Another top balance, real quick question.

[Gould]

Yes, the multimeter is hooked up to the same terminals that the power supply is, opposite sides of the pack.

 

[John Frum]

Yes, the multimeter is hooked up to the same terminals that the power supply is, opposite sides of the pack.

Cool, terminate the top balance and let the cells rest.
Check the individual cell voltages in the morning to see how much they settled.

 

[John Frum]

Then assemble into a pack with a bms and do a capacity test.

 

[Gould]

Beauty, will do. Thanks!

 

[Bob B]

No such thing as a quick top balance question...

Good to see you had the patience to let it go to completion.

 

[Just John]

So finally at a point where voltage was increase and amperage dropping much quicker. I’ve been sitting here for about 30 minutes now, should I want for 0 amps or call it done? Is it possible that the power supply isn’t accurately putting out 3.65 V and it’s not able to fully saturate the cells?

You can call it done once it drops under an amp. Probably even more. A lot of people have problems getting 10 amps out of their supply due to bad wiring, they are the ones that need to wait. If you wait until one or two amps, it is certainly done if you had been close to 10 amps prior. Those that start out at 3 or 4 amps, best to wait some more (or fix the wiring).

 

[Gould]

No such thing as a quick top balance question...

Good to see you had the patience to let it go to completion.

Lol, isn’t that the truth. I was ready to tear it appetizing and chart up in serial but figured I’d give it one more day.
Truly appreciate everyone’s help!

 

[Gould]

Apologies for the auto correct, can’t seem to edit.

Quick update, 12 hours after shutting down they’re sitting at 3.48V. I’m off this weekend so will leave them in parallel until Sunday then the build finally begins. I have been planning on capacity testing but I don’t have any of my Victron gear in yet. If I test I’ll be stuck charging back up with the power supply. Won’t take nearly as long but still 50 hours’ish.

 

[Gould]

So things settled nicely with all cells sitting at 3.42 and 3.43. I disconnected and reconfigured in series and noticed the bulging has gotten worse. Here is a shot of the most obvious, gap between the cells is 3/16” so roughly 3/32” per cell.
Should I be worried?

 

[ereams65]

So your fixture is not compressing the cells? Bulging is never a good sign, that's for sure, however, there are several threads around here showing bulging and the users are getting along. I, for one, would discharge the cells to a "bottom balance" level, put them in better compression, and then charge them back up again. I would be doing a capacity test while you're discharging, btw.

 

[Gould]

End game is to have them compressed using the “standard” threaded rod and plywood approach. I disconnected them after the top balance to re-configure them in serial.

 

[Gazoo]

So things settled nicely with all cells sitting at 3.42 and 3.43. I disconnected and reconfigured in series and noticed the bulging has gotten worse. Here is a shot of the most obvious, gap between the cells is 3/16” so roughly 3/32” per cell.
Should I be worried?

I would not say your cells are bulged. Normal expansion for EVE cells is 2mm's per cell. And if my conversion is correct that's about how much your cells expanded.

I don't recall if you have a BMS but if you do I would install it and discharge the cells and you should notice the expansion will be less. This is very typical of these cells. They like to breathe when being discharged and charged. Also cells do not do well stored at a high SOC for long and can lose capacity.

There are many threads regarding clamping the cells as I am sure you know. The main thing to know is too much torque can lessen the life of the cells, that's according to EVE. I don't know if it applies to your cells but I would be careful.

 

[Gould]

Okay, that’s what I’ll run with

Cells have been top balanced for about a week which has me concerned now. I’m headed out of town tomorrow and was hoping to deal with the capacity testing when I’m back Monday. I may have to hook them up quick tonight to discharge them slightly before I leave.

 

[Gazoo]

Okay, that’s what I’ll run with

Cells have been top balanced for about a week which has me concerned now. I’m headed out of town tomorrow and was hoping to deal with the capacity testing when I’m back Monday. I may have to hook them up quick tonight to discharge them slightly before I leave.

They don't degrade that fast. I will attach a chart but I don't know how old the chart is and chemistries may have improved since the chart was made. But still...