5 batteries one red.

[Hoohaa]

Originally Posted by sailah

Yes the engine is also grounded to the bus bar. In the schematic, the engine starter is shown with a ground wire back to neg bus bar. In reality, engine starters do not have a neg stud on them usually so your ground is some tapped hole on the engine block. Mine had this already, but the lug was corroded so I replaced it entirely as the cable run was pretty short to the neg bus bar.

Steps that I took to upgrade where I was previously:

-DC panel had a cable that ran to the engine block. Which was then grounded to batteries. I ran a fresh cable from panel directly to bus bar and did the same for engine block.
-Alternator had a short jumper cable from ground post to engine block. I redid this to bring the ground from alternator directly to bus bar. The concept of this is to reduce voltage drop as much as possible.
-All existing cable was cut at the lug and inspected. If shiny and bright, I recrimped a new lug with heat shrink. If suspect, I cut back until it was too short and replaced it or I found shiny (by shiny I mean good tinned not bare copper)
-I debated about the high amperage loads like the windlass going to the starter vs house. In the end, I decided to follow schematic and run ALL loads to house except the engine starter. All charging loads also go to the house.
-This way I could use the Balmar battery monitor on the house and know exactly what the loads were. Starting an engine requires minimal energy for 2 secs so I never even worry about the starter. I did run the extra voltage sense wires from the battery monitor to the engine start battery so I can read the voltage on the starter bank.
-I was extremely limited in space where I wanted to do these battery improvements so I acquired all my components and made a plywood mockup to fit. I then spent a fair amount of time laying everything out and securing to plywood, predoing the short cable runs on my desk. Then I installed the plywood after painting and just made the connections.
-I bought many of my components from industrial wiring suppliers as they are substantially less expensive vs the marine store. Buy 3x more than you need.
-I used industrial fuse holders and made my own copper bars as I was limited on space. Labeled everything with a cheap Brother label maker and then used clear heat shrink over the regular adhesive shrink to make sure I knew what all cables are.
-So far it's worked great and really cleaned up my wiring. I know where everything is. Was a lot of work and investment in tools (like the lug crimper) but I feel was worth it. Probably more than you wanted to do vs just replacing batteries but I always try to find excuses to improve and buy new tools!!

Fantastic post.
Thanks, allot of great info here and it's really giving some great ideas.

[Phil_Fr]

The indicator is there to indicate the acid level only.

If you can get very carefuly the vent cap covers off, step 1 is to check the fluid level and top off with ONLY distilled water..... Check ALL elements of each battery, and perform this inspection every 6 month is better for battery life.

Wears gloves (minimum), sulfuric acid is corrosive...
And don't trust any drop even it doesn't foam ou stay inert, sulfuric acid is very dangerous...

[skenn_ie]

I thought they were fluid level indicators too.

[LargeMarge]

Some banks with multiple batteries hook the house to the first battery, connect the second battery to that, the third to the second, etcetera.
Unfortunately, that loop works the end batteries harder than the center batteries.

A better system might be to gang all the positive terminals to a common off-bank post, then draw the house from that one post.
Negative terminals are similarly ganged to an off-bank post.
Drawing from the off-bank post works each battery equally.

Let us know your results.

[skenn_ie]

3 options for connecting parallel batteries. Best: HEAVY buss bars running alont the stack, then connect to the centre of that for feed and charging. Good: Wires of the same gauge and length going from battery to main terminal. Mediocre: Connect positive to one end of the stack, and negative to the other end.

[hpeer]

Originally Posted by Hoohaa

I have a bank of 5 * 12v batteries. They are around 3 years old.
Bought and installed at the same time.
Sit at around 13.7v.
I have been very happy with them.

While replacing my sink I was able to get a good look at 3 of them and noticed that the middle of the 3 was showing red in the little window.
I checked all of the voltages and they where all the same.
Do I need to disconnect the battery to test it properly?
Is it likely that the indicator window is malfunctioning?
Can it damage the other batteries in the bank?
Is it common for one battery to malfunction when wired as part of a bank like this?
Thanks. Jeff
Attachment 213261

OK, I’m a dope.

1-I can’t see the little window

2-The battery only the left is different than the other two. So I’m guessing that is your start battery? It has different connectors and it has a lift handle.

OR my eyes are worse than I though?

So maybe you have 2 banks. A start battery and then 4 each 12v batteries in parallel?

If going with GC-2 batteries they do need water off and on. If it’s a real pain to get to the batteries then you might want something different.

[Hoohaa]

Originally Posted by hpeer

OK, I’m a dope.

1-I can’t see the little window

2-The battery only the left is different than the other two. So I’m guessing that is your start battery? It has different connectors and it has a lift handle.

OR my eyes are worse than I though?

So maybe you have 2 banks. A start battery and then 4 each 12v batteries in parallel?

If going with GC-2 batteries they do need water off and on. If it’s a real pain to get to the batteries then you might want something different.

The pictures show batteries 123. 4 & 5 are elsewhere. Room is tight.
Hense the current interest in a phisically smaller bank

[hpeer]

I get that 4&5 are elsewhere.

I was just commenting that not all 3 batteries are identical. The one on the left is different.

I’m guessing the one on h th e left is wired for start and the other 4 are identical and make up one house bank.

[Hoohaa]

Originally Posted by hpeer

I get that 4&5 are elsewhere.

I was just commenting that not all 3 batteries are identical. The one on the left is different.

I’m guessing the one on h th e left is wired for start and the other 4 are identical and make up one house bank.

I have 6 batteries on board. 5 make up the bank and 6 is the starter.
You are correct. There is one odd battery. Added not long after the others.
The other 4 in the bank are identical. Specs should be the same across the board.

[fschaefer4]

@sailah
I'm trying to google Maine Sails but for the life of me I can't find their website. I feel dumb asking, but can you post their website?

[sailah]

Originally Posted by fschaefer4

@sailah
I'm trying to google Maine Sails but for the life of me I can't find their website. I feel dumb asking, but can you post their website?

https://marinehowto.com/

And the article that got me started with explanation of ACRs and schematic:

https://marinehowto.com/automatic-charging-relays/

[fschaefer4]

@Sailah- thanks.

I love that site. I've come across it a few times and always seem to forget to bookmark it. I got it now. So much good info.

[n5ama]

Originally Posted by Pete7

Certainly worth lifting them out and giving them a good clean including the terminals.

Pete

Pete has a good suggestion in cleaning the battery especially if the boat was used in salt air.

A residue of battery acid and or salt deposit from the air will provide a low resistance path between the positive and negative terminals. You can disconnect the terminals from a battery with this crud on the top of the case, put a voltmeter across the battery and just about watch the voltage drop.

The acid component of this is only a problem with lead acid batteries but the salt deposit can be a factor without the acid.

A clean water rinse does wonders to stop the discharge. This background discharge is 24/7 and especially noticeable if you don’t keep a trickle charge on it. The trickle charge has to work a little harder to overcome this discharge.

[Hoohaa]

Update.
I have researched lithium and because of the costs, I will probably install them on my next boat.
I have decided to go down the 6 volt path and yesterday,picked up four 6 volt 230ah batteries.
I might add 2 more if I can fit them under the nav seat.
I will post more on the install as I go.

[skenn_ie]

Do install a charge balancer and a GOOD charge controller on your engine alternator/s.