Fast/Large capacity cell tester.

Just John

Solar Addict
I managed to buy an EBC-A40L. I say managed, because apparently I got a bargain price, $173.63 off Aliexpress.

Good luck finding it for that now.


They raised the price and raised shipping by quite a bit each.

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This is a 40 amp charger, and a 40 amp discharger specifically for testing individual cells, not batteries (limited to 5 volts or less).

Internally, it has a 5 volt at 60 amp rated supply. If you do purchase one, be aware it ships with a Chinese power cord rather than a US cord, and has a seal right next to the "only use 220 volt" sign. I had to open it up to figure out there is a VERY TINY window on the bottom where you can switch the internal supply from 220 to 110 (without opening it up).

Pretty darn easy to set up and use. It is an "industrial" device, in other words it is loud. It doesn't get hot, and despite the manual saying it is limited to 35 amps charging, it came setup from the factory to do 40 amps. I think the manual needs updating (and a better translation).

The software that came with it is easy to use.

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So far, not problems doing exactly as advertised, charge and discharge at 40 amps, with data logging and fully automated charge/discharge/charge cycle. Not getting or running hot. I dislike the alligator clips, but other than that, not a lot to dislike about the unit. Voltage accuracy is very good according to my Fluke, start and stop voltages work as expected. Really easy to do a cell a day and leave them at 3.65v ready to assemble into a pack.

If you can find it at a reasonable price, better (and cheaper) than purchasing power supplies and electronic loads separately.
 
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snoobler

Solar Honey Badger
Moderator
It appears the load and voltage circuits are separate, hence the two pairs of alligators.

This is not a concern. The separate voltage sensing circuit eliminates the effects of voltage drop. In fact, in this case, I would prefer alligator clips for the rapid connect/disconnect.
 

Just John

Solar Addict
It appears the load and voltage circuits are separate, hence the two pairs of alligators.
Yes, I'm still not enthusiastic about pushing 40 amps through alligator clamps.
I'm very much aware of the fact it has a separate voltage sense circuit. In the past I've been using Anderson connectors, almost as much work, but much better connection.

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This is not a concern. The separate voltage sensing circuit eliminates the effects of voltage drop. In fact, in this case, I would prefer alligator clips for the rapid connect/disconnect.

Yes, I know what the sense wires and circuit is for. I'm still not a fan of alligator clips, particularly for carrying large currents.
I'm still debating putting in some 50 amp Anderson connectors, obviously the sense wires wouldn't need that. Then I would have to either crimp both wires into one lug/ring terminal, or connect two.

For the time being, I have put a busbar sticking out from each terminal and clamped there. It is making a better connection than I thought it would. Finally got all the parts for a headless NUC, just remote desktop to it and run everything via Wi-Fi despite everything wanting serial or USB connections. Had to get a dummy HDMI plug.
 

Just John

Solar Addict
Just an update since I now have a PC hooked up for data logging (was running some tests manually since my laptop battery wouldn't last long enough, and didn't want to move a full PC into the garage).

Just like @Off-Grid-Garage , I find the software quite easy to use, and wanted to post an example (still playing with settings, like charge cutoff, wait time, etc).


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And finally, the data log (saved as a CSV file, so very easy to manipulate). You can download the software (I added it to the resources section here) and play with the saved file I've attached. Now I have real data to tell people don't charge above 3.4v, and don't discharge below 3.0v.

Typical commodity grade Eve cell, put in 278.8 amp hours, and get back 278.7 amp hours. The claim of 98% efficiency is not an exaggeration (and I've confirmed this with multiple testers).

I have some of the grade A Eve 105 AH cells on order, I'll post some test results from those when I get them.
 

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