Starting Battery won't hold a charge

[Nichole340]

I have a 3 battery setup on my 340. 3 Deka Deep Cycle Group 24. I use 1 as a Starting Battery and the other 2 as my House Bank. I had a friend selling his boat and he had these on his boat. They were all purchased the same day (May 2018) and were 3 months old and used only to start his engine, as he was not using the boat anymore.
The one I use as a starting battery worked fine right up to yesterday (10/6/20), it will charge up to 12.50 V but will not hold, it drops to 11.05 V and will not start the boat. It has a Hydrometer Reading of 1.150 which is telling me to recharge it.
I want the 3 battery setup but, will adding a new battery (same one) effect the the other two? Will they try to drain the new b attery if switch is left on Both?
The batteries are to new to replace the whole system to keep everything the same age and size. And I really want the 3 battery setup I have. Just feel more confident with that amount.
How would you handle adding a third new battery?

 

[jssailem]

There are missing facts to your question.
How are the batteries wired?
How are the three batteries charged?
Do you have separate control of the starter battery from the house batteries?
How are you charging the batteries?
Do you use an ARC to charge the Starter Battery?
Just because the battereis are new in years, does not mean that there care has not caused them to age.

 

[Don S/V ILLusion]

depends on how you charge them, i.e., thru an echo charger, isolator, etc... more info needed

 

[dlochner]

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.

 

[Scott T-Bird]

I would first look up Musings with Maine Sail in this website of forums and read his postings that reference battery charging and selector switches. I would first study the various methods of charging via alternator and/or battery charger to understand how batteries are charged. I would then decide how I want to charge my batteries and how I want to use the selector switch. I would learn all that before buying new batteries and installing them. It seems that you are not charging the battery that you use for starting. Perhaps it is because it is not connected properly to an external charging source and perhaps it is not being charged by the alternator (while your house bank is) if you don't have an ACR (or even if you do and it is not being used properly) or you are not selecting the start battery for charging. We don't know your habits. I think that basically you need an ACR and/or an external battery charger that charges multiple battery banks simultaneously. We don't know how you use your selector switch (your habits). If you want a separate start battery, as opposed to starting with your house bank, you need to make sure your charging system is charging your start battery. If you are relying completely on the alternator to charge your batteries, you are probably chronically undercharging your batts, leading to their demise. There are way too many variables for anybody to zero in on your charging problems without more information.

 

[Nichole340]

It's a basic system. Two are wired Positive to Positive, Negative to Negative, then to one side to a standard 1-2- Both Switch. The other is to the other side side of the switch.
Standard to a 2000 340 setup.
The only way I can separate the batteries is by using the 1-2-Both Switch, when starting the boat, I switch to Number 2. Then once started and running I switch to Both so I can charge while underway. A lot of work compared to others setups, but it works.
I charge using the Alternator with the engine during the season. And have always had this 3 Battery set up this way. And it works fine.
Using the Protech 4 100 Amp Charger is not an issue, as I am on a mooring all season. With only occasionally stops at a dock for extended times to use the charger. Which also works fine.
I only noticed this problem when I began to winterize the boat and found the engine would not start with the one battery. At home, on my charger, was when I found the drop in voltage and Hydrometer readings.
All cells measure the same 1.150 Hydrometer reading, so it's hard to say about a dead cell. Looks like just bad battery to me.
I'm sure I can get the battery replaced or prorated at the least.
But the question is adding a new battery to, what will now be 2 - 3 year old batteries. Will next year bring a whole new host of battery issues with the two wanting to draw from the the new one, if the switch is set on Both?
Others must have been faced with this same type issue and not wanting to replace 3 batteries because of one bad one.

 

[JamesG161]

Standard Hunter set up.

Start Battery is separated from the House Batteries.

You can not and should not cross them.

Start Battery is charged using the Engine Alternator.

Normally Houses Batteries are charged using your on board battery charger.
Jim...

 

[Scott T-Bird]

It's a basic system. Two are wired Positive to Positive, Negative to Negative, then to one side to a standard 1-2- Both Switch. The other is to the other side side of the switch.
Standard to a 2000 340 setup.
The only way I can separate the batteries is by using the 1-2-Both Switch, when starting the boat, I switch to Number 2. Then once started and running I switch to Both so I can charge while underway. A lot of work compared to others setups, but it works.
I charge using the Alternator with the engine during the season. And have always had this 3 Battery set up this way. And it works fine.
Using the Protech 4 100 Amp Charger is not an issue, as I am on a mooring all season. With only occasionally stops at a dock for extended times to use the charger. Which also works fine.
I only noticed this problem when I began to winterize the boat and found the engine would not start with the one battery. At home, on my charger, was when I found the drop in voltage and Hydrometer readings.
All cells measure the same 1.150 Hydrometer reading, so it's hard to say about a dead cell. Looks like just bad battery to me.
I'm sure I can get the battery replaced or prorated at the least.
But the question is adding a new battery to, what will now be 2 - 3 year old batteries. Will next year bring a whole new host of battery issues with the two wanting to draw from the the new one, if the switch is set on Both?
Others must have been faced with this same type issue and not wanting to replace 3 batteries because of one bad one.

If you are on a mooring and relying on the alternator, my bet is that your batts are chronically undercharged. Your alternator doesn't keep up with the charging demand if you only have the engine on for short periods. It might be trying to keep up with charging the house bank and the start batt isn't getting any charge. You need a solar charger if you can't connect to dockside power frequently. That's just my thoughts and opinion. The previous owner of my boat used solar while he kept the boat on a mooring. He also installed a high output alternator to provide a boosted output during his short trips out to sailing grounds.

 

[Don S/V ILLusion]

But the question is adding a new battery to, what will now be 2 - 3 year old batteries. Will next year bring a whole new host of battery issues with the two wanting to draw from the the new one, if the switch is set on Both?
Others must have been faced with this same type issue and not wanting to replace 3 batteries because of one bad one.

Not what you want to her but the answer is .... it depends.

It depends on how different the internal resistance is among the old and new batteries but you probably can’t tell so think of it this way - as long as you don’t consistently run the old/new combined on the “both” setting for a prolonged time, it won’t make much difference as your alternator can’t be fooled into overcharge the new one for any prolonged period.

Assuming the other 2 batteries are still good, you should be fine.

 

[Scott T-Bird]

If you really want your start battery separate from the house bank, you can use a DCP switch with an ACR, but before you consider it, you must read about the shortcomings. If you went that route, you would then want to provide isolation switches so that you can utilize one bank or the other in isolation for both loads in the odd case of battery bank failure. That is the system that I prefer, but others do not like it. My new (to me) boat has the standard 1+BOTH+2 switch and I hate it and will be changing the system to what I prefer over the winter.

 

[dlochner]

First, realize that on most production boats the factory charging and battery installation is not designed to be optimal. The primary consideration is cost; the cost to install and the cost of warranty claims.

Configuring a parallel battery bank is not as simple as + to + and - to -. The batteries must be configured so that the battery is part of the circuit and not just attached to the circuit. If the positive cable to the switch is off battery 1 the negative cable from the negative bus bar must be attached to battery 2. If both the negative and positive cables are only attached to battery 1, battery 2 is out of the circuit.

If the alternator is a stock internally regulated alternator it is not charging the batteries, especially the house batteries at an optimal level. Stock alternators are set up to recharge the starting battery quickly, which is easy because starting an engine requires very little energy. House batteries need to be more deeply charged and the regulator is typically not set up to do this.

How old is the battery charger? Is it a modern 3 stage charger? Older chargers kill batteries.

It is possible that the alternator is not charging the batteries at all. If your 1-2-Both switch is not a make-before-break switch, when the switch is thrown from 2 to Both the connection to a battery is broken which causes a voltage surge in the alternator that fries the diodes and renders the alternator dead.

Ideally all the batteries should be from the same lot. That becomes important to extend battery life if the charging system is optimized for battery life. Since the stock charging systems are not optimized for battery life, then this is less important. The system you have may be fine for your needs and sailing if you are primarily day sailing and taking short weekend cruises. If you goal is to cruise and spend long times away from a dock and charging, then a major upgrade is in order.

To better understand your charging and battery selection system start here:

1/2/BOTH Switch Considerations

1/2/BOTH Battery Switch Considerations - Ever wonder how to make the 1/2/BOTH switch easier to use, let this article explain how to do that.

marinehowto.com

 

[Davidasailor26]

Lots of thoughts above on how to improve your system as a whole, and those may be worth considering. But it sounds like your current setup is adequate for your needs, and you’re just looking to replace the starter battery. Since it sounds like you’re careful to only parallel the start battery with the house bank when charging I’d say you’re probably ok to just replace it with new. You don’t want a single bank with a mix of old and new batteries, but for the short duration charging that you’re talking about I think the mismatch should be tolerable.

 

[sailcapt340]

Wow! Did you open up a can of worms.
I, like you have the "exact" same setup (same boat). Now your going to find We have car alternators on our Yanmars, probably 60 or 80 Amp output. That require hours of running time to charge batteries.
Most of my friends with similar boats (even larger) have the same also, so your not alone. May make you feel good, may not.
You have received great information from everyone who has responded, and lots of reading and learning do to also. I for one will be reading the marinehowto article all winter long.
Like davidasailor26 said, your probably going to be all right adding a starting battery and not mixing it with the other two.
The Automatic Charge Relay is a good idea to add to your (our) system though and can only help to balance the electrical needs you need. Shouldn't be a major cost factor addon along with a new battery.
Sounds like you are switching from number 2 setting to Both each time, as long as you never go through the OFF setting while running you'll be fine.
I would match the new battery with the same Name, Size etc as you have as now. Mix and match doesn't work well in batteries.

 

[Stu Jackson]

Lots of thoughts above on how to improve your system as a whole, and those may be worth considering. But it sounds like your current setup is adequate for your needs, and you’re just looking to replace the starter battery. Since it sounds like you’re careful to only parallel the start battery with the house bank when charging I’d say you’re probably ok to just replace it with new. You don’t want a single bank with a mix of old and new batteries, but for the short duration charging that you’re talking about I think the mismatch should be tolerable.

^^^^^^^^^^^^^^^^^^^^^^THIS.

KISS. Very good advice from all the others, but like telling you how to make a watch when you're asking what time it is.

 

[dlochner]

^^^^^^^^^^^^^^^^^^^^^^THIS.

KISS. Very good advice from all the others, but like telling you how to make a watch when you're asking what time it is.

Yes, however, do you give a man a fish? Or teach him to fish?

 

[FastOlson]

This is starting to be fun!
Is that fish wearing a waterproof watch?

 

[Stu Jackson]

Yes, however, do you give a man a fish? Or teach him to fish?

Aw C'mon, Dave, you, among many others, know (I try to) do that all the time. I was just answering his question, and told him his advice from everyone else was just fine.

 

[Nichole340]

Reading over again all the posts is eye opening.
Reading “delochner’s” about the cable attachment...my 1-2-Both Switch has a Positive and Negative cable on both sides, making a total of 4 cables in all. sailcapt340 setup must be the same as his post says it‘s the same as my 2000 340.

So as it is configured now,
Side 1, a Positive cable (red) goes to the first battery of my House Bank (of 2 Batteries) as well as a Negative cable (yellow) to the first battery. Then another Positive cable connects to the Positive of the second battery and a Negative cable connects to the Negative of the second battery. That’s my 2 battery House Bank.

Side 2, has its own Positive and Negative Cable which connects to my Start Battery (1 battery)

As I see this, when my 1-2-Both Switch is set to Both...electricity is being sent to both battery banks.
My alternator may not be big enough to handle this, but that‘s a separate issue. Which I can address by adding a larger Alternator, Serpentine Belt System etc.
Since the batteries are off the boat now, I can’t use a multimeter to check if equal amounts of Volts, Amps, power is going to both sides at the same time. That may be the issue and the 1-2-Both Switch could be faulty.
The connections are clean and tight at the switch. The cables themselves are in good shape, they are dirty, but not cracked or frayed. And it could be I just had a bad battery.

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

 

[Maine Sail]

I charge using the Alternator with the engine during the season. (snip) I am on a mooring all season.

Using an alternator only, on a mooring sailed boat, especially an internally regulated one, is murder on batteries. Two years is actually pretty darn good!

All the batteries are very likely well beyond their useful life at this point. Batteries need to get back to 100% SoC after each use or they sulfate and die. Cheap G-24 pseudo deep-cycle batteries are not actually "deep-cycle" at all and die even sooner when absused.

What is a Deep-Cycle Battery? (LINK)

Unless you are running the alternator for 7+ hours after each discharge then you're not getting them anywhere close to 100% SoC.

Rx:
New battery or batteries (the others won't be too far behind the starter)
Add solar so the batteries can actually recharge after each use

 

[dlochner]

Aw C'mon, Dave, you, among many others, know (I try to) do that all the time. I was just answering his question, and told him his advice from everyone else was just fine.

@Stu Jackson I know you do.

Side 1, a Positive cable (red) goes to the first battery of my House Bank (of 2 Batteries) as well as a Negative cable (yellow) to the first battery. Then another Positive cable connects to the Positive of the second battery and a Negative cable connects to the Negative of the second battery. That’s my 2 battery House Bank.

This is incorrect. While you have 2 batteries in parallel, in practice only the first battery is being used. Electrons are lazy, they do a lot of work but basically they are lazy and want to get back home as soon and as quick as possible. When a device is used, the electrons travel through the device and back to the batter from which they came. In your set up, the electron leaves Battery 1 does its job and comes back to Battery 1 never passing through Battery 2. This places most or all of the current draw on Battery 1 causing it to reach lower partial state of charges than Battery 2.

The solution is relatively simple. Battery 1 Postive is connected to the Switch and Battery 2 positive. Battery 1 Negative is connected to Battery 2 negative. Battery 2 negative is also connected to the negative bus bar or engine ground. Now when the electron leaves Battery 1 it goes to work and comes back to battery 2 and on home to battery 1. This balances the load across both batteries and keeps the batteries equal in terms of state of charge.

The simple upgrade is to move the negative cable from Battery 1 to Battery 2. That will extend the life of your house batteries. There are articles on Maine Sail's website and in Musings with Main Sail here on SBO that go into great and more nuanced detail.