G1 vs G2 Leaf batteries and what to verify from the seller

[DaveTM]

When I bot my 7 modules I paid $82 per module.

FWIW

[somfas]

Thanks again all, went with techdirect. Now time to figure this all out lol.

[Starman97]

"I charge my lith cells to 4.12vpc and discharge to 3.25vpc. My parameters are more conservative than many on here but it should help my cells have a long happy life."

That charge seems high, the Leaf Gen2 cells are Li-Ion, correct?
The specs say 4.1v max and and 2.50v min(really?) and that Nissan only charges to 4.00
I was going to go with 56V on the charger so that an out of balance cell should never get to 4.10 and
on the low side, set the min to 3.85 on the BMS cutout trigger,
but that will go to the Alltrax 1/2 speed reverse pin to allow a 'limp home'
and set the Alltrax to 3.75V (52.5 or 52V) to prevent any weak out of balance cell from getting to 3.65
My goal is no more than 85% charge and no lower than 85% discharge.
This is a 14 battery 120ah Gen2 pack. So at the lowest level it's 4P14S (internal cells), full rated is 33ah/Cell
And we have a Chargery C10325-BMS16T with 1.6A shunt balancing enabled in all phases.
(using this chart : https://evbatterycenter.com/HAC4/ima...60Ah_small.jpg)

[DaveTM]

On my Gen 1 leaf pack, my max charge per cell is 4.1 and my LV cutoff is set at 3.14 per cell while my "balance voltage" is set at 4.08 per cell.

Your milage may vary.

[Sergio]

Starman97, You may want to check the specs on the leaf batteries again, maximum voltage limit is 4.2v (stay around 4.1v or less) and 3.85v too high for cuttoff, 3.65v is a more reasonable value as it is the beginning of the discharge "knee".

For maximum life maintaining a lower upper voltage is way more important than the minimum voltage (within reason).

Also, if You have an Alltrax Controller the reverse input is not a good limp mode since it cannot prevent the pack voltage from dropping, you can do a limp mode automatically by setting the "under Voltage cutoff" slightly higher than your minimum pack voltage (min cutoff x number of cells in series).

That will cause the controller to automatically reduce the current and provide a "limp mode" in order to prevent the pack voltage from dropping below the set target voltage.

Accordingly, set the "max voltage cuttoff" slightly less than your maximum pack voltage (not to be confused with charging voltage which should be lower than the max voltage) to allow headroom for Regen brake current.

That will also cause the Controller to limit the Regen current automatically to prevent the pack voltage from going higher than the set voltage.

[Starman97]

Originally Posted by Sergio

Starman97, You may want to check the specs on the leaf batteries again, maximum voltage limit is 4.2v (stay around 4.1v or less) and 3.85v too high for cuttoff, 3.65v is a more reasonable value as it is the beginning of the discharge "knee".

For maximum life maintaining a lower upper voltage is way more important than the minimum voltage (within reason).

Also, if You have an Alltrax Controller the reverse input is not a good limp mode since it cannot prevent the pack voltage from dropping, you can do a limp mode automatically by setting the "under Voltage cutoff" slightly higher than your minimum pack voltage (min cutoff x number of cells in series).

That will cause the controller to automatically reduce the current and provide a "limp mode" in order to prevent the pack voltage from dropping below the set target voltage.

Accordingly, set the "max voltage cuttoff" slightly less than your maximum pack voltage (not to be confused with charging voltage which should be lower than the max voltage) to allow headroom for Regen brake current.

That will also cause the Controller to limit the Regen current automatically to prevent the pack voltage from going higher than the set voltage.

Thanks for the info, I did not know the AXE4834 (Series wound DC controller) could do a reduced current mode, been a while since I've run the old setup app on it. Regen's not a problem with Series motor

We still have a timing problem, motor's much faster in reverse and no connection to 1/2speed, suspect it's the default brush direction is wrong for this Cushman that has a belt drive from the motor to the differential pinion. It'd be fine if the motor was splined to the pinion like most.

[Sergio]

Originally Posted by Starman97

Thanks for the info, I did not know the AXE4834 (Series wound DC controller) could do a reduced current mode, been a while since I've run the old setup app on it. Regen's not a problem with Series motor

We still have a timing problem, motor's much faster in reverse and no connection to 1/2speed, suspect it's the default brush direction is wrong for this Cushman that has a belt drive from the motor to the differential pinion. It'd be fine if the motor was splined to the pinion like most.

My fault, I assumed we were talking about the newer Alltrax XCT (sepex).

The old AXE controller firmware likely does not have the same capabilities as the newer ones with much faster microprocessors.

How did the original cushman Controller reduced the speed for reverse?

[Starman97]

Originally Posted by Sergio

My fault, I assumed we were talking about the newer Alltrax XCT (sepex).

The old AXE controller firmware likely does not have the same capabilities as the newer ones with much faster microprocessors.

How did the original cushman Controller reduced the speed for reverse?

Did not have it, this was an old unit, still had the rusty air power resistors.
The field reverser does not have microswitches. My Ez-Go from '78 does, but it was for a beeper only.

I'll have to run the AXE util and see what it can do, thought that would be a good 2 level safety and not need a big cutout contactor, although I could break the power control for the AXE contactor with a control signal from the BMS16T.