Does battery voltage configuration make a difference?

[slavco]

Hi All,

I'm starting to look for some new batteries as mine are now 11 years old. I'm running a 24v system off-grid, at my cabin and currently have 4 6v Surette s-530 batteries. Ideally, I want to stick with Surettes for a replacement, but of course there is number of different batteries they offer. From some of the reading I did on here, it looks like the ideal config is to run the batteries in series only (avoiding parallel strings) for optimal charging/discharging. Even still, I could go with 12 x 2v or 6 x 4v or 4 x 6v or 3x 8v (all configs have similar AH capacity). My question is, are there any advantages / disadvantages (other than cost) with going with 4 6v batteries vs. 6 4v batteries if the AH is the same?

Thanks!
Slav

[Tecnodave]

Slav,

Stick with the Surette L-16's they really work, mine are 14 years old this week and still at full capacity. The S-530 line has been replaced with the S-550 line. When you go to 1100 a.h. or so consider 2 volt cells so you will not have strings in parallel, but if those S-530's served you well then work with what you have proven to work.

The 4 volt and 2 volt cells are appropriate for larger systems. Do avoid parallel batteries, they are problematic.

[slavco]

Slav,

Stick with the Surette L-16's they really work, mine are 14 years old this week and still at full capacity. The S-530 line has been replaced with the S-550 line. When you go to 1100 a.h. or so consider 2 volt cells so you will not have strings in parallel, but if those S-530's served you well then work with what you have proven to work.

Thanks Tecnodave. You're right, they've worked well and are still chugging along but getting tired. My challenge right now is, I need a bit more reserve capacity... so in your opinion, do you think I'd be ok to go with 8 S-550's in series/parallel to get up to 850ah ?

[Tecnodave]

My next bank will probably be 2 volt Surette L-16's at 1100 a.h. to avoid parallel issues but 2 banks in parallel is workable, but do be sure to have balanced wiring, equal lengths and not just jumpered from one bank to the other haphazardly. Can't remember the full website but

smartguage.co.uk has a complete section on proper battery wiring, I will get that complete u.r.l. and post it here if you need it.

[Mike90250]

Hi All,

....... My question is, are there any advantages / disadvantages (other than cost) with going with 4, 6v batteries vs. 6, 4v batteries if the AH is the same?....

One way, you save on interconnect cables.
other way, you save if one cell dies, and you have to replace it out of warranty.

For me, it would involve the ease of moving batteries in and out at replacement time, and ease of layout with larger or smaller batteries.

Electrically - no difference. Still the same number of cells to water. Big savings over parallel strings, with lots of smaller cells to water

[Tecnodave]

Mike90250,

I totally agree with you on that, I can move an L-16, a bit at a time, but I don't need a crew, a big factor for me, and the L-16 is easier to handle than a D-8 at the same weight, I keep peeking at your Ni fe cells, that is a clean installation, probably about the same weight, 125-140. Lbs?

[Mike90250]

Mike90250,

I totally agree with you on that, I can move an L-16, a bit at a time, but I don't need a crew, a big factor for me, and the L-16 is easier to handle than a D-8 at the same weight, I keep peeking at your Ni fe cells, that is a clean installation, probably about the same weight, 125-140. Lbs?

Filled, they are about 100#, I don't have the density of lead, just nickel and iron. That's still quite enough !

[inetdog]

My next bank will probably be 2 volt Surette L-16's at 1100 a.h. to avoid parallel issues but 2 banks in parallel is workable, but do be sure to have balanced wiring, equal lengths and not just jumpered from one bank to the other haphazardly. Can't remember the full website but

smartguage.co.uk has a complete section on proper battery wiring, I will get that complete u.r.l. and post it here if you need it.

http://www.smartgauge.co.uk/batt_con.html

[slavco]

http://www.smartgauge.co.uk/batt_con.html

Thanks for the link, it definitely helps!

I did some more reading last night as well as costing, and decided to skip the 4v batteries.Instead, I narrowed it down to 2 options. I'm thinking of either going with 12 x 2v Surrette S-1450 (http://www.rollsbattery.com/wp-conte...ies/S-1450.pdf) which would give me 1100ah but is more $$ and would of course require more interconnects OR simpler/cheaper option of 8 6v Surrettes S-550 which would give me 850 ah. - not the most efficient setup but the cost difference is about $2300 less for the S-550's which is not insignificant.. I'll need to have a chat with the Mrs.

Thanks for all the input gents, much appreciated!

[Tecnodave]

At that price difference, I'd stick with the S-550's, 2 banks in parallel, but do read the smart guage paper, they spell it out for you clearly.