Last week I reported that I’d noticed an anomaly while running my new ZKE EBC-AO5 through repeated tests using the cycle-test feature of its accompanying PC software. I’ve since identified the likely cause, along with a workaround, and I’m expecting a firmware fix soon from the manufacturer.
The problem can be seen in this chart.
The charge phase is supposed to terminate when the current, shown in red, hits 0.12 A. Instead, it terminates at ~0.25A in the first cycle, and at ~0.5A in subsequent cycles.
I realized that the subsequent cycles were also terminating at about 90 minutes, which stood out, because I’d set a 90 minute timer for terminating the discharge phase if the voltage didn’t drop below a threshold first. A check of the raw data showed that the termination happened at ~88 minutes.
The device doesn’t allow a timer to be set during the charging phase, but I hypothesized that the timer from the previous discharge phase was somehow being utilized during the charging phase. I tried shortening and lengthening the discharge timer and found that, as I expected, it had a corresponding impact on the length of the charging cycle.
So, the workaround is to either omit the timer on the discharge phase, or set it to a duration larger than the time required to achieve a full charge for the cell under test. I’ve successfully run dozens of cycles now:
I also reported my findings to ZKE, using their published email address and received a reply thanking me for the report and letting me know that they would have an updated firmware by the end of the month.
I didn’t do much with my ZKE EBC-A05 battery tester last week while I waited for a cheap, small used PC to arrive to run the EB Test software for long-term tests.
The computer came earlier this week, and after getting Windows patched up, I set up a test to run overnight that would cycle between charging to 4.3v and 0.12A, pausing, discharging at 2.4A to 2.75v, waiting 10 minutes for the cell to cool down, and then repeating the cycle.
When I checked on the progress this morning, everything looked good at first glance.
Upon closer inspection though, I noticed that after the first charging cycle proceeded until 4.3v but terminated prematurely, at 0.25A current, and subsequent cycles cut of prematurely, at ~0.5A.
I tried stopping the test and restarting it again, and found that this time, the first charging cycle terminated at 0.5A.
I’ve powercycled the EBC-A05 and started a new testing cycle. So far, so good, the first charging cycle terminated at 0.12A, as desired. We’ll see if that holds for subsequent cycles.
I must say though, the fact that I’ve had this problem once makes me less enthusiastic about this device. I was thinking of buying another 3, so I could run duplicate control and experimental runs of multi-day experiments at a time, but that only makes sense if these things are generally reliable.
I’ve published an initial version of my review and eventual teardown of the ZKE EBC-A05 DC-Electronic Load & Charger. I’ll post updates as I work with it more.
I just published a teardown of the ZH-YU ZB206+ Battery Tester
I recently purchased an Inateck (EC2001L) 120cm USB to Micro B cable that comes with a Lightning adapter for recent Apple iOS devices from Amazon. I picked the cable for its dual-purpose nature, but it is also set apart by its flat profile, which reduces tangles. My plan was to keep it in my bag with a USB powerbank so that I could use the cable to charge the powerbank and iOS devices.
Unfortunately, it isn’t up to the task. First thing I realized is that I missed the fact that it wasn’t Apple MeFi certified. In the past I’ve had trouble with non-MeFi lightning cables leading to slowed charging rates.
The Inateck cable seems to have the same problem. At first I thought it wasn’t allowing the iOS device to properly determine the current delivery capability of the power source, but when I moved the lightning adapter to another Micro B cable, it worked fine, so, the problem must be the resistance of the cable itself.
I did some tests using a multimeter and some USB testing equipment and I found that the cable does, indeed, have high resistance 370 miliOhms or more, leading to a voltage drop of 0.37v at the 1A charging currents used my iPhones, and even more at the 1.5-2A demanded by an iPad. Other cables had less than half the resistance, and correspondingly, less than half the voltage drop.
This cable is fine for data transfer and occasional charging, but it isn’t what you want to use for charging if time or power are precious, because it will take longer than a lower resistance cable.