[john61ct]

Cells should be 100% isolated in storage, most especially from their BMS.

Don't get your hopes up but

A super slow baby trickle a few 0.X V higher than they are at 0.1C rate or lower

once past 3.2Vpc get them all the way to 3.45Vpc

do what you have to do to balance, without going over 3.5Vpc

never letting current rate going too high, watching cell temperatures

If they look OK, cycle 3-6 times like that, between say 3.1Vpc as zero and 3.5Vpc as Full

Then try cap testing.

 

[john61ct]

Thank you
I am using an RC charger to control voltage and amperage of charge. So set charger no higher than 3.5 at say 10 amps
(.1C would be 18 Amps). Once I got to 2.5 volts, I have been charging first to 3.4 for 2+ hours now at 3.5v amperage is already tailing down below 10 amps with no detectable heating of cell at all.

Sorry I was not more clear.

Charge TO 3.45Vpc and STOP is 100%, CV only

No CV Absorb stage is needed, no point just hurts longevity (if cells were good)

Holding at 3.5Vpc is only for "if needed" for the hardware you are using for balancing.

With a good pack, needed maybe a few times in daily usage cycling.

 

[john61ct]

Charge Ah is irrelevant.

Cap test is discharging after charging using their spec sheet maxV, holding to 0.01C endAmps

at a very low C-rate say 0.05C,

going down to the spec sheet minV

in order to truly compare to nameplate

Personally I think 170Ah is a "good enough" but it's great to get exact benchmarks and track declining SoH% every 300 cycles or whatever.

when charged to 3.5 they both settle at 3.34 volts after 12 hours. both cells stayed stone cold throughout the process.

That is your "healthy 100% Full" definition for normal cycling.

 

[john61ct]

the Icharger short cycle time?

I did not understand any of that, cannot see mAh being relevant on a 170Ah scale

What do you think on Internal Resistance?

I think it is very difficult to measure properly, even comparative benchmarks from one session to the next. All the variables must be held constant, lab level equipment etc. Rick Distler aka rampman's ESR meter (V2) Lipo ESR Meter Mark II, designed by Wayne Giles

available from HobbyKing, also from RampMan direct

and RC Battery (Liperior Lipos)

Lipo ESR Meter Mark II

The original ESR Meter has been the de facto standard for judging the quality of lithium battery packs. With the new Mark II model, it is even better with 25 preset pack sizes (user configurable) and 1-6 cells displayed on one common display screen and fits comfortably in your hands with simple...

rcbattery.com

Is a 20 amp draw pulling voltage down below 3.1 thus stopping the discharge cycle sound like a battery with decent capacity

20A is only 0.12C so ESIR should not be an issue.

At that rate constant current draw from Full should last 7+ hours if they are actually 170Ah

There really isn't much Ah capacity left between 3.1V and whatever spec min V is.

 

[john61ct]

Aha I'd missed that, sorry and thanks.

Both Mark and Rick are pretty active there in RCGroups, start a thread and ask them for advice