House battery bank charging question

Been following the other battery thread very closely. My present set up is a 4D for gen and 2 8Ds for cat engines. House runs off of these 8Ds. Charger hooked up to all three bats.
Going with a bank of 4 GCs how would I set up the charger to re-charge these bats. Would I be able to also charge from alternator on engines? How would these need to be wired for re-charging? Any help or ideas would be appreciated...thanks.

Not clear if the four GC are in addition to the other three batteries or are replacing one or more of them. Please explain.

If you're going to use the 4 GCs in lieu of the engine batts for house, you can put an ACR between the engine and house batteries. That way, either the engine alt or the charger can charge all batteries. If you set up a 1,2, all switch and 2 ACRs for the house you can split them during charging and both alternators can work independently which will yield somewhat faster charging.

Ken

I also am not clear if you are substituting the GC for the 2 8Ds or adding to them for a separate house bank.

I like the general concept of all charging sources going to the house and then using another system to charge the batteries as Ken mentioned. Blue Seas ACR, Balmar Duo Charger or Xantrex Echo Charger will all work for that. Echo charger is the cheapest and easiest to install I think.

I have Blue Sea ACRs. Very easy. Only problem is on shore power with battery charger on, the ACRs will see the charge voltage and connect the house bank and start batteries. It may confuse your battery charger. I put a switch on the ground wires for the ACRs so when on shore power I turn the switch off which disables the ACRs and each bank will charge independently. The Blue Sea documentation doesn't really explain this so I called them and they confirmed it was the way to go.

Comodave said:

I have Blue Sea ACRs. Very easy. Only problem is on shore power with battery charger on, the ACRs will see the charge voltage and connect the house bank and start batteries. It may confuse your battery charger. I put a switch on the ground wires for the ACRs so when on shore power I turn the switch off which disables the ACRs and each bank will charge independently. The Blue Sea documentation doesn't really explain this so I called them and they confirmed it was the way to go.

Click to expand...

I don't understand what the problem is. If the charger is charging the house bank, the ACR should connect the house and start batteries. I must be missing something. The charger should only be directing charge to the house bank, and the ACR then combines the house and start batteries when a charge voltage is applied.

If you have a smart charger that directs more current to the bank that needs more charging and the ACRs combine the banks into one bank, the needy bank will not get the larger charge current. The charge will be spread evenly throughout the banks and the needy bank may not get fully charged. Simple fix is to open the ground on the ACRs. And the banks will separate. Blue Sea has their brand chargers that can be connected to the ACRs and will do the switching off of the ACRs automatically. Problem is that they don't make a charger larger than 40 amps last time I checked.

Comodave said:

If you have a smart charger that directs more current to the bank that needs more charging and the ACRs combine the banks into one bank, the needy bank will not get the larger charge current. The charge will be spread evenly throughout the banks and the needy bank may not get fully charged. Simple fix is to open the ground on the ACRs. And the banks will separate. Blue Sea has their brand chargers that can be connected to the ACRs and will do the switching off of the ACRs automatically. Problem is that they don't make a charger larger than 40 amps last time I checked.

Click to expand...

Thanks. One reason I like either the Duo Charge or Echo Charge. They don't combine the banks at all but send a small amount of the charge current to the start battery. The house bank gets the bulk of the charging current and the charger never "sees" the starting battery.

Sorry for the confusion. The house bank will be in addition to the 4D and 2-8Ds. I want the 4GCs just for house needs. My question lies in how to connect the charger to the house bank. Could I just attach the charger leads to the Pos and negative post that the cables run from the battery bank to the DC Panel?

Confusion! I'm posting to stay in the loop and learn a bit... I hope!

It depends on the wire size and lenght. It sounds like you may need to get a marine electrican to at least draw up what you need and then if you are confident in your abilities to do the wiring go for it. Hooking up a house bank properly is pretty complex. You have to take into consideration the wire size, fuse requirements, charging and selecting where you are drawing power from just to mention a few of the variables.

OK, my first question is related to the charger. If you have a multi-bank charger, do you still have a free output from the charger that will charge each bank independently?

The charger should connect directly to the battery via an appropriately sized fuse close to the battery. There are plenty of charts you can find on the web to tell you what the appropriate size wire would be (I would size it for a 3% loss) as well as what the appropriate size fuse would be.

I have no idea how to route alternator outputs to the house bank with twins but I would guess that one Alt should go directly to the house as it would with a single.

Deleted

"(I would size it for a 3% loss)"

If speedy charging is desire the least loss the better.
Fat wires are good for multiple amps .

For most folks what counts is the completeness of the charge (100%+full) and that is done with tiny amps over a long time , 3% to 5% is fine, fat wire does not help.

FF said:

"(I would size it for a 3% loss)"

If speedy charging is desire the least loss the better.
Fat wires are good for multiple amps .

For most folks what counts is the completeness of the charge (100%+full) and that is done with tiny amps over a long time , 3% to 5% is fine, fat wire does not help.

Click to expand...

Fred

Your input is always interesting. Thought I'd say the following; for comment.

I keep an "emergency" completely isolated 27 LA starter batt in it's own black single batt box. This batt has come into emergency use twice over the last 9 years, each time it's been needed to replace some other batt. I then replace it with a brand new batt. Constantly attached to the emergency batt is a 1 amp trickle charger that is powered whenever boat's 110 AC breaker is turned on while at dock and/or when gen set is running. Boat's 110 does not usually run because we are not dock sitters, AC is never left on when away from boat, and, gen set runs 1.5 +/- hrs. her day when anchored.

What I want to mention: Multi meter reading on that batt reaches 15.8 while 1 amp charger has been on for an hour or so. And, of course after 110 is off for a day, the reading levels off at 12.7. What amazes me is that the batt gets to 15.8 reading after just a short period [1 hr. +/-] of 1 amp batt charging?? This does not reduce electrolyte count and I've never needed to add distilled water... even after several years.

One of the best ways to do this is also the easiest. https://www.bluesea.com/products/7650/Add-A-Battery_Kit_-_120A Install the batteries follow the directions from Blueseas.. Move the house load feed to the new GCs your done.

Ka_sea_ta said:

One of the best ways to do this is also the easiest. https://www.bluesea.com/products/7650/Add-A-Battery_Kit_-_120A Install the batteries follow the directions from Blueseas.. Move the house load feed to the new GCs your done.

Click to expand...

Think this might do the trick...looks easy enough to install. Thanks for everyone's replies. Will install a new smart charger just for the house bank.

Art said:

What I want to mention: Multi meter reading on that batt reaches 15.8 while 1 amp charger has been on for an hour or so. And, of course after 110 is off for a day, the reading levels off at 12.7. What amazes me is that the batt gets to 15.8 reading after just a short period [1 hr. +/-] of 1 amp batt charging?? This does not reduce electrolyte count and I've never needed to add distilled water... even after several years.

Click to expand...

I'm surprised you haven't cooked that battery. The occasional "On" probably has saved you. Personally I'd put a small smart charger on it (Cetek etc) that will regulate that low demand charge without hitting that 15.8 which seems excessive..

https://www.amazon.com/CTEK-56-864-Automatic-Battery-Charger/dp/B006G14FK8

Heron said:

I'm surprised you haven't cooked that battery. The occasional "On" probably has saved you. Personally I'd put a small smart charger on it (Cetek etc) that will regulate that low demand charge without hitting that 15.8 which seems excessive..

https://www.amazon.com/CTEK-56-864-Automatic-Battery-Charger/dp/B006G14FK8

Click to expand...

That is a good suggestion - Thanks! Next boat visit, I plan to outfit the gen set batt with it's own independent low amp trickle charger... that runs off AC, only when electric panel's breaker is on. I just might purchase two similar chargers to what's on your link - one for each batt. I'd retire the older model motorcycle batt charger I've been using for 9 years on emergency batt.

Our AC breaker is seldom on for more than a few hours at a time with many hours spaced in between... 24 hours has been the longest on time. I have switch that can turn off the 1 Amp trickle charger, which I did do a couple times over the years due to unexpected extended time at dock. As I mentioned in previous post... I've not needed to add distilled water to any one of the emergency batts during 9 yrs., so far using this program. One emergency batt was in the box with trickle charger for over five years. That batt was used to replace the batt in our tow behind O/B Creatliner "Stinger". I was not really low on water even after those five years; as I recall I did top off water in the cells though.