Can Surrette cells be replaced

Freewilley

As discussed on other thread, I regularly see middle cells lower than ends. Can the middle cell be replaced with an end cell from another battery? 
Surrette 550 is the corpse.

thanks!

Vic

Hi Freewilley,

Almost anything is possible,   but would guess that this surgery on L-16s would not be worthwhile,   and would be quite messy (IMO).

As you probably know,   the Surrette 5000 series that are composed from multiple cells (4 V and above) in a single case almost  always use 2 V cells that are bolted together.  On these batteries,  the top cover is easily removable,   allowing easy cell shuffling,  or replacement.   One only needs to choose among cells with;  flag terminal on the positive,  negative,  or NO flag terminals (for intermediate cells).  This battery series is quite a bit more expensive compared to their 4000 series,  for the same Capacity,   but can be worth the added $$.

While you may have a maximum charge rate in the 8 - 9% range,  it is possible that you could use some additional PV power (guessing).

Also,   with two parallel strings,   hope that you have a DC Clamp Ammeter to allow you to monitor string balance,   and perhaps take steps if you see a divergence in current balance ...

FWIW,    Vic

Freewilley

Right now I am only on 2 batteries. I am using generator quite a bit especially at meal times. To get back to four batteries I will have to buy another new one (I have a brand new one waiting to be used, but I do not want to mate it to these problem batteries).

But I think what you are saying is that while cells may be replaceable, they are not interchangeable? To be more specific, can I take an end cell from one battery and put it into the middle of another?
What I have now is 3 batteries that all have deficient middle cells.  I could end up with 2 better units if I scrap the worst one and harvest the end cells.

I would be getting a battery shop to do this, and I could have started by asking them if they will...but I just trust the experts on this board more than any shop...

Vic

Freewilley,

Have never seen an L-16 battery that was intended to have individual cells serviceable.   I was referring to Surrette's premium battery series  --  the 5000s.  Surrette L-16 sized batteries are in the 4000 Series,   and NOT intended to be serviced.

In 6 V L-16s,  the top cover is thermally welded onto the battery case.   The internal busbars that connect each cell are not meant to be disconnected,   they would need to be cut.

Some batteries that use soldered busbars can be serviced,   Forklift batteries are in this category.

It is just my opinion,   but,  cannot imagine that any battery shop would find the task of cutting off the top of an L-16,  sawing the busses,   removing cells,   swapping them,  somehow welding the top back onto the refurbished battery at all attractive,  OR economically viable.   One other problem might be,  dealing with the battery terminals,   particularly,   sealing the terminals on the refurbed battery.

Almost everything is possible,  but,  in this case,   at what cost?

Again,  just my opinions.   Good Luck,   Vic

Freewilley

So a Surrette 550 is an L16 battery?

I thought these were 3 individual 2 volt cells....and that is why they were replaceable....

SolarMusher

These Rolls batteries are only 3 years old, you'd be better to equalize each serie separately if they need it.
Do you have a battery killer in your cabin, something like a 120Vac fridge?
Try to set you Absorb voltage to 15V in your FM and let it absorb for 4 hours. Also disable end amps in Advanced (set it to 0) to be sure that they will use the absorb timer.
Erik in Qc

Estragon

@Freewilley - all lead acid batteries are made up of individual 2v cells. Most have the cells connected in series to give desired voltage using connections intended to be permanent (eg welded together then encased in a closed plastic case).

Some surretes have cells bolted together and are enclosed in a secondary case. I don't think the 550 is made that way though.

Vic

Freewilley,

YES,  the Surette S-550 batteries ARE L-16s  (this is really a Case Size).

And,  Estragon is correct,   all Lead Acid batteries have 2 V Cells,   many times,  connected in series to give the battery voltage that is needed.

Have attached a pic of a very different Surrette battery.   It is in the 5000 Series,   and has individual cells that ARE bolted together,  in this case,   to yield a 4 V  battery.

The L-16 Surrette batteries are constructed differently,   with three 2 V cells welded in series to give a 6 V battery,  that is has a case top that is bonded to the case,   has permanently connected 2 V cells,   and is not designed for case top removal,  or for replacing cells.

Vic

Lumisol

I would think it's best to replace the battery rather than the cell within it.

Freewilley

Hey thanks to all, and especially Vic.

Now I understand the construction...I have been around Surrettes for many years and this is the first time this was explained so clearly.

As to the problems with the strings, I will be setting these out in another thread, and looking for advice. I had never been told to change the end amps setting before.
thanks aganin

SolarMusher

Hi Free,

What was your abs time and end amps settings for the FM60? Rolls batteries like long absorb.

Did you disconnect this fridge last fall?
If all other cells are 1.260 and higher, I would give it a chance before to change for a new one (EQ 15.8V/4 to 8hrs).

If you really need, I can supply/send Rolls batteries from Barrie, On.
A+
Erik

Freewilley

I do buy from Barrie so I am interested in your info. I have dealt with Dommel Valley, is that you?
In the winter I have no power on at all. I have just put the Killawat back on the fridge because I lost my note, but it draws about 1kwh per 24 hours, I will confirm tomorrow.
There are long threads here about my system going back 4 years. Ugh.
I have been coached by Steve (chief tech at Surette) who spent hours with me. To no avail, really. These 4 batts were rnew under warranty in 2014. One was replaced again this spring, but I have not put it into service. The middle cell was DEAD.
I did modify the system somewhat in 2014 and added more PV. I also became aware I did not have RTS hooked up, but I do now.

From Steve, I basically set the system to absorb permanently by setting the float to 15. So it is not the absorb time....they get up that level and keep on. If I do not run an EQ they quickly (in a few hours) run to float or BAT FULL.even though the SG will be in the 1.200 range.

I would have to review my notes to see all that has been tried, just don't have time right now....but this is a great solar day and the batts have EQd for 6 hours with hardly any power drawing, and the middle cells are 1.245 and 1.240. Ends are about 1.260. All adjusted for temp.
This is as high as I can get them to read, even after an EQ all day. They have had at LEAST a dozen 7 hour EQ cycles in the last 3 weeks.
Of interest  maybe the temp of the acid. I lost my thermometer, but the adjustment thermometer on the hydrometer says to add 6 points...that gives you a sense of the temp I am sure....it seems that they are not getting as hot as I would expect, whatever that means.

The battery I have off the system right now is not as good as these two. And the fourth, as said, is a brand new one replaced under pro-rated warranty.
That is why I am thinking I will go with a brand new string and an old string and  install a switch so I can start out fresh, but not scrap the 2 batteries I am playing with,....as they seem to be useful for now, but not ok to wire all together.
thanks again!

SolarMusher

Hi Free,

Ok, I understand. Very sorry for all your troubles. When it goes wrong, it goes wrong!
If they were mine and three years old, I won't have your patience and will scrap it all.
If that can help, after several years of troubles with a S-530 bank (2011), I have installed Rolls 5000 serie in january for a client. They were perfect from the start and are still going strong. My client is much more happy than he was with the old S-530 and I sleep a lot better. It's just a bit more... expensive, but you won't regret your investment and it will last 3x times longer than a regular L16 (Rolls S-550/Trojan HC or Crown 6CRP525). Finally, it's only a matter of quality and L16 are not so cheap vs their short lifetime.
My company is Solaire Laurentides in Qc.
All the best,
Erik

Freewilley

Well, for $450 Canadian I can add a new 550. I have a new 550 sitting here. So all in, $450 for a new string of  12 volt with 428 amp hours.
And a backup pair that in a pinch can power through a night or day.

I expect it would be about $1500 or more for one series 5000, with 500 amp hour capacity. 

Yes, B would last more than A. But at this point, I think I will give the 550 one more try. Being brand new, I can replace them under warranty in a year or two if they do not work out.

The other thing is that I found a good offgrid tech within an hour of me. I will try the new pair and if they are not working, I will have him in to review my whole system and correct any problems that are causing me grief...that is a better place to spend a grand, I think.

I am looking 3-4 years ahead and thinking lithium will be cheap enough to switch to....we shall see.

thanks a bunch for your advice., and thanks to all who read this thread and ponder my situation!

SolarMusher

Free,
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Erik

Freewilley

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softdown

The inability to realistically swap out 2 volt cells is a great argument for using 6 volt batteries instead of 12 volt batteries. Even better argument for the strategy of using individual 2 volt cells.

I have discarded a lot of 12 volt batteries. They all had five good cells and one bad cell. One bad cell has the potential for absolute catastrophe. I don't know how likely that is but fear is a powerful trump card.

Forklift batteries offer the potential to replace bad cells. That can be pretty tough unless you have the right equipment and the external sides of the 2 volt cells are very clean.

Now why does an individual cell go bad while the rest are fine? I suspect battery manufacturing that is less than ideal. Or very extreme overcharging. In solar, it could be the way the batteries are wired together during installation.