New 2V 1000AH T-GEL 4pole 12V battery setup. Help, two of the cells swelling .

[sawma1274]

Hello all I'm new here just joined today actually. I started reading some of the threads and learned a few but I cannot find the one which I am actively searching for.
I am writing quite long so just see the photo attachments if you want to get to the point. But I'll explain my problem below anyways.

I currently have six 2V 1000AH T-Gel battery (two pairs of negative and positive poles which confuses me sooo much), a 2000W 12V Solar Inverter and a 12V SMPS charger (at 14.01V no load and 13.68V on load)
[This 12V SMPS charger can deliver charge upto 10Amps and at the back of the panel, there is a toggle switch for Lead acid (labelled 15V) and SMF/TUB (labelled 14V) I am currently using on the SMF/TUB mode. On initial charging it charges at around 10A and then gradually drops to around 2 Amps over time]
Each of my 2V cells/batteries have two negative and two positive poles/terminals. And my whole problem revolves around this issue..
I am assuming that ALL of these (terminals) need not necessarily connected???, but as I am scared of damaging the expensive cells, I have actually bolted all the bus bar connections.
And My last confusion comes from the end poles of the batteries (which have been connected in series to output 12V) as they have a double pole. I plugged one pair of the terminal to the charger and the other pair to the inverter. As I am not confident in my setup I have not started actually using it and just left there to charge for 3 hours. After that the top two cells (where the end terminals were connected - to the inverter and the charger) had started to swell a bit. It is just noticeable. So I immediately halted everything and stopped charging.
I feel that each one unit of the 2V cell battery has different compartment inside?? so as to minimize current losses (or other stuff which are advanced for me).
So now I had connected the top end terminal of the batteries of the same polarity together, One pair of the positive of the same cell to itself and the other negative pair of the same cell or vice versa.
I have also included a photo of the battery. Can anyone please help me? I am quite new to 2V batteries and T-Gel/AGM classes of batteries.

Below are captions in the photo attachments:

Initial setup. The two top-most cells are not linked to their like-pole(terminals)
and the crocodile clips are connected to only one pair and the other pair to the inverter. I think this is a mistake?!

Current setup: Now I have connected both of the like-poles using three 4sq.mm copper wires. A small amount of Acidic- Water seems to leak from the central valve structure.

Foot note: Although the leak has ceased now, and occurred only during the charging.
Also - could it be that the new batteries are defective from the manufacturer or do I need some kind of BMS? I am really lost here. Until any further help these batteries are just a 360Kgs or 794pounds of paper-weight. I dare not touch them right now.
Also I am ordering a proper MPPT solar panel module which has been delayed due to COVID issues.
Thank you for your time. I would really appreciate it.

 

[svetz]

Welcome to the forums!

I'm not familiar with 4 posts on a single battery, but electrolyte leaking out the safety is always a bad sign and swelling a very bad sign. At a guess the voltage was off causing huge currents to flow into them when first connected or they were disconnected as they were damaged. While it's okay for sealed lead acid batteries to be mounted on their side, other types should not be (could be the internal pressure is so high it's forcing the liquid out, which sounds dangerous - last thing you want is for a battery to explode acid all over the place).

Personally, I'd disconnect everything, let the batteries sit for a day, then take them in to get tested.

I'll move this post to the general battery section to see if others can't provide better information.

 

[digitalsteve]

The extra terminals are most likely for convivence of making parallel connections. More than likely they are already paralleled internally. On the other hand it could be that each battery may consist of 2 cells that can be arranged in series for 4v or parallel as you have them for 2v.
To confirm they are separate cells, Remove the parallel connections at the top, then check for voltage on one of the cells. First between the top and bottom terminal (to confirm you meter works) then do it between the diagonal red and black. If zero on the diagonal, they are separate cells, If the readings are the same, then they are paralleled internally and you can use either set.
If they are 2 cells, then in the first photo, you are discharging 1 cell of each battery, while charging the other cell. Then if you paralleled the 2 sets of battery cell you would probably have seen a spark when making the connection. If you attached a charger shortly after making the parallel, one set would already be fully charged and the other somewhat empty. Possibly overcharging the charged cells and causing the bloating. If you leave them in parallel, not connected to a charger or inverter, they will probably self balance. Check the voltage of each cell to confirm, before hooking up to charger or load.
Regarding a BMS: I am not sure...you might search for BMS for Gel Battery.

 

[sawma1274]

Thank you so much for the replies. I have now kind of 'figured out' the whole battery as one whole unit. I have connected them 'End terminals/poles of the battery where effective voltage is 12V' now in parallel (By connecting them with 3x (4x 4sq.mm) Copper core wires [effective area is 3x4x4sq.mm = 48sq.mm] and O-rings (I am not sure what it is called, what it does is that it clips the copper wire to screws/nuts and bolts of the terminals).

"More than likely they are already paralleled internally"

I agree with you here completely. Quoting,
"then do it between the diagonal red and black. If zero on the diagonal, they are separate cells, If the readings are the same, then they are paralleled internally and you can use either set."

I did and you are correct. The diagonal is Zero. Thank you so much it is a very helpful opinion and much regarded truly correct! Quoting,
"Possibly overcharging the charged cells and causing the bloating", You are completely right here also, regardless of any cause for overcharging the cells. Because I think it may in fact be overcharged, maybe because it was the first time off of factory that I had ever charged. Yes it was the first post-factory cycle. Now I am using the battery and coming to more than 20 cycles off, the bloating and noise (soft mild hissing sound at the valves I think) very low dBs but very noticable in very quiet evenings, now have all ceased. I think it was its own way to let some steam from the packaging.

Regarding a BMS: Me too thinks. I am not sure of this... I have tried to research it but not much to read there is. I'm still very fascinated to learn. And most importantly Thanks again! So much valuable information here.

(Bytheway: I now let the batteries literally sit they were hanging before now just look at the photo attachment below. And just DIYing the LEDs just for fun, might remove or change in the future.)