Docan "EV grade 304AH" test results and questions

[SolarTruckCamper]

Hello All,

Yesterday, I received my order of four "A304"s, which is what Docan calls "EV Grade" 304AH EVE cells. Date codes revealed the 4 cells were manufactured on 9/24/22 and 9/25/22.

Without balancing the cells, I hooked up the four cells a JBD BMS:



I then applied a load for about 5 minutes:



I've seen folks test individual cells and find wildly different voltage drops under load when cells are good vs bad. Are the results I'm seeing rendered irrelevant because the cells are wired up into a pack? If not, this looks good, correct?

 

[upnorthandpersonal]

Looks good to me.

 

[RCinFLA]

At 50A you probably have about 10 millivolt drop from bus bar and terminal compression connections between cells.

The raw loaded slump from rested no-load OCV is 1) 68 mV, 2) 70 mV, 3) 68 mV, and 4) 65 mV.

Subtract off 10 mV for bus bars, yields about 58 mV which is pretty good terminal voltage slump range for 50 amps. Also pretty well matched.

I would trust a good DVM reading directly on base of cell's terminals over the BMS readouts.

 

[Alkaline]

Hello All,

Yesterday, I received my order of four "A304"s, which is what Docan calls "EV Grade" 304AH EVE cells. Date codes revealed the 4 cells were manufactured on 9/24/22 and 9/25/22.

Without balancing the cells, I hooked up the four cells a JBD BMS:

View attachment 137736

I then applied a load for about 5 minutes:

View attachment 137737

I've seen folks test individual cells and find wildly different voltage drops under load when cells are good vs bad. Are the results I'm seeing rendered irrelevant because the cells are wired up into a pack? If not, this looks good, correct?

Cool, how do they look like and what setup are you using?

 

[SolarTruckCamper]

Cool, how do they look like and what setup are you using?

The cells look good, no swelling whatsoever. The four cells are wired in series. Using a JBD BMS.

 

[time2roll]

Looks good. Now run the pack up to 14.2 and see what the top balance shows.

 

[SolarTruckCamper]

Looks good. Now run the pack up to 14.2 and see what the top balance shows.

At 14.2 with 17Amps going in, cell voltage difference is 0.017V.