Wiring a battery monitor

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David Knauer

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Jun 8, 2004
50
Hunter Legend 40.5 Rock Creek
Hello,
I am considering installing a battery monitor for my boat. I just installed two 135 watt solar panels and would like to closely monitor their output. My boat has a 340 amp house bank consisting of two Decka 170 amp gel batteries. The two batteries are connected in parallel (+ to + and - to - ). I have a three way battery switch which says 1, All, 2, Off. Of the three posts on the back of the switch one leads to battery one and one leads to battery two. The third, which I call a "common" has a wire coming from my inverter/charger and a wire going to the main panel. It has another wire but I am not sure where this leads. Onto this post I wired the + wire from my solar panels. Now I am wondering how to wire the battery monitor? Wouldn't I wire the positive to this "common" post as well?
 
Ron20324

Ron20324

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Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
You really should settle on which monitor you want, then read the instructions. There are many monitors, and "one size does not fit all" as far as wiring goes.
 
D

David Knauer

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Jun 8, 2004
50
Hunter Legend 40.5 Rock Creek
Ron20324 said:
You really should settle on which monitor you want, then read the instructions. There are many monitors, and "one size does not fit all" as far as wiring goes.
Click to expand
I was thinking about the Vectran BMV 600. I am interested in monitoring only the house bank. The starting battery is on a Blue Seas Combiner.
 
willardj

willardj

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Nov 30, 2011
31
MacGregor 25 Savannah
I just ordered one for my boat as well. I went with the Tri-metric 2025. For everything I keep reading it the best investment you can make. Most people even suggest that you get a monitor before you get panels or a generator. As far as hooking it up not hard. They come with good instructions and there's not much to them. Good luck.
 
Ron20324

Ron20324

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Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
David Knauer said:
I was thinking about the Vectran BMV 600. I am interested in monitoring only the house bank. The starting battery is on a Blue Seas Combiner.
Click to expand
I put in the 600 last year. Easy to do. It goes in the negative cableing. For the most part, if it uses or makes electricity, it goes on the load ( I think that what it's labeled?) side of the shut. ONLY the batteries go to the other side of the shunt, and maybe the engine ground as in another thread.
 
walmsleyc

walmsleyc

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Feb 2, 2006
470
Hunter Legend 35 Kingston
This winter I just installed a new charger (Pronautic) and the Victron the 602. I also have the bluesea combiner wired between my house and starting banks.

I'm very happy with everything. I did end up adding a 120v relay that disables the combiner so that the two charging sources don't interfere with each other (use of the shore power charger, which has multiple outputs, disables the combiner).

I find it very informative to know the current draw of the various DC panel items. Watching the battery monitor while each device is switched on/off is very educational.

Chris
 
D

David Knauer

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Jun 8, 2004
50
Hunter Legend 40.5 Rock Creek
Okay, I think i understand that the Victron 600 has the shunt off the negative side of the batteries. I looked over Maine Sail's pictorial explanation of this install but what I am not clear on is the matter of the red wire leading to the positive terminal on the battery. I don't know how to wire this except to the "common" on the battery switch. Can anyone help me with this?
 
M

mitiempo

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Sep 28, 2008
922
Canadian Sailcraft CS27 Victoria B.C.
Here's the install diagram. Ignore the dotted lines - they are for the 602. Victron's shunt requires a positive feed to power its circuitry.
 

Attachments

D

David Knauer

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Jun 8, 2004
50
Hunter Legend 40.5 Rock Creek
So, following the wiring diagram above, what do I input at the Victron setup for my house battery bank? Is it seeing both batteries for a total of 340 Ah, or just one at 170 Ah. I normally keep the battery switch on "all" and not "1" or "2".
 
M

mitiempo

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Sep 28, 2008
922
Canadian Sailcraft CS27 Victoria B.C.
The BMV-600 is designed to monitor the house bank.

Do you have a start battery?

If the 170 AH gels are wired in parallel they should only be wired to one position on the switch. The start battery should be the other position. The way you describe the wiring position 1 and 2 are both using the 2 batteries.

The Victron should monitor both 170 AH gels as one bank of 340 AH.

The switch should not be in the both position once the wiring is changed.
 
Maine Sail

Maine Sail

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Feb 6, 1998
11,702
Canadian Sailcraft 36T Casco Bay, ME
The COMMON post of a battery switch is the post that distributes the power from the batteries. If you select Bank #1 power comes from that battery bank through the COMMON post and onto the DC loads. In many installations the COMMON post is also how the alternator gets its power to the batteries and the switch position determines which bank the loads will be coming from and charging going to..

You don't make any mention of a charge controller for the solar panels. This is a critical piece of gear, especially with GEL cells....

The red wire from the Victron simply connects to the POS post of the bank you are monitoring. The shunt is inserted in the negative wire of the same bank and ALL neg/grounds MUST be on the non-battery side of the shunt or it will not work correctly.

Your description of your bank wiring was confusing. You said + to + and - to - but then said each battery goes to a position on the switch. This does not make sense. Do you have two gels in parallel and a third battery too, or just the two total batteries.
 
Stu Jackson

Stu Jackson

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Feb 26, 2004
23,006
Catalina 34 224 Maple Bay, BC, Canada
D

David Knauer

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Jun 8, 2004
50
Hunter Legend 40.5 Rock Creek
Maine Sail said:
The COMMON post of a battery switch is the post that distributes the power from the batteries. If you select Bank #1 power comes from that battery bank through the COMMON post and onto the DC loads. In many installations the COMMON post is also how the alternator gets its power to the batteries and the switch position determines which bank the loads will be coming from and charging going to..

You don't make any mention of a charge controller for the solar panels. This is a critical piece of gear, especially with GEL cells....

The red wire from the Victron simply connects to the POS post of the bank you are monitoring. The shunt is inserted in the negative wire of the same bank and ALL neg/grounds MUST be on the non-battery side of the shunt or it will not work correctly.

Your description of your bank wiring was confusing. You said + to + and - to - but then said each battery goes to a position on the switch. This does not make sense. Do you have two gels in parallel and a third battery too, or just the two total batteries.
Click to expand
Please excuse me. My confusion comes from my ignorance in this area. I have two gels in parallel which is my "house" bank for a total of 340 Ah. This is the bank that I want to monitor. I also have a third gel battery for a starting battery. I understand that this starting battery is only connected to the house bank through a blue seas combiner and may draw power from the house batteries if it is needed. At other times the starting battery is isolated from the house batteries. My solar panels are connected to the "common" on the battery switch through a Blue Sky SB2512i. I was mentored through this installation by a friend. I installed an "on-off" switch inline before the controller.
Again, please excuse me for the confusion. I hope this clears things up?
 
Stu Jackson

Stu Jackson

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Feb 26, 2004
23,006
Catalina 34 224 Maple Bay, BC, Canada
The battery monitor is only measuring your house bank. If you read the links I provided, you will begin to understand the basic battery wiring, and begin to see why putting anything more on the C post of the switch is unnecessary. All charging sources should go to your house bank, the monitor shunt goes on the house bank negative, and the combiner takes care of the reserve bank.
 
Ron20324

Ron20324

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Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
Seems to me if you program the 600 for 340 ah, when the combiner kicks in, all numbers are out of whack since you're now charging the other battery. I'm not looking at a diagram, but in my head this seem logical, right Mr. Spock? Or not? Maybe move the additional battery's neg to the other side of the shunt?.
 
M

mitiempo

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Sep 28, 2008
922
Canadian Sailcraft CS27 Victoria B.C.
Ron20324 said:
Seems to me if you program the 600 for 340 ah, when the combiner kicks in, all numbers are out of whack since you're now charging the other battery. I'm not looking at a diagram, but in my head this seem logical, right Mr. Spock? Or not? Maybe move the additional battery's neg to the other side of the shunt?.
Click to expand
The BMV-600 only measures the flow from the shunt in the negative of the house bank - it will not measure the start battery. The shunt has to be the first connection after the common negative from the paralleled house batteries. The combiner negative has to be connected on the load side of the shunt.
 
Maine Sail

Maine Sail

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Feb 6, 1998
11,702
Canadian Sailcraft 36T Casco Bay, ME
David Knauer said:
Please excuse me. My confusion comes from my ignorance in this area. I have two gels in parallel which is my "house" bank for a total of 340 Ah. This is the bank that I want to monitor. I also have a third gel battery for a starting battery.
Click to expand
Makes more sense now..



David Knauer said:
I understand that this starting battery is only connected to the house bank through a blue seas combiner and may draw power from the house batteries if it is needed.
Click to expand
It is only connected during "charging" and with solar some current from the start battery may flow into the house bank when the relay combines them. This is why the start battery neg must also be on the load side (non-battery side) of the shunt. If it is not the monitor will eventually become inaccurate.

David Knauer said:
At other times the starting battery is isolated from the house batteries.
Click to expand

This is all determined by voltage. If either bank voltage is in the "connect range" then the relay will be made and the banks in parallel.

David Knauer said:
My solar panels are connected to the "common" on the battery switch through a Blue Sky SB2512i. I was mentored through this installation by a friend. I installed an "on-off" switch inline before the controller.
Click to expand
Ideally your solar panels should be led directly to the house bank not the "C" post of the switch.. With most controllers any On/Off is located after the controller. I would also check with Blue Sky as to where they want to see the On/Off switch. Some controller manufacturers want it between the panel and the controller and some want it between the batteries and controller.


With solar you will also want to make use of the "SI" (starting isolation) feature of the Blue Sea ACR. With the batteries combined when you start the motor, you can overload the capacity of the relay and fry it. This is why Blue Sea came up with the "SI" feature that disconnects the relay during engine starting.

Also PLEASE, PLEASE, PLEASE turn off the "Auto Equalize" function of the Blue Sky controller or you will DESTROY your gel batteries. Ideally the 2512i would not have been a controller I choose for gels. Many gels need a MAX absorption voltage of 14.1V or they can bubble and become ruined. 14.2V is pushing the limits with many brands of gel batteries..

David Knauer said:
Again, please excuse me for the confusion. I hope this clears things up?
Click to expand
Not a problem it just needed some clarification.
 
D

David Knauer

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Jun 8, 2004
50
Hunter Legend 40.5 Rock Creek
Thanks Maine Sail and all others who responded to this link. I wish I knew as much as most of you. I do try to learn from each experience though. I have an email in to blue sky about the position of the on-off switch. My mentor was adamant about locating it before the controller. My boat was hit by lighting 2 years ago and was professionally re-done. Along with this came some additional upgrading of the wiring as well as the blue seas combiner. I know for a fact that a ground wire was added from the alternator going back to the batteries. My batteries are Deka Dominators from East Penn. I choose them because the last gels from East Penn lasted 10 years and were coupled with my Heart Freedom 2000 inverter/charger. Of course the solar is new to the equation. I don't think the "equalize" function is present on the 2512i only on the 2512ix. I don't know if you can follow this link..... http://lib.store.yahoo.net/lib/wind-sun/Manual-BSE-SB2512iX.pdf
Thanks again
 
Stu Jackson

Stu Jackson

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Feb 26, 2004
23,006
Catalina 34 224 Maple Bay, BC, Canada
David Knauer said:
I know for a fact that a ground wire was added from the alternator going back to the batteries.
Click to expand
That is quite odd. Usually the ground wire from the alternator is routed directly to the engine ground.

Given the links I posted earlier, as well as your simple NEED to do so, you should have or make a wiring diagram of your boat. I, too, have a Freedom (mine's a 15).

Here is my rather simple wiring diagram:

http://c34.org/bbs/index.php/topic,4623.msg27335.html#msg27335

None of us were born "electrical boat engineers" but many of us studied a lot and then provided these kinds of links to help others.

Good luck.
 
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