Sanyo UR14500AC 740mAh batteries from a teardown

Another batch of batteries, and this time they’re also Sanyo, also salvaged from disassembled packs, but in the more compact 14500 size.
The results are pretty good too, which is only to be expected from branded cells.

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As last time, I bought the batteries from Nkon, and they were cheap again because these are cells salvaged from a disassembled battery pack. Personally, though, I find it unusual to use packs made from 18500 cells, let alone 14500s.

I got 20 from a friend for the front panels of radios and maybe something else. Some are already charging, and the rest are in the photo.
I’ll test them all later, though I can already share stats for some of them today.


I couldn’t find the original datasheet, but I did learn that these are equivalent to the UR14500P batteries from the same manufacturer.
The brief specs were enough for me, though.


The color is red, and the positive terminal is flat and protrudes slightly beyond the casing. The 18500s were the same. These batteries seem to have a lot in common with those, including the stated maximum continuous current of 2C.


There’s a matrix code, not only under the heat-shrink wrap but also on the negative terminal. There’s also a coded date marking (presumably), but it clearly differs from the versions I’ve seen before, so I think I was wrong about the 18500s too.
One of the batteries had no signs of welding on the positive terminal. And, by the way, the tape residue here hasn’t been ground off.


Dimensions and weight.


The test was also performed using an EBC-A20 load. At such low currents, it has quite a large measurement error, especially during charging, but unfortunately I can’t use another load for now.

A “conditioning” cycle; as with the previous cells, the initial charge was about 60%.


While preparing the second battery, I had to restart the load, and the stats from the first cycle were lost.


The specified charging current is 0.53 A, or about 0.7C. Charging takes an hour and a half at this rate, which seems perfectly reasonable to me.


For the sake of experiment, I tested charging at 1C, and it turned out that the batteries perform very well even at this rate.


The datasheet specifies a maximum continuous discharge current of 1.52 A. Perhaps the manufacturer used 760 mAh as the C rating; I tested based on the capacity printed on the cells, i.e. C = 740 mAh, but also expanded the test to include 0.2, 0.5, 1, 2, and even 3C.

No issues at the rated discharge rates, but at 3C the voltage clearly sagged, although the battery performed reasonably well overall.


The temperature, on the other hand, was excellent at both 2C and 3C.


The second cell behaved similarly.


The same goes for the temperature.


The consistency test showed a close match between the results, but at 3C one battery behaved somewhat unusually, taking longer to finish discharging right at the end.


Battery impedance as received, after “conditioning,” and at the end. The resistance is only slightly higher than that of the more powerful 18500s I tested earlier.


As an extra, I ran a shortened test on eight more cells, charging and discharging them at 1C.


The test results above are shown as screenshots, but I think this simplified format is more convenient. They look pretty good to me.
1-739
2-737
3-736
4-727
5-731
6-731
7-736
8-721
9-734
10-731

Conclusions.
I didn’t expect anything to go wrong, really. They’re decent batteries, and when it comes to value for money, they’ll probably beat just about any Chinese equivalent hands down, so I definitely recommend them.

That’s about it for now. Good luck, everyone, and may the skies be peaceful.