batteries charging PairA [13.8V+13.9V] & PairB [14.3V+13.3V]

[vas]

following the reconstruction of the battery tray and the general shorting out taking place down there, I now have the 4 service batteries connected and working. System is 24V
I picked the four best (of my 6 batteries, all normal sealed type batteries 180Ah) connected them in pairs and then parallel and system's working.

HOWEVER,
the first pair with the Victron charger on and working show (on a digital handheld multimetre) that they are on 13.8 and 13.9 Volt respectively. Nice matching values and have tested them by leaving them disconnected for a couple of days and they were evenly matched at 12.8V

The other pair though is an odd one. The one battery was showing 13.2V (being left disconnected for charger and loads for two days which I thought was a bit too much!) it's pair was showing 11.something rather after a couple of days off charge.
The high level one was engine starter battery and it's original pair is now showing 6V no matter what (even tried a normal 12V charger connected to it as a standalone, but the bloody charger autodetects I guess a fully charged 6V battery and does bugger all) so is currently on the aft deck to be hauled down and sent for recylcing.

Does the thing makes sense? I'm getting an extra battery to replace this 6V one... Should I pair it to the overperforming one to have a strong pair or is it OK to have such discrepancies?

I know/understand the theory, however I've no experience with so many batteries in odd combos, so any ideas welcomed.

cheers

V.

 

[rafiki_]

Bump. Sorry Vas, not really able to help, but the advice I have had says it is best to change all the batteries in each loop together, otherwise the worst one will pull the new ones down quickly. Others on here will have more expertise.

 

[rbcoomer]

Hi Vas,

Not much direct experience in boats from me either, but with UPS battery banks you do get some odd effects charging in-situ and I'd remove and charge one at a time in order to evaluate health accurately. By charging either in parallel or series you can get distorted results - some will draw more current and can make a connected good battery not get enough charge/appear dud etc. If they've not been used for a while then I'd trickle charge over a long time - perhaps with a low power 12V solar panel etc given all that free energy you have there? I've had 12V car batteries that appeared dud and left a week or two on a solar panel have made a remarkable recovery true DC or high frequency chargers seem to work much better than rectified mains variants in my experience and unless you can charge from the engine, they probably need a long charge.

Regards,

Robin

 

[vas]

thanks guys,

Robin, I've not (yet) got a solar panel and never thought of them being able to slow charge properly a dud battery...
Turned off the Victron, and tomorrow morning I'll do another measurement (only the refrigarator and the 24->12V dropper will be on for these 12h)
We shall see what they show in the morning and probably get a new one and mate it to the overperformer, then get a slow charger for a week on each of the other two and see what's up.


cheers

V.

 

[BartW]

I'm with Rafiki,

if the batt's are +3yo, just go for new ones, then you're sure,

if a battery is broken, it could give 6v instead of 12V, even with a charger,
some chargers are just current sources, and show the voltage from the connected battery cells.

the 13.8V -13.9V pair seems ok, you could give these a try,
but never mix them with new

 

[vas]

update,

went to one of the three shops selling truck/boat/caravan/car batteries here (was recommended by others) and he came over to test the 6 batteries.

The 6V one is dead, and it's pair (as starting batteries) that is showing 14.3+ is also scrap.
A 10.8V one that wont charge any further is also scrap...

This leaves me with the nicely matching pair (13.8V) which is fine and another one slightly less that can be kept as genny starter battery.

Means I need two pairs of batteries as it stands

He recommended a Pb-Ca battery (that is calcium ) and he claimed that they are much better at being left alone, maintain their charge for months (obviously with no load) and they are marginally more expensive compared to the other ones (200euro vs 170euro or so for 160-170Ah ones).
He's installed a couple of them in a sailing yacht 16ys ago and tested them last year and they are still fine. Hard to believe but anyway I'm not going to make any rush decisions there.

So, anyone used calcium batteries before?
any good?
should I use them or go for plain vanilla sealed batteries (NOT gel!)

Mind following the Lozzer thread (iirc) I'm not considering deep discharge batteries, just cranking stuff.

Ah, and he also confirmed that my genny HASN'T got means to charge it's own battery, so need a charger for that as well (maybe a 220V->12V intelligent charger as suggested in another thread) and then I can use this battery for the passerelle as well.

cheers

V.

 

[rafiki_]

Vas, I've not come across lead calcium batteries before. I've just checked my normal supplier, Battery Megastore, but no mention of Pb Ca there either. You are wise to do a bit of research before deciding. Good luck.

 

[abraxus]

I've just bought some batteries from Battery Megastore/Performance Leisure and according to their website both the Alphaline and Varta batteries are sealed calcium.

No idea if they're good as I've only just got them, but they were cheap at less than £90 for the 125ah ones.

 

[davids0865]

I hired a dumper yesterday and just happened to notice as the battery is on display ( and the hire co mentioned it was new) that it had Pb Ca, and the do not dump symbol on the side. I can assure you that this is a dead standard lead acid battery!!

 

[MapisM]

the advice I have had says it is best to change all the batteries in each loop together, otherwise the worst one will pull the new ones down quickly.

I've just seen this thread. +1 on the above.
Actually, I've always been advised (*) to change all the service batteries together, not just each pair.
The reason is that once they are connected (each battery in series with another one to make 24v pairs, and each pair in parallel), they all get charged through the same 24v charger, hence also unbalanced pairs can lead to faster deterioration of the whole bank.
Though I must admit that I never studied the issue in deep detail, 'cause I always changed the whole bank anyway.
Never had problems of abnormally unbalanced batteries so far, in fact...

(*): by a friend of mine who is electronic engineer, not by my batteries supplier...

 

[Keith-i]

Calcium is a very common additive to lead acid batteries these days. Most mid and upper range will have it. Take a look at the Varta or Bosch websites for more info. I believe it helps reduce self discharge but there is a minor side effect which I can't remember.

 

[vas]

thanks all,

seems a bit of pumping up the importance of Ca on these batteries he's selling at a higher price. (fwiw, they were N150 Royal batteries, manufactured by Delkor Corporation)
Also didn't like the fact that he avoided quoting a price for the bog standard sealed acid batteries I have currently installed!

Anyway, do my shopping around Volos and then will check a couple of online shops before I make up my mind.

IF the 10+yrs for PB-CA batteries was real (compared to maybe 3-4yrs for then bog standard ones) then I'd consider them, else I'll get four new identical ones for service, keep the ballanced pair for starter (sorted out the relay in order to start engines from the service bank ) and the best of the rest for the genny start + passerelle.
Means cost could be anywhere between 600=1000euro for 180Ah ones.

cheers

V.

 

[rafiki_]

Vas, with a little digging, it appears that PbCa is pretty much the norm for leisure batteries. I had new starter batts on Rafiki nearly 5 years ago, and they were like new when I sold her. The last ones I bought, a year ago for domestic use were about €115 for 115ah batts.