JBD 4S 200A BMS

[Just John]

And I'm not convinced the balancing function works well when the cells are a bit out of whack. It is happily balancing all 4 cells now after manually equalizing them a couple of times.

The balancing function works fine, if you top balance first, and charge/discharge on a regular basis. Once they are top balanced, all it needs to do is make up for any difference in self-discharge rates. On the other hand, if you are like Andy and go months at a time between getting to 100%, you are attempting to make up for 30 days or more of difference in a single charge cycle and it doesn't work so well.

The defaults work very well if you regularly charge until cells are above 3.4v (which is really 99% full). The defaults also only bleed energy off when you have the energy to spare (i.e. you are charging). Above 3.4v is when you start to see the imbalance, so for most people, it "just works" and does it well.

 

[JayFC]

This 200a BMS has two temperature sensors. I was thinking of putting one between the center cells and one taped to the outside of cells. Sound good?

Interestingly, reading the specs of CALB cells i purchased. They clearly state they monitor temperature on the metal post of the cell.
That makes so much better sense than putting temp probes anywhere else on the cell. Posts seems to be made out of aluminum and will necessarily be transfering the inner cell temperature better than anywhere else.

 

[pretzel]

Interestingly, reading the specs of CALB cells i purchased. They clearly state they monitor temperature on the metal post of the cell.
That makes so much better sense than putting temp probes anywhere else on the cell. Posts seems to be made out of aluminum and will necessarily be transfering the inner cell temperature better than anywhere else.

Great info, thanks. A ring terminal with the proper wire caliber to fit the sensor would probably work very well for that.
Maybe a little thermal paste + gentle compression to keep it in place.

 

[HRTKD]

Interestingly, reading the specs of CALB cells i purchased. They clearly state they monitor temperature on the metal post of the cell.
That makes so much better sense than putting temp probes anywhere else on the cell. Posts seems to be made out of aluminum and will necessarily be transfering the inner cell temperature better than anywhere else.

I have three temperature sensors on one of my batteries. One on the positive post and the other two located in the center of the battery, in the crease between cells 2 and 3. It's a 4s battery. The temperature difference between what each temperature sensor reports is insignificant. Less than .5°F. So put the sensor where you want. Not all sensors are designed to attach to a battery/cell post.

 

[McDavid403]

Hi Everyone, have had this 200A JBD BMS running on my 4x 280AH Eve lifepo4 batteries for about a week. Top balanced and then have fully charged and discharged one cycle. Cells stayed balance within 0.005v. During charging the BMS balancer kicked in on each of the 4 cells at some point and kept the cells relatively in balance. But now I’m noticing cell 4 is lower then the others and the balancer is kicking in for every cell but cell 4. I checked the balancer lead connection on the cells and re-tightened. But still getting the same result. Anyone experience this? Any ideas? Attaching photo and balancer kicks in for cell 1 which is lower then the others but never kicks in for cell 4. Photos shows a delta of .074 but it has been as been hovering at 0.15

 

[McDavid403]

Hi Everyone, have had this 200A JBD BMS running on my 4x 280AH Eve lifepo4 batteries for about a week. Top balanced and then have fully charged and discharged one cycle. Cells stayed balance within 0.005v. During charging the BMS balancer kicked in on each of the 4 cells at some point and kept the cells relatively in balance. But now I’m noticing cell 4 is lower then the others and the balancer is kicking in for every cell but cell 4. I checked the balancer lead connection on the cells and re-tightened. But still getting the same result. Anyone experience this? Any ideas? Attaching photo and balancer kicks in for cell 1 which is lower then the others but never kicks in for cell 4. Photos shows a delta of .074 but it has been as been hovering at 0.15View attachment 93855

One more thing I noticed. When the cells are below 3.46 - 3.47 the balancer does kick in for cell 4, but it seems once it reaches that threshold it stays there while the other cells continue to charge and balancer kicks in for the other cells.

 

[MisterSandals]

while the other cells continue to charge and balancer kicks in for the other cells.

Can you post a pic of your settings? I dunno, maybe something to be seen there?

 

[OTRwSolar]

. . . . I’m noticing cell 4 is lower then the others and the balancer is kicking in for every cell but cell 4. I checked the balancer lead connection on the cells and re-tightened. But still getting the same result. Anyone experience this? Any ideas? Attaching photo and balancer kicks in for cell 1 which is lower then the others but never kicks in for cell 4. Photos shows a delta of .074 but it has been as been hovering at 0.15

I've watched our 200a JBD balance a number of times. It appears to be a passive balancer, which means it only bleeds current from the cells with the highest voltage. It doesn't move current from one cell to another like an active balancer.

Cell #4 in your pack is .60v - .74v lower than the other 3 cells. Nothing to be gained by bleeding off current from cell #4 since it already has the lowest voltage.

 

[Just John]

Hi Everyone, have had this 200A JBD BMS running on my 4x 280AH Eve lifepo4 batteries for about a week. Top balanced and then have fully charged and discharged one cycle. Cells stayed balance within 0.005v. During charging the BMS balancer kicked in on each of the 4 cells at some point and kept the cells relatively in balance. But now I’m noticing cell 4 is lower then the others and the balancer is kicking in for every cell but cell 4. I checked the balancer lead connection on the cells and re-tightened. But still getting the same result. Anyone experience this? Any ideas? Attaching photo and balancer kicks in for cell 1 which is lower then the others but never kicks in for cell 4. Photos shows a delta of .074 but it has been as been hovering at 0.15View attachment 93855

Depending on the charge rate, when your cells settle to 3.4v, you are 99.9% full. Above 3.4v (again, depending on charging rate and time), don't worry about a voltage differential unless it is very large (like above .1v). People seem very hung up on a few millivolts above 3.4v are seriously wasting their time and stressing over nothing.

 

[McDavid403]

Can you post a pic of your settings? I dunno, maybe something to be seen there?

 

[McDavid403]

Depending on the charge rate, when your cells settle to 3.4v, you are 99.9% full. Above 3.4v (again, depending on charging rate and time), don't worry about a voltage differential unless it is very large (like above .1v). People seem very hung up on a few millivolts above 3.4v are seriously wasting their time and stressing over nothing.

Just odd that the 4 cell won’t charge all the way up like the others. This is where it seems to settle.

 

[MisterSandals]

How high are you intending to charge everyday?

 

[Just John]

Just odd that the 4 cell won’t charge all the way up like the others. This is where it seems to settle.

Just as an FYI, charging (or attempting to charge) to 3.65v per cell is a very bad idea.
That is a voltage you use for capacity testing.

 

[McDavid403]

How high are you intending to charge everyday?

I have it set at 3.5v per cell. I had set it at 3.6 just the one time to see what would happen with that 4th cell.

 

[McDavid403]

Just as an FYI, charging (or attempting to charge) to 3.65v per cell is a very bad idea.
That is a voltage you use for capacity testing.

Thanks! I have the cell full voltage now set at 3.5

 

[bryn]

my order of another 2 bms arrived late last week, so I installed my 3rd 200amp JBD 4S today in my older lithium battery pack,

I’ll keep one as a spare, just incase, I require a replacement down the road and it’s time sensitive.

the newer models came better packed than the last two I ordered, I had designed my battery boxes around the old style, but it was easy to sort it on fusion 360.

The newer style with the recessed lugs are all good, they save a bit of space, but I do like the older style better.

I noticed Andy got a JK4-8S 200amp active Balancer bms that he is currently testing, looking forwards to seeing the review

 

[740GLE]

Have you pushed the 200a rating often?

 

[bryn]

Have you pushed the 200a rating often?

No i haven't, i have 2 x 304ah 12 volt banks that splits the load between each BMS, i went for the 200 amp BMS, incase one BMS failed and i the one remaining bms is still capable of doing 200 amp loads until i sort out the issue.

I restricted my system to draw 200 amps

 

[pretzel]

No i haven't, i have 2 x 304ah 12 volt banks that splits the load between each BMS, i went for the 200 amp BMS, incase one BMS failed and i the one remaining bms is still capable of doing 200 amp loads until i sort out the issue.

I restricted my system to draw 200 amps

Are you running both 200A BMS's actively in parallel at the [P-] outputs?
Or how are you splitting the load? -thx

 

[bryn]

Are you running both 200A BMS's actively in parallel at the [P-] outputs?
Or how are you splitting the load? -thx

Both banks are in parallel, connected by a blue seas 4 way isolating switch, so 1&2 together, off, or each bank running separately.

Both banks have equal length Pos and Neg cables, to allow them to be independent if needed.

I am seeing an extra 2 amp draw on the A battery over the B battery, but i can live with it.