Mixing it up?

[ranger58sb]

Originally Posted by Hoohaa

Yes. This is what I have heard. I allready own these two different batteries, so am trying to find out what will happen if I wire them in sequence? Short term? Long term?
I can go and buy new batteries but it seems like a waste of the two that I allready own. Is it really an unknown quantity? If so, I don't have much too loose by giving it A go.

delmarrey
I am still trying to get my head around the links, thanks.

Even if the age old dictum is evolving to become only "same type" (see SL's very interesting post) -- versus "same size/type/age" -- I've always understood that guidance to be simply about getting the best performance and longest life out of a given set of batteries.

Batteries of different types accept charge at different rates, so that's why you'd want to have batteries in a bank all being lead acid, or all AGM, or all gel, etc. And then the charger would be set to handle the appropriate charging rate for that chemistry, and the appropriate duration for the bank size.

Assuming same type, and as long as all cells in each are OK at the start (see David's comment about hydrometers, which aren't expensive), combining your existing batteries probably isn't actually going to hurt anything. (I might think to modify that if one is a Lifeline AGM which can be equalized, and another is a different brand of AGM which cannot be equalized... but that's just guessing at an appropriately cautious approach... and I'm assuming you might not have AGMs anyway.)

And I should point out: I'm not an expert on this topic!

Can't say how much LESS performance or longevity you might experience, if any, but if it were me and the other choice were to sacrifice a couple of perfectly good batteries in favor of all new... I'd go ahead and combine 'em, use 'em until they crap out.

And still do all that stuff about isolating starting batteries from house bank, etc...

-Chris

[sailinglegend]

Originally Posted by ranger42c

...OTOH, an individual cell in a 245-ah 8D is sized differently than a single cell in a 100-ah Group 31. Hmmm.....

A very good point.

I would suggest that with any equalization programme - especially with open flooded batteries, you don't do them all at the same time because of the gas given off. Even with my AGMs I isolate them from the house loads and do them two at a time to stop 15.5 volts getting to any boat equipment. With different capacity batteries in the same bank I would equalize them based on their size.

[Badsanta]

I vote for more smaller batteries than a few large ones. I cant handle the 4 or 8 d's any more even the 31's are a pita.

[delmarrey]

Originally Posted by sailinglegend

A very good point.

I would suggest that with any equalization programme - especially with open flooded batteries, you don't do them all at the same time because of the gas given off.

This is why the USCG/ABYC requires vented battery compartments.

[Badsanta]

The off gasing is explosive?

[Hoohaa]

OK. Have just spent 8 days on board. Kept the batteries to high 11's most of the time. Part of my problem is with my wind gen's power diverter. But have found a way around that problem and am working to fix it properly. In other words I was not getting full performance From it.
I am going to add my spare batt to the house bank. Can someone please let me know the correct wiring?
Currently I have 2 wired in sequence. I assume I need to line them up in a queue. That is they must run 3,2,1 (1 being the batt closest to the business end) not 2,1 3,1. Is that correct? Due to the locations of the batteries it would be better to wire using the second option.
Thanks

[Kettlewell]

Maybe I am misunderstanding the question, but it doesn't matter what order you put them in if you are connecting in parallel--they will act like one big battery. It is a good idea to connect the ground from one end of the bank and the loads/charging at the other end of the bank.

[Hoohaa]

Originally Posted by Kettlewell

Maybe I am misunderstanding the question, but it doesn't matter what order you put them in if you are connecting in parallel--they will act like one big battery. It is a good idea to connect the ground from one end of the bank and the loads/charging at the other end of the bank.

Here is a sketch, Hope it doesn't confuse but I think I will go with your Idea. I guess the correct way to do it is on the left.

[Kettlewell]

Yes, the way on the left would be the best, but it sounds like you are draining your batteries too low in the first place either due to insufficient charging, insufficient capacity, or failing batteries, or most likely a combination of all three. If you connect all your batteries together it may allow you to limp along for awhile, but that is a recipe for ending up one morning not having enough power to crank over your engine. I would much prefer sorting out your main house bank to the point that it is sufficient for your needs, keeping the starter battery just for starting. You never know when you may need that engine to start in the middle of a storm in the middle of the night!

[Hoohaa]

I see what you are saying but. The charging issue is being sorted out, I currently have Alternator, 60 watt solar and D400 wind generator. Once the wind gen problems are sorted, it will have more than enough capacity (assuming we have wind). I can add additional solar later if I decide to cruise longer term.
The battery i am hoping to install will in fact be the 4th battery on board, as I already have a dedicated battery for the engine. The existing 2 batteries on the house bank, are only 6 months old and installed by marine electricians so all should be OK.

I have just got back from Jcar and bought the cable, crimper's and fittings. No turning back now.

[FlyingCloud1937]

Originally Posted by Hoohaa

I see what you are saying but. The charging issue is being sorted out, I currently have Alternator, 60 watt solar and D400 wind generator. Once the wind gen problems are sorted, it will have more than enough capacity (assuming we have wind). I can add additional solar later if I decide to cruise longer term.
The battery i am hoping to install will in fact be the 4th battery on board, as I already have a dedicated battery for the engine. The existing 2 batteries on the house bank, are only 6 months old and installed by marine electricians so all should be OK.

I have just got back from Jcar and bought the cable, crimper's and fittings. No turning back now.

Drinking hot tea on a hot day is like banging your head against a wall . It feels good when you stop.... "Terry" my dad.

[Hoohaa]

Just a quick update, I installed the battery but will not be back on board until next Friday. I will see how things go an and maybe post some pics once I strap it down.
Thanks for the help.