Starting Battery won't hold a charge

[Nichole340]

Thank you!
Yes, my Positive and Negative Cables, from the Switch, are directly attached to Battery 1. Then I just used cables from the Battery 1 to connect to Battery 2. Even the diagram I have shows this set up. HOW DID I MISS THIS!
I’ll be redrawing my diagram to show the Negative (Yellow) from the switch going to the Negative of Battery 2, then a cable to Battery 1.
And your both right, I have probably reached the end of life for all the batteries based on this setup.
Time to reconfigure.
Thank you all again!

 

[SailingLoto]

The one battery like has a dead cell. Immediately after charging the battery should read around 13.6 and after 24 hours of rest the charge should be around 12.5 to 12.7. That it declines quickly to 11 v says that one cell is not holding a charge.

If the battery is still under warranty, it could be replaced.

this guy is right. you have a bad cell in your start battery. go buy yourself a proper load tester and test your batteries. I bet the voltage drops like a rock with a load on it.

 

[dlochner]

A switch on the negative side seems a bit unusual. I beleive Beneteau does or has done this, however it seems unusual for a US made boat.

When you get a chance can you diagram the wiring on this circuit?

 

[Maine Sail]

A switch on the negative side seems a bit unusual. I beleive Beneteau does or has done this, however it seems unusual for a US made boat.

When you get a chance can you diagram the wiring on this circuit?

A switch in the negative side does not meet ABYC standards either..

 

[Nichole340]

This is a quick drawing of my wiring diagram. It's how it was wired as this thread began.

 

[dlochner]

This is a quick drawing of my wiring diagram. It's how it was wired as this thread began.View attachment 185811

View attachment 185811

What kind of switch? Is there a negative buss bar somewhere?

 

[FastOlson]

I am puzzled. My OEM 1-2-all switch has only positive cables on the terminals. All the grounds go to a buss bar that I installed some time ago when they were removed from a hard-to-inspect bolt on the bell housing.

Probably just a quibble, but I believe that wiring to the paralleled batteries in site diagram is not quite right either. (?)

Familiar scheme in other ways, tho. I have used a separate "emergency/starting" battery for about 20 years, with a main house bank (for all uses) of a pair of 6 volt GC Trojan flooded batteries, and they normally last 9 years.
We tie to a dock, tho, and our batteries have it pretty easy, living on a shore power charger most of their pampered lives.

 

[LloydB]

"This is a quick drawing of my wiring diagram. It's how it was wired as this thread began."
Make a complete diagram. Missing pieces will make for misunderstanding. It is common knowledge that charging two different batteries or battery sets with the same charger at the same time will cause one of the sets to be eventually damaged, if not both. Sometimes sooner sometimes later.

 

[Davidasailor26]

It is common knowledge that charging two different batteries or battery sets with the same charger at the same time will cause one of the sets to be eventually damaged, if not both. Sometimes sooner sometimes later.

Is it? If they’re all used together as a single bank I agree, but I can’t find any reason why using them in separate banks like the OP proposes is all that bad. The start bank would be the new battery, so the OP could let the alternator charge both banks briefly to recover the starting energy, then switch to the house bank and let that charge independently. Even Maine Sail says that if they’re only combined when charging it’s ok - Got Questions? Ask Them Here.

 

[Nichole340]

When I get back to the boat I will take a photo of the Switch and Wire Positions. It's easier now that the batteries are out of the way. Then a clearer picture will be able show the existing wires.

 

[dlochner]

It is common knowledge that charging two different batteries or battery sets with the same charger at the same time will cause one of the sets to be eventually damaged, if not both.

There are a lot of variables to consider before this "common knowledge" might be considered accurate.

If the batteries are wired correctly 1 charger can charge all of the batteries without damaging them. The batteries must be connected as noted earlier. The OPs batteries are not wired correctly so connecting the charger to just one battery will leave the other one uncharged or poorly charged.

Two batteries connected by an Echo Charger or ACR can be charged from one charger connection, if the connections are done correctly.

Multiple batteries can be charged if the charger has more than one output. Although in a properly wired parallel bank, the bank should be treated as one big battery.

Older ferro-resonant chargers kill batteries regardless of how they are wired.

The battery charger has to have sufficient capacity to properly charge the batteries. Chargers capable of charging multiple batteries only put out the rated capacity in total, not to each battery simultaneously; a 30 amp charger can only put out 30 amps it will distribute the charge as best as it can, it could be 30 amps to one battery or 10 amps each to the three batteries. This could lead to inadequate charging which leads to shortened battery life.

 

[Davidasailor26]

The OPs batteries are not wired correctly so connecting the charger to just one battery will leave the other one uncharged or poorly charged.

I think I agreed with pretty much everything you said except that. Aside from the possible switch on the negative side, and the fact that the yellow and red cables both come off the same house battery, I don’t see any improper wiring. Neither of those issues affect whether the house and start bank can play nice together. The 1-2-B switch isn’t as elegant as an ACR, but if used properly, as the OP described doing, it’s not really incorrect.

 

[LloydB]

Thanks David, the batteries will have been charged as if a single bank but they are not because they have separate capacities and acceptance so the proof that they have not been charged completely is shown by by the need for further charge on one of the banks.

 

[jssailem]

I’ll be reading the marinehowto article for a while myself.

Good decision. Informative and helpful.

You can agree or disagree with the recommendations about the 1/2/Both switch and its use over the years. I believe that @mainesail and others like @Stu Jackson have tried to help boat owners to understand the disadvantages of the "Tried and true" 1/2/Both switch. I am a believer that their idea is better for your boat and the power systems we use. But as always it is you the boat owners choice.

What cannot be disagreed is the need to have a balance to the charging of your batteries. This is battery science. To do this you need to be sure you wire the batteries to get a balanced charge. This means the charge must run equally through all of the batteries being charged.

Look at how battery connections are indicated in your diagram and how they are recommended to get a balanced charge to your batteries. The devil is in the details.

@Nichole340 Battery reported wiring diagram.

MaineSails, wiring diagram.

A simple change to Nichole340's connections... Connect the ground to battery #2 ground to balance out the charge to the bank.

 

[dlochner]

I think I agreed with pretty much everything you said except that. Aside from the possible switch on the negative side, and the fact that the yellow and red cables both come off the same house battery, I don’t see any improper wiring.

I was only referring to the how the 2 batteries were wired to make one house bank, not the rest of the system. Sorry for any confusion.

Thanks David, the batteries will have been charged as if a single bank but they are not because they have separate capacities and acceptance so the proof that they have not been charged completely is shown by by the need for further charge on one of the banks.

In the original post, the OP notes the batteries are Dekks Group 24 Deep Cycle. The manner in which the batteries are currently configured into the house bank does not allow for a balanced discharge or charge. In the current configuration Battery 1 in the house bank will be discharged more deeply than battery 2. As a result the charger will charge based on the condition of battery 1.

If the house bank is rewired as in @jssailem's drawing the batteries will be evenly discharged and will be evenly charged.

The battery that failed is the single start battery. The cause of the failure is not known. It could have been a manufacturing defect, could have been something the prior owner of the batteries did, it could be how the battery was being charged.

A simple solution to the charging issue is to have the alternator charge the house bank directly and the start battery be charge via an ACR. The ACR will prevent the start battery from being overcharged, when the start battery reaching a full charge, the ACR disconnects the battery from the charging source while allowing the house batteries to continue charging.

 

[LloydB]

Thanks dlochner
"There are a lot of variables to consider before this "common knowledge" might be considered accurate."
yep I hesitated when I wrote 'common knowledge' but once thinking about it I considered that it is actually true because most everybody knows that all battery chargers are not the same from cell phone chargers to arc welders just as specific battery sets need different battery chargers.

 

[Nichole340]

jssailem, looking at your correction to my diagram makes all the sense in the world. How and why I connected the house batteries as I show is beyond me. I must have been in a hurry or just not paying attention at the time.

I have never had this type of issue in past years, somewhere I got my wires crossed. Literally.
That correction will be made in the spring.
Also, checking both House Batteries again with the Hydrometer....1 did show slightly less readings than the other. Must have been the second one. But both still take and hold a charge. Winter storage and time will tell though.
I like the idea of an ACR also and will be looking at that option too.
Any recommendations for that (model, size, where to place etc) ?

 

[dlochner]

I like the idea of an ACR also and will be looking at that option too.
Any recommendations for that (model, size, where to place etc) ?

This one:

SI-ACR Automatic Charging Relay - 12/24V DC 120A - Blue Sea Systems

Automatically combines batteries during charging, isolates batteries when discharging and when starting engines.

www.bluesea.com

Location depends on your boat and where it seems to make sense. Keep the cable runs short.

 

[jssailem]

BlueSea makes a good 120AMP 12V solution.

SI-ACR Automatic Charging Relay - 12/24V DC 120A - Blue Sea Systems

Automatically combines batteries during charging, isolates batteries when discharging and when starting engines.

www.bluesea.com

And a clear explanation about the ARC

Automatic Charging Relay (ACR) Explained - Blue Sea Systems

Engineering high quality marine electrical components for safety, reliability and performance

www.bluesea.com

Here is the help provided by MaineSail that I referred to:

Making Sense of Automatic Charging Relays - Marine How To

Making Sense of the ACR WARNING: ACR's are not for use with LiFePO4 Batteries! What is an ACR? An ACR is nothing more than a fully automatic, voltage triggered, BOTH/PARALLEL switch that closes when charging voltage is present and opens

marinehowto.com

 

[Scott T-Bird]

I am probably ignorant to the variety of 1+2+B switches, but the OP diagram doesn't make any sense to me. The only 1+2+B switches that I have ever seen have just 3 posts, not 4. And they certainly don't have the negative cables attached to any of the posts on the switch. What am I missing? Is this a different switch than most of us are familiar with? There are 2 positive posts for the input (2 battery banks) and 1 positive post for the output (house panel and starter). I'd guess that the negative cables are connected to a buss that links to the negative side of loads and the diagram is just confusing. It doesn't help, though. Assuming that the problem that the OP has is that he killed his start battery much quicker than he is killing his house bank, I wouldn't recommend buying and using any new battery until he figures out why he is prematurely killing his batteries, particularly the start battery. But it is pretty clear that relying on a stock alternator for all charging needs, while he is on a mooring, is the reason.