord to charge the 6 x 12V batteries using the onboard charger whenever I'm down at the boat. This also allows me to keep lights on in the boat for winter projects. I'll top off the engine batteries a couple of times during the winter using a couple of external smart chargers.
 
Something like this would do it. It wouldn't provide enough power to run all of your AC equipment, but should be more than adequate for the chargers and some lights. Although checking the power requirements of each charger would tell us for sure. This will power the boat just like you would from the pedestal at the dock, albeit with less amperage coming in.

https://www.marinco.com/en/p/150SPP/Pigtail-Adapter-15A-125V-Male-To-50A

But, absolutely - if you've got a system that works for you... then keep using it! :)
 
Something like this would do it. It wouldn't provide enough power to run all of your AC equipment, but should be more than adequate for the chargers and some lights. Although checking the power requirements of each charger would tell us for sure. This will power the boat just like you would from the pedestal at the dock, albeit with less amperage coming in.

https://www.marinco.com/en/p/150SPP/Pigtail-Adapter-15A-125V-Male-To-50A

But, absolutely - if you've got a system that works for you... then keep using it! :)

I bought one of those 50A pigtails for my last boat to do the same thing and it did not work. I'm no EE, but I figured it was because it was only powering 1 leg of the 220V, and that leg was not connected to my charger. Or the boat was smart enough to not accept anything but 220V.
 
I bought one of those 50A pigtails for my last boat to do the same thing and it did not work. I'm no EE, but I figured it was because it was only powering 1 leg of the 220V, and that leg was not connected to my charger. Or the boat was smart enough to not accept anything but 220V.
You don't have to be an EE to figure that out... you just shouldn't be a space cadet and totally space on that little fact like me ;)

Now... you could... swap the breakers for the chargers to the other line and bring two same-sized breakers back over the first line... but I think the way you're currently doing it is "just fine"!
 

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