Another purchase from Dongguan lightning new energy technology co

DerpsyDoodler

Photon Sorcerer
Current dropped to .8a and I disconnected the test. I had the PS voltage set to 3.6. I will let the cell settle for an hour, make note of settled voltage, reconfigure ps voltage to 3.65, reconnect, and top it off. I will then let it settle an hour and check voltage again. I was going to let it sit for a day to make sure it holds, but I think I will skip this. When shipped they measured 3.29 as also measured when received ~45 days later. Not that this couldn’t be falsified. Still, if there are holding problems I think they will make themselves evident (unless someone has something else to say about this).
 

DerpsyDoodler

Photon Sorcerer
here is all the equipment used in this process, no equipment was harmed in the making of this series. 😂
second pic is of my power supply naked.

update on the charging cell: settled to 3.48v and held. Now saturating to 3.63v (slightest adjustment changes too much even with fine knob). When current drops to 0.1 I will disconnect and let settle for an hour, take voltage, and begin capacity test.
 

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DerpsyDoodler

Photon Sorcerer
Cell number one capacity test is close to 265AH and still going. last voltage check at battery terminal was 3.17. I know I’ve lost a fair amount of power to heat, due to crappy leads on the capacity tester. This would be power lost before measurement. l replaced the leads with real copper 12awg wire. The ones that came with were CCA. I should have known better. Regardless of this mistake on my part, the battery is still going to pull the capacity it was sold to me at (272AH).
 

DerpsyDoodler

Photon Sorcerer
ehh, I think the voltage calibration on my capacity tester is off. I believe this run is a bust. I’m gonna have to get a cheapy inverter and hall sensor I can use to power my PS while charging bleh, if I had a bms. This way I can recycle a large portion of the power I charge the batteries and capacity test with. I suppose it should have been an alarm when the voltage was not coinciding with my dmm measurement at the tester input terminal. I didn’t think anything of it. I was just happy I started my first capacity test...lol. I am certain I can calibrate it, but I still want to be recycling the power I am using to charge these batteries. I don’t have solar on this house. I imagine charging a lot of batteries, over and over may get costly on grid.
 
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DerpsyDoodler

Photon Sorcerer
I have the capacity tester LVD shutoff set to 2.5v. It finally kicked. Here are the various measurements:

battery terminal voltage under 15a load: 2.81
capacity tester terminal voltage under 15a load: 2.71
capacity tester display voltage reading: 2.56 @ 15a

Final AH reading: 285.3AH (after having let it restart twice)
total testing time of ~18h:59m

Taking into account everything I’ve said, I feel like regardless of proper calibration, this cell has performed to its capacity. I will shake out these details as I work my way through the next 15 cells, and maybe retest this one once I feel more confident with what I am doing.
 

DerpsyDoodler

Photon Sorcerer
Hmmm, much ado about nothing? I entered into the calibration settings of the capacity tester, checked its current measurement against my dmm measurement at the capacity tester terminals (with 1mOhm current) and it matched. Tested voltage at capacity terminal voltage compared to capacity tester measurement and it matched at 2.79v. However, when increasing current to 5amp or 15a load I see about a 9mV drop for either. Therefore, voltage reading of the capacity tester drops between the tester terminals and its current sensor under load.

what exactly does that mean for my test? Anyone have input here?

I am leaning toward “accurate enough to trust I got what I paid for (or more)”. Second cell is still charging. I’ll hold off on starting its capacity test until I have a better understanding.
 

DerpsyDoodler

Photon Sorcerer
Update:

I was a little tired when I was looking at the numbers. My capacity tester is accurate to within .05v (just like its spec sheet says). So, the test was good enough. I got wonderful capacity. I am holding off on the next capacity test. I want to be able recycle this power or charge from solar for these cycle tests. Considering a plan.
 

DerpsyDoodler

Photon Sorcerer
I’ve completed 2 capacity tests, so far, and both resulted in >280AH (these were billed and sold as 272AH). I‘ve completed charging and resting 4 cells (6 if you include recharging the 2 that were capacity tested). I took resting voltage measurements at 1, 4, 12, and 24h timeframes and found all voltages holding as expected.
 

DerpsyDoodler

Photon Sorcerer
12v BMSs will arrive today. I will be able to assemble these batteries in series, capacity test them, and recharge them using my epever solar controllers and solar panels.

parallel charging these guys to 3.63 now.

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Just John

Photon Sorcerer
Sure! Glad to try and help. Some of the conversations seen on the forum make the process seem more convoluted or nightmarish than it has to be. I think with a little due diligence, the process can go this smoothly for most. Also quick update, I boosted the amp output to about 9.5. All connections still cool to the touch. This PS has plenty of ventilation flowing through it, and I used 10awg wire and ring terminals for the connections. I think it should push 10a fine, but why push it? I’ll be happy when I ramp the voltage up for several cells in series.
I guess I should go ahead and post it, but so far I took the lowest cost 30v, 10a supply I could find on Amazon and tested it (via electronic load) at 10 amps draw, 3.65v, 14.6v, and 30v. Didn't break a sweat or even put out warm air. My load has a limit of 60,000 seconds, so 16.666 hours on each setting. So at least some of the cheap supplies are accurately rated and able to put out full 10 amps pretty much indefinitely. I need a thermal camera, but I did use a temperature probe on the exhaust fan.
 

curiouscarbon

Science Penguin
looking good. the new BMS wires look like finer strands and more flexible than older version (harder wire)

looking forward to hearing about series JBD BMS operation. (y)
 

DerpsyDoodler

Photon Sorcerer
looking good. the new BMS wires look like finer strands and more flexible than older version (harder wire)
they are fine strand and quite flexible, yes. I purchased these directly from jibadai (JBD) off alibaba.
looking forward to hearing about series JBD BMS operation. (y)
I have no intention of series connecting these. I’m not even certain these can be series connected. I will be building 24v packs, but not with these BMS.
 
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DerpsyDoodler

Photon Sorcerer
First capacity test of a 12v pack complete. 283AH. I am quite happy. Started capacity test of another 12v pack. Hopefully tomorrow or Saturday I can test my solar equipment by recharging the first pack. Picture shows me putting some juice in, but just enough to keep it comfortably over the 2.5 per cell mark.

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