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

[S/V Alchemy]

Can't resist a good electrics pun, I'm afraid.

OK, to make this brief-ish: Let's assume I wish to make a six-battery, roughly 1100 Ah house bank. Assume I have all my charge sources sized correctly and adequately, and I have all the space I require close to the boat's CG. Assume I like Trojan products and the tall L16 form factor, although this is not a must-have if I can save a few hundred with an equivalent battery maker.

Would there be a case to favour six 2V batteries to form one big bank using this model of Trojan L16: Trojan L-16-RE-2V 2V, 1110AH (20HR) Premium Line Flooded Battery

or to go series/parallel with three pairs of 6V batteries of this model? Trojan Battery Company

The rationale for a bunch of massive two-volters is found here: http://navigatorpublishing.com/ondig...ad_edition.pdf


End result is the same, and I gather the 2Vs are more robust, but if one of the 6Vs went bad, would I not have the ability to remove its partner and simply fall back to a house bank 2/3rds the intended size?

I've got a feeling some of you could provide real-life-based guidance here. It's akin to those compartmentalized batteries Rolls sells, only bigger. Thanks.

[ontherocks83]

Are you traveling or staying local? My first thought is if you are in a distant land and one of those 2v's craps out can you get a replacement for it? If you are staying in your home area then never mind.

[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.

[jeepbluetj]

OnTheRocks is right - 6v's have got to be way more available.

So the pro's for the 6v's are:

Easier to replace.
A failed battery doesn't kill your entire bank.
I'd guess they're cheaper.

The 2v's are likely "better" as far as batteries are concerned.

Me? I'd go to 6vs. I have 6vs in the motorhome. 6vs in the boat.

[a64pilot]

Did I read that these 2V batteries were 119 lbs ea, and that of course you need 6 ea to get 12V, so that's 714 lbs of batteries?

1110 amp hours of battery, my God son, what are you powering? How are you going to charge them?

[TeddyDiver]

2 volts are all over, not just visible for everybody. Haven't seen a 6'r since.. err.. 40+ years. More reliable and more cycles with 2 volts. Better to have flooded cels thou.

[S/V Alchemy]

Originally Posted by a64pilot

Did I read that these 2V batteries were 119 lbs ea, and that of course you need 6 ea to get 12V, so that's 714 lbs of batteries?

1110 amp hours of battery, my God son, what are you powering? How are you going to charge them?

Our boat is steel, pushing 42 feet LOA and weighs 29,500 lbs. unladen. As I said, weight's not the issue and this will be essentially under the saloon stairs and over the keel tanks. The charge source include four 135 W solar panels, a 400W wind generator, and one 180 amp alternator or two 75-90 amp alternators, switchable to charge either house (default) or start batteries. I would keep the separate 12 VDC start and windlass batteries (probably Group 27s) charged via echo charging from this house bank.

I carry twice as much water than the weight of the batteries as internal ballast...about 180 U.S. gallons. Hell, I've got half a tonne of lead pigs just trimming out the bow until I get all my tools and spares down in the forward workshop!

[S/V Alchemy]

Originally Posted by TeddyDiver

2 volts are all over, not just visible for everybody. Haven't seen a 6'r since.. err.. 40+ years. More reliable and more cycles with 2 volts. Better to have flooded cels thou.

I agree on the flooded cells. This will be long-range cruising. AGMs, etc. are great if you are moored and sail on weekends, but I ideally want a house bank that can spend five days with no wind, no sun and no engine run-time before approaching 50% SOC.

Regarding the 6VDC L16s, though, they are quite common in forklifts, golf carts and in solar power storage setups in off-grid situations. While the 2V versions might be more reliable (but why?), the 6VDCs are not difficult to obtain.

[Cavalier]

I've looked at the Tall L-16 6V Trojans and like the look of them. We currently have two parallelized banks each of 4 lots of wet-cell serial-parallel 6V batteries, such that each bank is 12V.

If I could fit the Trojans in, I'd have gone for them but they're too deep for our battery compartments.

I think a single bank of 3 parallelized 2x6V (serial) L16s would be great!... If you do have an issue with one cell then you can always unhook a pair from the parallel system and maintain 2/3 capacity until you find a replacement 6V, which are much easier to come by, as the good people of this forum have stated.



We're running 2x130W Kyocera panels through a MorningStar Pro 60A controller.. I've just picked up an additional Kyocera 120W panel for eBay today to add into the system, giving a maximum of 360W into the system (if the boat's in close orbit around the sun and the panels are tangent to the photosphere )

[TeddyDiver]

Propane or dieselhydraulic forklifts here, no golf courses and emergency powers with 2v banks. Might be someones fjell cabins having 6v with solar, dunno. 2v's have thicker plates, more 'pilge' for the sh** buildup below the plates. You can also circulate the single cells (moving the last one to first place).

[TeddyDiver]

Originally Posted by Cavalier

I think a single bank of 3 parallelized 2x6V (serial) L16s would be great!... If you do have an issue with one cell then you can always unhook a pair from the parallel system and maintain 2/3 capacity until you find a replacement 6V, which are much easier to come by, as the good people of this forum have stated.

Not good to have parallel battery banks of different age together. Premature grave for the new battery. In this case best to buy three and set them as the first batteries for each paralled bank.
It's allways best solution to have only one bank, be it one 12v, two 6v or six 2v batteries in a series. Which one of those depends how big bank we are dealing with. Less than 150 Ah with 12v, over 300Ah with 2v single cells IMHO.

[Cavalier]

Originally Posted by TeddyDiver

Not good to have parallel battery banks of different age together. Premature grave for the new battery. In this case best to buy three and set them as the first batteries for each paralled bank.
It's allways best solution to have only one bank, be it one 12v, two 6v or six 2v batteries in a series. Which one of those depends how big bank we are dealing with. Less than 150 Ah with 12v, over 300Ah with 2v single cells IMHO.

Agreed with the best practices, however, the OP specifically asked for >1000Ah. That's not going to happen with single banks unless it's configured as a 48v system using 2v cells.. That's a lot of cells!

This is the dilemma faced by anyone constructing large Ah capacity systems. At some point batteries are going to need replacing. Do you empty your wallet and replace all of them, or do you just replace a pair at the risk of prematurely degrading the new installs? ...hard choices in a world without infinite cash and resources.



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.

[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
http://www.off-grid-europe.com/batte...-power-4700-2v?

My choice for OP
http://www.off-grid-europe.com/batte...-power-1070-2v?

[evm1024]

I've been looking at the same thing more or less. Everything from forklift batteries to 2v cells. Currently using 4 GC batteries and will go to L16 when we are ready to depart or the GC fail.

THe Trojan L16H are 435 AH each at 121 pounds. Rolls S600 are 450 AH and 131 pounds. 4 of the S600 is not > 1000AH but 900 is closer..... And what I'll likely use.

When mixing makes of battery be ware of slightly differing case sizes. The take home message here is make your battery box fit the largest battery and use spacers for smaller for a snug fit if needed. Be a shame to have a snug fit box for L16RE-B (11.575 x 7.125) and only have L16H (11.625 x 7.125) or rolls S600 (12.5 x 7.125) available.

To answer you original question I passed on the 2 V cells because in a pinch with L16 I can pull out a bad L16 and its mate and replace them with 2 golf cart batteries till I can source 2 new L16.

This may not help you as that going from 3 sets of L16 to 2 sets drops you from 1125 AH (3x375) to 750 AH (2x375) where as with only 2 sets of L16 I would drop to 375 AH. Add in a GC set (t105 at 225 AH) and get 600 AH in the 2 set case (375 + 225) and 975 AH in the 3 set case (2x375_225)

Of course you may not need to jury rig the house bank like this. ANd of course it is not optimal and had mixed capacities but same chemistry so it may not be too bad a compromise in a pinch.

[S/V Alchemy]

Originally Posted by Cavalier

I've looked at the Tall L-16 6V Trojans and like the look of them. We currently have two parallelized banks each of 4 lots of wet-cell serial-parallel 6V batteries, such that each bank is 12V.

If I could fit the Trojans in, I'd have gone for them but they're too deep for our battery compartments.

I think a single bank of 3 parallelized 2x6V (serial) L16s would be great!... If you do have an issue with one cell then you can always unhook a pair from the parallel system and maintain 2/3 capacity until you find a replacement 6V, which are much easier to come by, as the good people of this forum have stated.

We're running 2x130W Kyocera panels through a MorningStar Pro 60A controller.. I've just picked up an additional Kyocera 120W panel for eBay today to add into the system, giving a maximum of 360W into the system (if the boat's in close orbit around the sun and the panels are tangent to the photosphere )

Heh...I call the odds of reaching 100% with panels 10 to 2, which is roughly the four hours they work nicely. I have four of those panels and they'll goi to an Outback FX-60...once I put in more than a "minder" battery for the bilge pump. Having a custom boat means that if you are willing to redo part of the interior, you can have what you want where you want. I could have had a load of Northstar AGMs lying on their sides to do this, but centerline flooded cells anchored to the saloon side of the engine bay half-bulkhead with L-bar, and under a redone, securable gas-strutted set of saloon stairs, gives me security, easy access and a short run to the engine and the main panels, charger/inverter, etc. I also like having the batteries out of the engine bay. It will be bad enough having warm water from the tankage down there!

Thanks for your experience.