New Old Stock 50Ah Power Curves.. These look good?

[CheezWiz]

So I picked up some "used" prismatic cells and ran them through my battery testing rig.
Voltage seems a bit low, but they are holding out to 50Ah, except for one cell.
Running 1c curves now and they are about the same curve at around 3V. Going to test them at 2C next.

1/2 C ^^^^^

https://imgur.com/a/dcxvATr

 

[b.james]

These ae some factory graphs for 180 Ah cells charge and discharge.

 

[CheezWiz]

My workbench and test rig.. Same bench that @Will Prowse just got for his new house! lol

https://imgur.com/a/XX4ZW6q

Just finished testing 16 of these batteries and all tested in excess of 50Ah @ 50 amps..
I got one that had a low voltage and the seller is sending two as a replacement.

I'm running some 1C curves on Headways from Batteryhookup now.

https://imgur.com/a/qXd93LP

 

[grizzzman]

Are these cells from Lion Energy?

 

[CheezWiz]

Are these cells from Lion Energy?

Yes they are.

 

[grizzzman]

Thought so. I grabbed their 2P4S 100AH packs with interconnects. Shipping is free that way. ( Not that that really mattered,30 miles from their business) What test equipment/software are you using?

 

[CheezWiz]

I have a CBA4 Pro with one amplifier:

Computerized Battery Analyzer - West Mountain Radio

The CBA is much more than a simple battery voltage tester or a battery load tester. Unlike a simple load tester the CBA will test virtually any type or size of battery, any chemistry, any number of cells up to 100V. For the first time and for a reasonable price, anyone can do scientific tests of...

www.westmountainradio.com

Yeah, I got two of those packs as well. You can see one in my workbench pic.
They are a bit low in voltage at 1C and at 2C, even lower but they hold out past 50Ah. I have scoured the net for other independent tests of similar cells and found very similar curves. Even the Headways are similar. So I don't think there's anything wrong with them, I think it is just the nature of these cells.

 

[grizzzman]

Ya seems like they last a long time below 3 volts, like the flat is just on the lower end. KC7HOX here.

 

[CheezWiz]

Ya seems like they last a long time below 3 volts, like the flat is just on the lower end. KC7HOX here.

Cool, KD4LYO here, how did you pick up that I'm a ham too? Are there a bunch of us on here? The Headways are for a portable solar setup I'm putting together for HF QRP operation.

 

[grizzzman]

Ahh hmmm A. Your bench B. your choice in battery tester C. my guts said so. Oh your the first one here that I have met.

 

[b.james]

VK4AAZ Howdy Sirs

 

[grizzzman]

VK4AAZ Howdy Sirs

Hi! Is it hot in Aussie land?

 

[CheezWiz]

Man, the spiders! Whenever I meet a cousin from Down Under, I ask about the spiders.
Those suckers are SCARY in Australia. You cant have small dogs down there! lol

 

[grizzzman]

Did you run temps during discharging the 50AH cells? I would be real entrusted in the results.(I run a low speed 120mm fan during use)

 

[CheezWiz]

Did you run temps during discharging the 50AH cells? I would be real entrusted in the results.(I run a low speed 120mm fan during use)

You are in luck. I'm running those now.

 

[grizzzman]

Man you have all the toys ?

 

[grizzzman]

From that pic it appears that the heat generated by the cables are backheating the pos and neg cells. That could explain cell drift that I have seen.

 

[CheezWiz]

Haha, yeah I chose toys over kids! Lol
That's the crappiest Android flir they make. I don't recommend it. I have problems getting it to work with the app constantly.

I have some 6 gauge wires on order. Those would be a 9 gauge if there were such a thing maybe a bit closer to 8 than 10. I've only ever messed with RC batteries and never needed anything heavier. The wires aren't getting very warm. The battery is about 8 over ambient temp. I will run a curve with the new wires to see if it makes a voltage or temp difference but I'm skeptical that at the length it will. We'll see though. That cable is clamped and soldered at both ends so it has the minimal resistance possible.
But I am curious to see.

How high of a current do you run your Lion packs?

 

[grizzzman]

Well not that high. 120amps with the microwave. 55 amps when i brew coffee that s it with the CG2 load sharing at 21 amps

 

[CheezWiz]

OK, so you are running them 4S2P then? For no more than 60 amps per string? Yeah, they will last you a long time!
So here are those 1C curves with temps:

BATT01: Description: 1 LiFePO4 cell, 50.0 Ah @ 50.00A Started At: 9/28/2019 10:01 AM Discharge Rate: 50.00 A Starting Voltage: 3.40 V Ending Voltage: 2.50 V Internal Resistance: 0.01 Ohms Total Time (hh:mm:ss): 01:01:18 Tested Capacity: 51.048 Ah
BATT02: Description: 1 LiFePO4 cell, 50.0 Ah @ 50.00A Started At: 9/28/2019 11:23 AM Discharge Rate: 50.00 A Starting Voltage: 3.53 V Ending Voltage: 2.50 V Internal Resistance: 0.01 Ohms Total Time (hh:mm:ss): 01:01:28 Tested Capacity: 51.188 Ah
BATT03: Description: 1 LiFePO4 cell, 50.0 Ah @ 50.00A Started At: 9/28/2019 12:29 PM Discharge Rate: 50.00 A Starting Voltage: 3.49 V Ending Voltage: 2.50 V Internal Resistance: 0.01 Ohms Total Time (hh:mm:ss): 01:01:28 Tested Capacity: 51.204 Ah
BATT04: Description: 1 LiFePO4 cell, 50.0 Ah @ 50.00A Started At: 9/28/2019 2:51 PM Discharge Rate: 50.00 A Starting Voltage: 3.50 V Ending Voltage: 2.50 V Internal Resistance: 0.01 Ohms Total Time (hh:mm:ss): 01:01:57 Tested Capacity: 51.607 Ah
BATT05: Description: 1 LiFePO4 cell, 50.0 Ah @ 50.00A Started At: 9/28/2019 6:07 PM Discharge Rate: 50.00 A Starting Voltage: 3.53 V Ending Voltage: 2.50 V Internal Resistance: 0.01 Ohms Total Time (hh:mm:ss): 01:01:43 Tested Capacity: 51.396 Ah
BATT06: Description: 1 LiFePO4 cell, 50.0 Ah @ 50.00A Started At: 9/28/2019 7:24 PM Discharge Rate: 50.00 A Starting Voltage: 3.36 V Ending Voltage: 2.50 V Internal Resistance: 0.01 Ohms Total Time (hh:mm:ss): 01:02:39 Tested Capacity: 52.180 Ah
BATT07: Description: 1 LiFePO4 cell, 50.0 Ah @ 50.00A Started At: 9/28/2019 9:20 PM Discharge Rate: 50.00 A Starting Voltage: 3.35 V Ending Voltage: 2.50 V Internal Resistance: 0.01 Ohms Total Time (hh:mm:ss): 01:02:15 Tested Capacity: 51.842 Ah
BATT08: Description: 1 LiFePO4 cell, 50.0 Ah @ 50.00A Started At: 9/29/2019 1:12 AM Discharge Rate: 50.00 A Starting Voltage: 3.46 V Ending Voltage: 2.50 V Internal Resistance: 0.01 Ohms Total Time (hh:mm:ss): 01:02:16 Tested Capacity: 51.869 Ah