Starting Battery won't hold a charge

[Scott T-Bird]

I only responded with the DCP option because it always pricks my ears when I hear somebody say (or read) something about their "start" battery when talking about the 1+2+Both switch. You do realize that you don't really have a dedicated "start" battery. It doesn't matter which position the switch is at. It can be 1, it can be 2, or it can be Both, any way you do it, the house loads are combined with the starter. Only the source changes, not the loads.

For that reason, I see absolutely no reason to switch the battery selector to 2 when starting the engine. What does that accomplish? If there is a reason, I'd be happy to read all about it! In reality, all you are doing is starting the engine with the reserve battery, with all of the house loads combined. What would be the purpose? I think it leads to killing the reserve battery when it doesn't get charged while the selector is on 1. I don't see the point in using the selector switch to direct charging current. That is what leads to problems in my opinion.

 

[Stu Jackson]

because it always pricks my ears

Well, Scotty, for the bazlillionth time: it is a RESERVE bank. It is NOT a dedicated START bank. You should know this. The reserve bank becomes immediately available with the flick of the 1-2-B switch, no re-wiring is required BECAUSE the VERY WORST thing one can do is COMBINE a dead bank with your remaining GOOD bank. Which, as the link I provided earlier clearly explains. That is why I dislike the DCP switch you keep bringing up, BECAUSE the DCP switch ONLY allows you to COMBINE a good bank with a dead one. That is simply NOT GOOD. I agree, that YES, it completely separates the start bank from the house bank in normal use.
Did I mention all this is already in the link?
The DCP is OK for those who KNOW what it does and can live with it, and, as the LINK explains, is good for smaller runabouts who start their engines often in any given day and want to keep their electronics separate.
Yes, Scotty, it DOES have an advantage.
I just believe that the disadvantages far, far outweigh the advantages.

If there is a reason, I'd be happy to read all about it!

This one: (yet again)

AGM Battery Issues and the Blue Seas Dual Circuit Switch (from Maine Sail) "DARN AGM Batteries"
Darn AGM Batteries

Take a minute and please read it, since you asked...

This whole issue is one of options.
Your boat, your choice.

 

[Scott T-Bird]

Well, Scotty, for the bazlillionth time: it is a RESERVE bank. It is NOT a dedicated START bank. You should know this.

As usual, your comprehension is lacking. You are simply repeating what I have said and insinuating that I have said something different. In my last post, I said that with a 1+2+Both switch, there is no dedicated START battery. The point that I was making is that some people seem to make the assumption that they are using a dedicated START battery when they put the switch on position 2. You are agreeing with me that the bank is a RESERVE bank, not a START bank, yet you can't even recognize that fact because you have a comprehension problem.

I'd bet that under normal circumstances you start your engine with the selector switch on position 1. When have you used position 2? Ever? Only when Bank 1 fails? If you do start your engine normally on position 2, do you have a reason? If so, please explain!

 

[Stu Jackson]

You are agreeing with me that the bank is a RESERVE bank, not a START bank, yet you can't even recognize that fact because you have a comprehension problem.

Why are you casting aspersions? What the heck did I ever do to you? I answered your question. I even agreed with you. I DID "...recognize the fact..."And this is what I get back from you?

I'd bet that under normal circumstances you start your engine with the selector switch on position 1. When have you used position 2? Ever? Only when Bank 1 fails? If you do start your engine normally on position 2, do you have a reason? If so, please explain!

Yes, my house bank is #1, my reserve bank is #2.
And yes, I have used position #2. Not only when bank #1 fails, but regularly to assure that while the voltage is fine it can actually start the engine, which is what it is there for, right?
Less than two months ago I was out on an overnight cruise. I had been noticing my house bank voltage sagging more than usual, and knew it was getting time to get a new house bank after six years.
#1 wouldn't start the engine.
So, I simply switched to #2, turned off all house loads first of course, and started up and got home safely.
See? No undoing wiring, because the very last thing I wanted to do was combine my good reserve bank with my failing house bank.
One switch. Of course there are other ways. I don't disagree with you, I've said that I just dislike it and why.
What's so hard?
Is that enough explanation for you, or are you going to continue to be rude?

 

[Scott T-Bird]

You started the rudeness. I simply pointed out that you were agreeing with me, yet you didn't seem to know it. Your explanation is great! Basically you are saying that your normal use includes starting the engine with Bank1. You seem to only use your Reserve bank for when you absolutely need it, or when you simply want to verify that it is healthy.

BTW, your example from earlier this year is a perfect endorsement for DCP switch. If you had a DCP switch, you would start your engine under the normal circumstance whereby you would simply turn the switch ON and start your engine. The START battery wouldn't be affected in the least by your weak HOUSE bank. There would be no reason to "undue" any wiring. Your banks are already isolated, so there is no need to do anything out of the ordinary, and you certainly would have no need or desire to put the switch in the COMBINED position. You wouldn't even have to turn off your house loads because the isolation means that your START battery isn't even affected by the house loads. With your engine running, your alternator would automatically be charging your weak HOUSE bank. No need to change positions on the selector switch to direct charging. There! Simple solution working elegantly with DCP switch!

 

[Stu Jackson]

BTW, your example from earlier this year is a perfect endorsement for DCP switch. If you had a DCP switch, you would start your engine under the normal circumstance whereby you would simply turn the switch ON and start your engine. The START battery wouldn't be affected in the least by your weak HOUSE bank. There would be no reason to "undue" any wiring. Your banks are already isolated, so there is no need to do anything out of the ordinary, and you certainly would have no need or desire to put the switch in the COMBINED position. With your engine running, your alternator would automatically be charging your weak HOUSE bank. No need to change positions on the selector switch to direct charging. There! Simple solution working elegantly with DCP switch!

I understand this, Scotty.
Then, please explain what the Emergency position on the DCP is actually used for in real life.
Thanks.

 

[Scott T-Bird]

Well, I actually have not had a reason to use the "COMBINED" position. As you probably surmise, my START battery is actually a reserve for the HOUSE bank, just as the HOUSE bank is also a reserve for the START battery. Essentially, I have both banks useful as a reserve. I also have no need to periodically "test" my reserve banks. They are in constant use and both are monitored.

If my START battery fails, I can disconnect it with a simple ON-OFF switch and set the DCP to COMBINED. There, house and start loads on the HOUSE bank and no connection with the bad START battery. If my HOUSE bank fails catastrophically, I can disconnect it with an ON-OFF switch and set the DCP to COMBINED. House and start loads on the START bank and no connection with the failed HOUSE bank.

If the HOUSE bank simply runs down to a weak charge, as in your example, I wouldn't bother selecting COMBINED. I would just start the engine like normal and be on my way with the alternator charging the HOUSE bank back up.

Admittedly, if my START battery simply suffered from a weak charge and there wasn't anything catastrophically wrong with it other than a weak charge, I could simply start the engine with the DCP set to COMBINED. I wouldn't leave it in COMBINED after shutting down the engine/alternator. Bad practice? Possibly, but no worse than doing the same thing with the 1+2+B switch.

 

[Davidasailor26]

Well, I actually have not had a reason to use the "COMBINED" position. As you probably surmise, my START battery is actually a reserve for the HOUSE bank, just as the HOUSE bank is also a reserve for the START battery. Essentially, I have both banks useful as a reserve. I also have no need to periodically "test" my reserve banks. They are in constant use anyway.

If my START battery fails, I can disconnect it with a simple ON-OFF switch and set the DCP to COMBINED. There, house and start loads on the HOUSE bank and no connection with the bad START battery. If my HOUSE bank fails catastrophically, I can disconnect it with an ON-OFF switch and set the DCP to COMBINED. House and start loads on the START bank and no connection with the failed HOUSE bank.

If the HOUSE bank simply runs down to a weak charge, as in your example, I wouldn't bother selecting COMBINED. I would just start the engine like normal and be on my way with the alternator charging the HOUSE bank back up.

Admittedly, if my START battery simply suffered from a weak charge and there wasn't anything catastrophically wrong with it other than a weak charge, I could simply start the engine with the DCP set to COMBINED. I wouldn't leave it in COMBINED after shutting down the engine/alternator. Bad practice? Possibly, but no worse than doing the same thing with the 1+2+B switch.

So if you have 3 switches anyway, why is the DCP switch better than just a third on/off switch used as an emergency Combine switch? Basically like Maine Sail’s recommended Beneteau switch improvement at Z-Beneteau Battery Switch Wiring Upgrade.jpg by Compass Marine How To. It seems like 3 plain on/off switches would be less expensive than two on/off and one DCP. Is the DCP just more intuitive for you or is there some other advantage I’m missing?

 

[Ron20324]

...So if you have 3 switches anyway, It seems like 3 plain on/off switches would be less expensive than two on/off and one DCP. Is the DCP just more intuitive for you??

Oh, bless your heart David. I added a 3rd battery and RED switch to my B323. I rewired so there is a strong cable between the outputs of the 3 switches, so effectively making it a 12-volt buss. Pick any of the 3 switches to use whenever you want, and call them whatever you want. Whatever switch is on when you put the key in the ignition key slot in the panel, whatever battery is turned on becomes the "start" battery. That works until the sails are up. Engine off, turn the one off and the 2&3 on. At the night anchorage, while motoring around, the engine will top-off/charge the 2/3 batteries for overnight use. Morning, the off line battery is ready to back up if needed. IIRC, I sent that wiring schematic to Stu once?

 

[Scott T-Bird]

I haven't been exposed to the Beneteau switch configuration or the improvement that Maine Sail recommends. I'd guess that there really isn't any difference. The DCP just seems more intuitive & simpler. 99.9% of the time, you simply turn the DCP to the ON position. The 2 isolation switches are out of sight and always On. The only purpose of the 2 ON-OFF switches is emergency use, so they are hidden in a compartment near the batteries. The expense isn't really a factor, is it?

 

[Stu Jackson]

I sent that wiring schematic to Stu once?

Yes, and thanks. You've reminded me I still have to figure out a short way to present it whenb this comes up. My concept was to combine Maine Sail's ideas and your great one.

 

[Ward H]

The DCP just seems more intuitive & simpler. 99.9% of the time, you simply turn the DCP to the ON position. The 2 isolation switches are out of sight and always On. The expense isn't really a factor, is it?

The other advantage that led me to install the DCP switch is panel real estate. I don’t have room to have three battery switches ganged together near the DC panel or another convenient location.
If I did I probably would have used the 3 On Off switch method.

 

[dlochner]

Gentlemen, I think we can all agree there are many ways to skin a cat or wire a battery switch. A perfect solution for one boat and one sailor is an imperfect solution for another. There are some common key principles to keep in mind.

The solution should:

• allow for simultaneously charging both battery banks whenever a charge source is present;
• allow for easy isolation of either bank in the case of a bank failure;
• allow for either bank to provide power to critical functions, like starting and communications and navigation electronics;
• prevent accidental unloading of the alternator to prevent damaging the alternator diodes;
• be simple to operate.

The old style 1-2-Both switch doesn't meet these criteria unless a ACR or echo charger is added to charge both batteries. The DCP+ switch will meet these criteria if isolation switches and an ACR or echo charger is added. (The Beneteau 3 switch method is not one I'm familiar with.)

Different boats present different issues and personal preference will dictate which solution works best for any particular boat. @Stu Jackson obviously prefers a 1-2-Both solution, others like @Scott T-Bird and @Ward H have prefer a different approach.

I prefer the set it and forget it approach of the DCP+ switch.

Now let's discuss something far less controversial like varnish preferences.

 

[Scott T-Bird]

I think that 1+2+B switch meets all the criteria above, even without ACR. You forgot the one reason why the DCP switch is desirable:
Isolation of Start & House LOADS under normal use. This is the only function that 1+2+B doesn't meet. Admittedly, DCP really requires an ACR and it requires two isolation switches to provide the necessary functions. That pretty much goes without saying.

Somebody once posted a diagram that showed how all the criteria could be met with desired isolation of Start & House loads with two 1+2+B switches. I had to study the wiring diagram to understand how it would work and it was confusing, but it was a valid solution. I can even understand why you would do it if you were starting with a 1+2+B switch and all you had to do was buy another one.

In any case, I think the 1+2+B switch is a legacy from the old days when you needed to direct charge to targeted sources (battery banks) thru the switch. With the use of ACR and/or smart chargers, these days, it is not necessary.

 

[Garbonzo]

WOW, when you have 4 pages of comments and endless bickering, it is MUCH better to just go over to HOWTO then try to comprehend all of this. No wonder folks get confused... Simple question, but endless answers. SO I will make it simple.

Original question. Answer. Starting battery is bad get a new one.

Rest of story on system. Answer. Many ways to skin a cat, get on HOWTO and read up over the winter and then decide what you want to do. Consider donating to Rod to keep him going and posting. That is what I do..

 

[Garbonzo]

Stu and Scott... Last poster is ALWAYS the loser.. Keep that in mind.

 

[dlochner]

WOW, when you have 4 pages of comments and endless bickering, it is MUCH better to just go over to HOWTO then try to comprehend all of this. No wonder folks get confused... Simple question, but endless answers. SO I will make it simple.

Original question. Answer. Starting battery is bad get a new one.

Yes the simple answer is get a new battery. However, as the discussion evolved it became apparent that the OP had made an error when the batteries were installed. Simply replacing the battery without understanding the early death would simply cause a second battery to fail soon.

The simple answer is not always the best answer. Understanding how and way a system works or doesn't work will always lead to better outcomes. The OP now has an awareness of the multiple issues with designing or upgrading an electrical system, has a list of resources to review, and a long winter to think about how she wants to proceed. Those are the wins for the OP and the sometime circuitous discussion.

 

[Garbonzo]

So lets see what the OP actually does with this treasure trove of information, if really interested. 2 step approach above is still better than actually reading your way through this. I do like the bickering tho, it is cute..

 

[Nichole340]

I’ve been reading and watching this all take place. Who’s right, who’s not so right.
The fact is I caused this problem with wrong wiring this spring. I was in a hurry, I made a mistake. Thankfully it wasn’t worse. Having it pointed out was the best news I could have gotten. That problem will forever be corrected.

I’ve tested these batteries both Volts and Hydrometer and plan to buy 3 new batteries this spring.
I will be on the boat more now so the thought of a larger House Bank (1) for refrigeration use (occasionally) will come into the picture, wired correctly.
A single battery would be Reserve (2), as suggested.

To start changing the existing, a perfectly good 1-2-Both Switch, is not what I plan to do, and truth be told I really can’t see anyone doing that on their own boats, if it wasn’t really necessary. Most wouldn't even consider that job and would hope they would never have to.
I plan the ACR addition, seems like the right idea, and have a real Reserve Bank.

Actually, I’m glad this happened now. The batteries weren’t new and if I had to do this, it’s better to them than brand new ones.

The idea of a solar panel, a small poratble type, not the full Arch Mount. I'm not that type of off shore sailor or running all kinds electronics etc., is still an option.
A comment about the type of solar panel and size, was asked but it got lost deep in here somewhere. I think a solar panel wouldn't do any harm and would help.
More reading on Volt size and Amp output though, because I'm not about to start causing another problem.

Hopefully others will see my very crude drawings of my wiring and the correction made to it. If they have the same they can correct it as well. It was mentioned in here also, someone had the same wiring I had on their boat from the factory.

The information we all get from this site is invaluable. This is where we come to learn and fix. Sometimes you have to weed through it, but it‘s all well meaning.
At least from my perspective, I‘ve been given great help, guidance, correction and advice on this subject and thank everyone for it.

 

[Ward H]

The fact is I caused this problem with wrong wiring this spring.

Having the negative on the wrong end of your house bank didn’t cause your ”start” battery to go bad. It just wasn’t optimum for your house bank batteries life. Your “start” battery may have died due to chronic under charging or it just was at its end of life.

I plan the ACR addition, seems like the right idea, and have a real Reserve Bank.

That is a very good way to go and will be money well spent.

I think a solar panel wouldn't do any harm and would help.

That is the proper way to go since you’re on a mooring. Sorry I can’t offer guidance on size or setup, I have no direct experience with it.