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-   -   G1 vs G2 Leaf batteries and what to verify from the seller (http://www.buggiesgonewild.com/all-things-lithium/153387-g1-vs-g2-leaf-batteries-what-verify-seller.html)

somfas 05-29-2019 02:42 PM

G1 vs G2 Leaf batteries and what to verify from the seller
 
I plan to purchase Leaf batteries for my conversion. I need 10 modules for a 72V system. In prior threads I have seen a few people mention azlithium as a seller, and in general have seen suggestions to buy on ebay. I have an unreturned email into azlithium to see what they can offer (it seems like they are only selling complete systems with BMS and I have decided to go with Zeva for BMS and whatever they provide for a charger, if anything). However, techdirect has responded to me and they can sell me 10 G1 modules.

1) What are the pros and cons of gen 1 vs gen 2 Leaf modules?
2) I assume they won't be able to tell me what year car and what mileage these came from. What "proof" can I ask for that these are good batteries?

Thanks

izzybird 05-29-2019 04:10 PM

Re: G1 vs G2 Leaf batteries and what to verify from the seller
 
The only way to truly verify the condition of used batteries is to test them yourself or you are just going off their word. I have tired first gen modules and they still blow doors on lead batts just in cleanliness and weight savings, I wouldn’t be afraid of them. I believe 2016 and ‘17 30 kwhr modules were rumored to be degrading faster than anticipated, but I’ve also seen it argued that was just a software issue and updates fix the problem. My personal opinion on these used modules is to run them like the Nissan Leaf cab drivers do. Generally always charge to only 80%, usually discharge to only 50% or so, and quick charging in between. They seem to be having pretty good luck with them running hard all day every day. Unless you have the ability to pick and choose a matched set of modules out of a pile of them, your at the sellers mercy.
Or buy a wrecked leaf and have gobs of modules!

bronsonj 05-30-2019 08:20 AM

Re: G1 vs G2 Leaf batteries and what to verify from the seller
 
Sometimes the seller will tell you the capacity, but again that's just their word.

The issue with the early Nissan was a software issue where it over stressed the batteries and so they degraded more quickly. If the Nissan owner didn't fully charge and didn't let the batteries discharge too far then (as Izzy said) the cells will likely be fine. The damage for over charging and over discharging is cumulative and permanent. So it all depends on what their life was before they came to you and you won't have a clue about that unless you test them yourself.

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.

Good luck!

somfas 05-31-2019 12:37 PM

Re: G1 vs G2 Leaf batteries and what to verify from the seller
 
Thanks. So, just ask the capacity? They can accurately test that? And is that all the specs that would be important to get from the seller? Thanks again

bronsonj 06-03-2019 02:17 PM

Re: G1 vs G2 Leaf batteries and what to verify from the seller
 
Capacity *can* be tested, but you have to have a charger/discharger that will tell you the Amp Hours. The seller may not have a charger/discharger that is big enough to handle batteries like this.

Also, a 56 Ah battery tested from 4.2v to 2.5v has less capacity than a 56 Ah battery tested from 4.15v to 3.0v. I've seen it listed both ways on ebay. I've even seen some sellers guarantee at least 80% of original capacity... Meaning they don't have the charger and/or time to test and if you don't have the ability to test it you'll never know and the seller won't have to worry about giving refunds...

somfas 06-03-2019 04:10 PM

Re: G1 vs G2 Leaf batteries and what to verify from the seller
 
Thanks again bronsonj. I’m looking at some from azlithium and techdirect. $980 vs $610 for 10 modules. I feel like azlithium is the better choice but of course they are the most expensive.

DaveTM 06-03-2019 04:45 PM

Re: G1 vs G2 Leaf batteries and what to verify from the seller
 
I purchased my 7 module GEN-1 from azlithium. When they arrived UPS had dropped the package and one battery was damaged. Azlithium replaced it with no issues. I like my pack and I would buy from him again.

FWIW

somfas 06-03-2019 09:34 PM

Re: G1 vs G2 Leaf batteries and what to verify from the seller
 
Thanks DaveTM

bronsonj 06-04-2019 09:02 AM

Re: G1 vs G2 Leaf batteries and what to verify from the seller
 
When I bought my Chevy Volt cells I purchased some from GreenTechAuto and some from TechDirect.

GreenTechAuto was a bit sketchy... I had a couple phone calls with them and it was weird that the phone calls were answered just like it was some guy with a totaled Chevy Volt rather than a business.

TechDirect was a smooth transaction and I only communicated with them via email and had no problems.

I can't say how either would do with a UPS issue.

izzybird 06-04-2019 09:24 AM

Re: G1 vs G2 Leaf batteries and what to verify from the seller
 
That’s a pretty big price difference, I’d take the savings. They’re both peddling the same thing.

DaveTM 06-04-2019 12:07 PM

Re: G1 vs G2 Leaf batteries and what to verify from the seller
 
When I bot my 7 modules I paid $82 per module.

FWIW

somfas 06-05-2019 07:26 AM

Re: G1 vs G2 Leaf batteries and what to verify from the seller
 
Thanks again all, went with techdirect. Now time to figure this all out lol.

Starman97 07-31-2019 10:37 AM

Re: G1 vs G2 Leaf batteries and what to verify from the seller
 
"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 07-31-2019 10:42 AM

Re: G1 vs G2 Leaf batteries and what to verify from the seller
 
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.:mrgreen::lhmo:

Sergio 07-31-2019 11:11 AM

Re: G1 vs G2 Leaf batteries and what to verify from the seller
 
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 07-31-2019 04:20 PM

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

Originally Posted by Sergio (Post 1640460)
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 07-31-2019 04:35 PM

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

Originally Posted by Starman97 (Post 1640542)
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 07-31-2019 05:48 PM

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

Originally Posted by Sergio (Post 1640545)
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.


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