diy solar

diy solar

Bloated cell extreme heat when trying to equilize

NewRuins

NewRuins

New Member
Joined
Aug 6, 2020
Messages
22
Location
Oaxaca Mexico
Have a bloated cell with 2.6v in the bank
Connected in parallel with a good cell.
Generated extreme heat at the terminals Disconnected quickly and bloated battery now at 1.9V

Its fully dead, right?

Part two:
I have some good 400ah cells. Could i put one in its place to hobble that system along til i get new cell?
 
NewRuins said:
Have a bloated cell with 2.6v in the bank
Connected in parallel with a good cell.
Generated extreme heat at the terminals Disconnected quickly and bloated battery now at 1.9V

Its fully dead, right?

Part two:
I have some good 400ah cells. Could i put one in its place to hobble that system along til i get new cell?
Click to expand...
I am trying to understand why you would have a bad cell in parallel with a good cell. I also question the 2.6vDC in bank.

Perhaps a language translation issue. Typically battery cells are connected up in Series to increase voltage up to a total such as 12vDC (nom) or higher. At that point the battery might be paralleled with another battery to increase total capacity.

A dead cell that is paralleled with a fully charged cell is going to create a high current flow that indeed would heat up your terminals.

On your second question about using a 400ah cell as a bad cell replacement. It would help to know how close of ah we are talking about. The biggest problem with not matching ah would be a unbalanced battery for charging discharging. It likely would not be a practical thing but I do not have enough experience to state it as a fact.
 
NewRuins said:
Have a bloated cell with 2.6v in the bank
Connected in parallel with a good cell.
Generated extreme heat at the terminals Disconnected quickly and bloated battery now at 1.9V

Its fully dead, right?

Part two:
I have some good 400ah cells. Could i put one in its place to hobble that system along til i get new cell?
Click to expand...

3 years old bank is 16 x 3.2V lifepo4 500ah. connected in series to make a 48v system.

One cell is bloated and had 2.6V, so i took the bank half apart and connected that battery with another battery in parallel to try and see of it would equalize.
 
Last edited:
NewRuins said:
3 years old bank is 16 x 3.2V lifepo4 connected in series to make a 48v system.

One cell is bloated and had 2.6V, so i took the bank half apart and connected that battery with another battery in parallel to try and see of it would equalize.
Click to expand...
2 good cells, but of different voltage, will equalize overtime when in parallel. A bad cell is a continuing load on the good cell and eventually you end up with 2 bad cells.
 
Thanks for all the replies.

This Cell is dead. And the system is now down.
We have paying guests coming in a few days expecting to stay at a place with power.

New cells from china would be months away. I am way out in the middle of nowhere mexico.

I have 2 good 400ah cells. This dead system is 500ah. Roughly the same physical size. So should fit into the bank.
Is there a position in the bank where it would have less impact? Like toward the negative end of the bank.. doesnt seam logical.. but never know. This dead cell was more towards the positive end of the 16 cells
 
Sounds like a question for @Steve_S.

Necessity sometimes dictate unusual arrangements. If you do go the route of wiring in the 400ah cells I would suggest dropping your bulk/boost charge voltage down to ~56vDC. No need to push the charge level.
 
Assuming you need full capacity I would parallel the 400s and patch them into the space where the dead 500 was removed. A single 400 of course will reduce capacity by at least 20%.
 
hwy17 said:
500ah cells? Are these winston thundersky?

Doesn't matter where you put the smaller cell. Same effect in any position.
Click to expand...
The 500ah are some black ones with no name..
The 400ah are the winston. I have another system with those. So far no problems. Are there bad news going around on the yellow winstons?
 
If you replace a 500AH with a 400AH that pack instantly becomes 400AH because the smaller cell rules.
This is NOT optimal, but for an emergency short time frame it's ok. DO correct your EndAmps/Tailcurrent to reflect 400AH.
Tailcurrent for that would be 20A.

There are presently no issues I have heard of about Winston...

MATT was quite correct, never put a dead cell in parallel with a good one, you will get 2 dead quickly.
 
I love this forum. You guys are great.
Sometimes i feel like i have no one talk to about this kind of stuff. Prolly because i live alone in the jungle.

Will post a pic of the Frankenstein setup.
 
NewRuins said:
I love this forum. You guys are great.
Sometimes i feel like i have no one talk to about this kind of stuff. Prolly because i live alone in the jungle.

Will post a pic of the Frankenstein setup.
Click to expand...
You may live deep in the Mexican Jungle... I'm deep in the Northern Arboral Forests (NE Ontario Canada) but we all get to talk.. Members here from Australia to Zambia and many points in between. Quite Global !
 
NewRuins said:
3 years old bank is 16 x 3.2V lifepo4 500ah. connected in series to make a 48v system.

One cell is bloated and had 2.6V, so i took the bank half apart and connected that battery with another battery in parallel to try and see of it would equalize.
Click to expand...
did you connect a 3.2 volt cell to your 2.6 cell to equalize it?
If so it's hot because it's getting like 1000 amps into it or something..
 
You must log in or register to reply here.

Similar threads

Philtao
Single cell voltage drop for no apparent reason
2
Replies
23
Views
1K
Marinepower
M
S
Part 2: LFP Top-Balancing in the context of BMS settings
Replies
4
Views
621
shvm
S
S
GUIDE to properly Top-Balance and Charge a LFP Battery: Part 1
11 12 13
Replies
258
Views
13K
Helles
H
jimf909
EG4 Chargeverter: throttle output due to heat? (new title)
2 3
Replies
43
Views
2K
THERED117
THERED117
KevinC_63559
Good vs. bad BMS?
Replies
6
Views
573
sunshine_eggo
sunshine_eggo
Back
Top