Question about Battery Combiner

reworb

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Apr 22, 2011
234
Beneteau 311 Ft Myers Beach
I have a Beneteau which came from the factory with those battery disconnect switches one for each bank. There are two banks, one bank is a single battery and is connected solely for engine start. The other is a 2 battery bank connected to the panel for the house loads. There is a Xantrac 3 bank charger connected to the batteries, each bank is connected independently. There is also a Blue Sea combiner. I am not the original owner of the boat and the previous owner messed around with the wiring.

I'm not sure if the the charger is working so I unplugged the boat from the AC and I took the cables off the house house batteries and charged them separably with my portable charger. When they were charged I reconnected them. I then hooked up the the charger to the engine start battery and left all the cables connected. While the charger was running I checked the digital voltage meter on the panel, it showed 14.2 volts for the engine start as expected. It also showed 14.2 volts for the house bank. That indicates to me that the house bank was also being charged.

My question is should the combiner combine the banks when they are being charged from a multi bank charger or only when being charged from the alternator?
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
My question is should the combiner combine the banks when they are being charged from a multi bank charger or only when being charged from the alternator?
Yes that is what a voltage sensitive relay does. With a VSR/ACR you no longer need to use all the outputs from the charger and can simply run all charge sources to the house bank and let the ACR do the rest..
 

reworb

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Apr 22, 2011
234
Beneteau 311 Ft Myers Beach
Thank You I was hoping you would answer. Will it damage the batteries or the charger if it remains hooked up as it is?
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
Thank You I was hoping you would answer. Will it damage the batteries or the charger if it remains hooked up as it is?
No it won't hurt it at all... The charger is really only one charger, with one power supply, and one voltage regulator with two or three diode or fet isolated outputs (check valves) to simply prevent back drain when the charger is off. The idea of a three-bank charger is really quite misleading.
 

KZW

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May 17, 2014
831
Catalina 310 #307 Bluewater Bay, FL
Maine Sail,

I have four 6VDC golf cart batteries with two each connected in series for two 12 VDC banks. Charging is via a ProMariner 63120 ProNauticP Series 1220P Charger. It also is a "three bank" charger. I have two of them connected, one to each battery bank. Should I just run a jumper so all three outputs are connected together?

Cheers!
 
Mar 20, 2012
3,983
Cal 34-III, MacGregor 25 Salem, Oregon
Maine Sail,

I have four 6VDC golf cart batteries with two each connected in series for two 12 VDC banks. Charging is via a ProMariner 63120 ProNauticP Series 1220P Charger. It also is a "three bank" charger. I have two of them connected, one to each battery bank. Should I just run a jumper so all three outputs are connected together?

Cheers!
Im not Maine Sail, but until he checks in with you, I'll help you out and say yes, that would be better and cleaner to have them all go to the same terminal, if you are using an acr of some type.... if you dont have some way to combine the batteries other than a master switch, it will work only as dependable as your mind does in remembering to flip the switch.... this is the advantage of an AUTOMATIC combiner. it does it automatically when required and puts all the amps where they are needed, rather than trickling them in at various points.

but im wondering why you have two banks of 2 GC batteries each.... are you currently using a combiner relay, or just depending on the different feeds from the charger?
one bank of 4 GC batteries can offer over double the house power you currently have, plus even cycling of all the batteries, and can be a lot easier on the batteries, which equates to a longer life.... and if you need a backup battery in case you run them down, install a much cheaper automotive battery as a back up starting battery....connect it simply with a combiner relay. it will last a long time.
 
Last edited:

KZW

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May 17, 2014
831
Catalina 310 #307 Bluewater Bay, FL
They are operated as one bank. The battery selector switch is always on ALL. They are wired that way because the OEM installation was two 4D batteries and that is the way they are wired. The eventual plan is to put them together into a single bank and add a starting battery. However, that will take more shuffling around to get things to fit and there are other things that are demanding attention.
Work keeps interfering with my boat habit.

Any recommendations on an automatic combiner?
 
Mar 20, 2012
3,983
Cal 34-III, MacGregor 25 Salem, Oregon
Work keeps interfering with my boat habit.

Any recommendations on an automatic combiner?
Darn work... Ive been looking for a cure for that problem here too....

then it seems that you already know the advantages of one large bank of quality batteries. over 2 smaller ones,

I have the bluesea ACR, and like it, but I believe yandina has one a bit cheaper that it has been recommended but im not familier with it (yandina products do have a good reputation).... Maine Sail has another brand that he recommends also, but I cant recall it...

if you install one now, and connect all the charge leads to the same post, it will give immediate benefits, and you will then have everything needed when it comes time to get all the GC batteries into the same bank. it will only be a matter of rerouting the wires.
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
They are operated as one bank. The battery selector switch is always on ALL.

Any recommendations on an automatic combiner?
If you are operating the banks the way you describe, batt switch always on ALL, a combiner is redundant. When you add the start battery the Blue Sea 7610 is a great unit. They are super reliable, so reliable I have never seen one fail.
 

obdoor

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Jul 13, 2015
39
Pearson 33 NC
I'm confused. I'm planning to add a third battery. I have only two batteries on a one/two/all/off switch. I have a three bank charger with two banks currently attached. I wanted to isolate the new starter battery on a new switch and attach it to the third bank of the charger. Are you recommending that I put an ACR between the two house batteries for optimum efficiency in charging my house batteries ?
 
Feb 26, 2004
22,760
Catalina 34 224 Maple Bay, BC, Canada
Are you recommending that I put an ACR between the two house batteries for optimum efficiency in charging my house batteries ?
No. Once you parallel two batteries (12V) you make them into what is called a BANK. So: you have two batteries in the HOUSE bank, and one battery in the reserve BANK.

What the combiner or ACR does is combine the two different BANKS when charging sources are present, and then automatically disconnect them.

Don't understand the additional switch. Keep your existing 1-2-B switch.

Basic Battery Wiring Diagrams This is a very good basic primer for boat system wiring: http://c34.org/bbs/index.php/topic,6604.0.html

This is another very good basic primer for boat system wiring: The 1-2-B Switch by Maine Sail (brings together a lot of what this subject is all about)
http://forums.catalina.sailboatowners.com/showthread.php?t=137615
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
Maine Sail,

I have four 6VDC golf cart batteries with two each connected in series for two 12 VDC banks. Charging is via a ProMariner 63120 ProNauticP Series 1220P Charger. It also is a "three bank" charger. I have two of them connected, one to each battery bank. Should I just run a jumper so all three outputs are connected together?

Cheers!
Charlie Sterling (Sterling Power) suggest doing this as it balances the load output across three FET's, as opposed to just one, making all three work less hard than just one. This means less heat for each output and less heat means longer life.. ProMariner I don't believe has an opinion. The chargers were jointly designed and built.
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
I'm confused. I'm planning to add a third battery. I have only two batteries on a one/two/all/off switch. I have a three bank charger with two banks currently attached. I wanted to isolate the new starter battery on a new switch and attach it to the third bank of the charger. Are you recommending that I put an ACR between the two house batteries for optimum efficiency in charging my house batteries ?
Your two house batteries should be ONE battery bank contiguously wired. This is Bank #1/HOUSE and as a charger goes it is one battery not two.

Bank #2 is your start battery and can be charged via an ACR. Without knowing which charger you have it is difficult to say how it should be wired as some of them are really not designed for cruising boats and can double as bass boat chargers doing both 12V or 24V depending upon how you wire them. If it is a standard 12V charger with three output terminals then "generally" you should wire the charger to the house bank if using an ACR or other charge management device. However some chargers are built very cheaply and can't drive full current to just one terminal and they may "split" the outputs as say 5A and 5A vs. 10A for the whole charger.

More information is required because there are a lot of chargers out there not really designed nor well suited to deeply cycled banks......
 

obdoor

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Jul 13, 2015
39
Pearson 33 NC
The battery charger I have is a NOCO Genius 3rd Gen 30 amp 3 bank smart waterproof battery charger. I have yet to install the third battery. When I do I'd like to dedicate it as a starter battery. I have spot where I feel I can place it without a major modification. I had purchased a blue seas 4 position selector switch to use as a emergency switch for my starter battery. If I am to understand you guys you recommend that I wire the two house batteries in series and use an ACR between the new combined house bank and and the starter battery bank. Also, use my existing 1/2/both/off switch without using the newly purchased switch.
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
The battery charger I have is a NOCO Genius 3rd Gen 30 amp 3 bank smart waterproof battery charger. I have yet to install the third battery. When I do I'd like to dedicate it as a starter battery. I have spot where I feel I can place it without a major modification. I had purchased a blue seas 4 position selector switch to use as a emergency switch for my starter battery. If I am to understand you guys you recommend that I wire the two house batteries in series and use an ACR between the new combined house bank and and the starter battery bank. Also, use my existing 1/2/both/off switch without using the newly purchased switch.
Not series if they are 12V batteries. They would be wired in parallel. All three outputs of the Noco could be wired together to feed the house bank then the ACR would simply charge the start bank. You do not need an extra switch...

The Noco's are an interesting charger in that they do have three outputs but they lack any programability (because they are waterproof) so the batteries really need to fall into the 14.4V range in order to work well with them. Batteries vary in absorption & float voltage settings and a single voltage charger is not really the best choice.

The Noco's are not well suited to GEL (14.1V), obviously, but they can work for most AGM and flooded batteries, though they are less than ideal. Every maker of AGM and GEL batteries want to see temp compensated charging and the Noco can;'t do this. Trojan and other deep cycle batteries prefer 14.7V - 14.8V and the Noco can't do this..

These water proof chargers don't have temp compensation, because that would make them not very waterproof, and don't do a true float. They cycle in and out of absorption and key back on at somewhere around 12.8V and go back to 14.4V, then eventually shut off again, drop to 12.8V and repeat the process. This is not float charging.

The Noco is also not the best choice for a boat that runs dock side DC loads because the loads can keep it in absorption far longer than the batteries should be in absorption. They are reasonable enough for charging unloaded batteries.

Keep in mind you don't really get a 30A charger you get a 10A, 10A & 10A charger... If we consider that the start battery is taking 0.2A the other 9.8A of that output simply goes to waste.

A dedicated 30A distributed by demand charger (Sterling ProCharge Ultra or Promariner ProNautic P are good examples) would give 29.8A to house and the 0.2A to the start.

By running all three Noco outputs direct to the house bank you can replicate a legit deep cycle battery charger and the house can actually see all 30A when it needs it. The ACR will parallel with the start bank and keep it charged..
 
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obdoor

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Jul 13, 2015
39
Pearson 33 NC
Thanks for your comprehensive explanation. I'm a big fan of your blog and appreciate your involvement with sailboatowners.com. When I first purchased my Pearson I spent a fair amount of time reading compass marine and even contributed with a donation. All your efforts are greatly appreciated.
 

Dan_Y

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Oct 13, 2008
514
Hunter 36 Hampton
This is a great thread an made me realize something about ACR versus echo charger.
The choice of bank combining technology (ACR or echo charger) seems to depend on the battery technology being combined and how you configure your charger outputs. If you have a flooded open lead acid house bank and start/aux bank, running the charger output to only the house bank will potentially cause under charging of the start bank if an echo charger is used. Both the Sterling and Pronautic P will charge flooded open lead acid batteries at 14.8 or 14.7v during "conditioning" or "high" charge. But the xantrex echo charger, for example, limits it's output to 14.4v if the input rises above 14.4v. That would make charging less effective and equalization at 15.5v ineffective through an echo charger.

So it seems the BSS 7610 with its higher voltage limit of 16v is the way to combine these battery types. Plus running only a single charger wire with fuse cuts down on wiring cost and helps pay for the ACR. Once the ACR is combined, it looks like it will stay that way even when the chargers drop into power save mode and lets the battery voltage drop to 12.8. The echo charger seems to be a good configuration for alternator charging while under way, but the start bank requires its own charger output. I looked at all four spec sheets as I'm studying how to reconfigure my charging system. But what did I overlook?