If you were me, and all else was equal(ized)

[S/V Alchemy]

Originally Posted by TeddyDiver

You can also circulate the single cells (moving the last one to first place).

Well, that's an aspect I didn't consider. Thanks.

[S/V Alchemy]

Originally Posted by ontherocks83

also if I am reading this correctly if one of your 2v's craps out you just lost your entire bank where like you said if one 6v dies you can re-wire it to just have a smaller bank.

Yes, that is certainly a consideration. Six 2VDC batteries is an all-or-nothing proposition, even if they have intrinsic advantages in construction and in dealing with potential sulfation issues. Thanks.

[S/V Alchemy]

Originally Posted by Cavalier

IMHO it's better to go for one large bank which you cycle less-deep (and therefore lasts longer) than splitting up the capacity into smaller switchable banks which are going to cycle deeper and have a shorter life as a result.

That is very much my logic. Given that I should be able to "dump" wind and solar into the large bank (which can absorb more than a smaller bank) and that I can draw them down via echo charging to keep start and windlass batteries (which back each other up) along with the usual lights, appliances and fridge, I hope to cycle in a narrower range than would a boat with a more typical 480 Ah house bank.

I would also have the ability by altering set points on my charger to attempt "on the go" (or on the hook) equalization, as I will also have two Honda 2000s, a lessy "lossy" choice for, say, ten minutes of paint spraying or the use of a drill. That's the game plan, anyway. It only sounds complicated.

[S/V Alchemy]

Originally Posted by TeddyDiver

There are single cells up to thousands of Ah's. What I am looking to buy are allmost 1000Ah and they are close on top of the list (ascending order)..

Big one
Hoppecke 26 OPzS solar.power 4700 2v - Hoppecke - Flooded Lead-Acid - Batteries?

My choice for OP
Hoppecke 7 OPzS solar.power 1070 2v - Hoppecke - Flooded Lead-Acid - Batteries?

Interesting (the ones you've suggested), but about 30%-40% more expensive than the Trojans I'm looking at. When I bought the boat, it came with two T-105s that were 18 years old, and were only beginning to fail to fully charge.

It made a favourable impression, although I'm aware that there are other manufacturers (Surette, Deka, Crown, etc.) who are likely equally as reliable and well-built. Flooded batteries are well-understood and companies that take shortcuts in plate size or plate separation, etc. are relatively easy to spot. But I think with things like hydro caps, electrolyte monitoring and temperature control (little fans to circulate air in the box), one can easily get more than five years out of a bank.

[Cavalier]

Originally Posted by S/V Alchemy

I would also have the ability by altering set points on my charger to attempt "on the go" (or on the hook) equalization, :

The MorningStar Pro has an auto-equalization setting in software when set to the "Flooded Cell" setting. It's timer based and performs this automatically once a month (I think) based on a timer and when the panels are at full output.
I discovered this by accident when I was working on the boat one day and I heard the batteries gurgling. I ran to the battery monitor to notice that the voltage was way higher than I'd like for float or even absorb charging. After verifying this with a multimeter I disconnected the MorningStar thinking it was broken.
After researching "Morningstar failure modes" online looking for evidence of a foolish power design where the FETs and/or TVSs would short during failure, permitting full panel voltage through to the batteries, to my surprise I discovered that it was meant to do this as part of an equalization program!
I bashfully reconnected the MorningStar with a quiet look of being admonished on my face (well I am English so that's how I look anyway) vowing to read the manual next time!

Apparently, if you switch the unit from "Flooded" to "Sealed" the only difference is that it doesn't automatically run an equalization program.

[Cavalier]

http://www.morningstarcorp.com/products/prostar/



Click manual (top right): go to page 12. Auto-equalization run for 1 hour every 25 calendar days.

[deckofficer]

How about the best of both worlds? The robust construction of single cell and bank redundancy, with the added benefit of not being back breaking 120 lb cells.

Put together (2) strings of 2 volt cells in series and hook up through an A, B, Both battery switch. Leave it on Both, but if you should lose a cell, switch to the other bank.

each cell 70 lbs 648 ahr, so 1296 ahr, a bit over the capacity you want but close.
Concorde Sun-Xtender VRLA Sealed AGM Batteries

[alamoana]

13 Years and running with FLA Rolls 4000 series 275 AH, 12 volt batteries, no shorebreak POWER, constantly on a mooring.

[alamoana]

Originally Posted by alamoana

13 Years and running with FLA Rolls 4000 series 275 AH, 12 volt batteries, no shorebreak POWER, constantly on a mooring.

Did not finish writing.... 4 batteries for a 1100 AH bank, charged mainly with auxiliar alternators, 2 x 110 amps.
Hard to beat hindsight....or maybe it was good luck but seems to work OK for me.

[Boulter]

Originally Posted by TeddyDiver

You can also circulate the single cells (moving the last one to first place).

Are you suggesting physically moving cells in a rotation? Why would one want to do this?

Boulter

[TeddyDiver]

Originally Posted by Boulter

Are you suggesting physically moving cells in a rotation? Why would one want to do this?

Boulter

Yes. It's not essential but there are two reasons I'd consider doing it. First with a multicell battery going bad it's most often been the first cell failed here in cold climate, if too hot some of the middle ones. Rotating single cells (maybe twice a year) equalizes any environmental variations affecting battery life. Secondly If I'm rotating I can have a spare battery included in the rotation which solves the very unlightly problem of loosing one cell suddenly.

[ontherocks83]

Originally Posted by TeddyDiver

Yes. It's not essential but there are two reasons I'd consider doing it. First with a multicell battery going bad it's most often been the first cell failed here in cold climate, if too hot some of the middle ones. Rotating single cells (maybe twice a year) equalizes any environmental variations affecting battery life. Secondly If I'm rotating I can have a spare battery included in the rotation which solves the very unlightly problem of loosing one cell suddenly.

Man you are motivated!

I get and understand your logic but personally there has to be a point where enough maintenance is enough maintenance.

[Fuss]

Originally Posted by ontherocks83
also if I am reading this correctly if one of your 2v's craps out you just lost your entire bank where like you said if one 6v dies you can re-wire it to just have a smaller bank.

Originally Posted by S/V Alchemy

Yes, that is certainly a consideration. Six 2VDC batteries is an all-or-nothing proposition, even if they have intrinsic advantages in construction and in dealing with potential sulfation issues. Thanks.

Actually, thats not true that you have lost your entire bank with 2v cells.
Disconnect the faulty 2v cell.
You have a perfectly usable good bank for an emergency and it is running at 10v.
Start your engine and bring it up to 12, all will work as before with the same number of amps.

2v cells are actually the perfect solution for a dropped battery situation.

We are talking an emergency here, so you have to run your alternator more... be sure to monitor and not go over 13v and no damage will be done.

as soon as possible buy another 2v cell.

[Cavalier]

Originally Posted by ontherocks83

I get and understand your logic but personally there has to be a point where enough maintenance is enough maintenance.

Dunno man. I pride myself in draining all the batteries at least once a week, taking out each lead plate and polishing them by hand. Dehydrating the electrolyte prior to reconstituting the acid with my under-the-saloon table chemical lab, just to ensure that they're optimum in condition. Anything to get that last Ah of capacity out of them... :gormlessgoofylook:

[ontherocks83]

Originally Posted by Cavalier

Dunno man. I pride myself in draining all the batteries at least once a week, taking out each lead plate and polishing them by hand. Dehydrating the electrolyte prior to reconstituting the acid with my under-the-saloon table chemical lab, just to ensure that they're optimum in condition. Anything to get that last Ah of capacity out of them... :gormlessgoofylook:

If you put that much energy into a girlfriend instead, you'd have way better stories to tell on here