EVE INR-4695 Batteries

Well, is it time for a tasty battery review? Meet the 4695-size lithium batteries. I hope you find this interesting.

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These batteries caught my interest more than anything else, mainly because there aren’t many reviews of them, and this is my first time seeing anything like them.



They look very unusual, and they also feel great in the hand. There’s no insulation at all, just a metal can.


For some reason, I found very little information. Some of it turned up on AliExpress, some on the well-known budgetlightforum site, and some unexpectedly on LinkedIn.


There’s a description there too. Here’s the Google translation:


In short, these are some kind of wonder cells, available in two versions: high-capacity and high-current. The high-capacity version is rated at 32.5 Ah, 119 Wh, while the high-current version is rated at 29.7 Ah, 109.5 Wh.
If I understood everything correctly, the stated operating voltage range is 2.8–4.25 V, although I decided to play it safe and charged them to 4.2 V.
The key selling point is their high capacity-to-volume ratio.



The cells look very much like Tesla cells, but Tesla uses 4680 batteries, even though they look identical from the outside.
The LinkedIn link also shows 4680 batteries, but with a clearly different positive terminal.


There are also 4690-size batteries, which look the same from the outside but have a capacity of 26 Ah.


Although the 4690s look similar until you check the negative terminal, and their impedance is about twice as high as that of the cells being reviewed.


This all reminds me of something... I remember what:


They really do look unusual. Plus, with no markings, they’re just plain barrels and nothing more.
There is a QR code and a serial number, though, so it looks like the batteries are genuine.
The negative terminal is flat, while the positive one sticks out slightly. The plastic insulator rotates freely, and the person who brought them over and I came to the conclusion that there’s a safety valve inside.


Apparently, the dimensions are given for the body itself, excluding the protruding positive terminal, which adds 2 mm to the overall length.
The weight is practically identical. I’d guess the second pair is 2 g lighter because they don’t have the stickers I use for labeling and to ensure the thermal camera works correctly. No, I’m kidding, a piece of electrical tape probably doesn’t weigh 2 g, but it does add some weight.


Impedance of all four samples. The specs say no more than 1.5 mΩ for the high-capacity version and 1.1 mΩ for the high-current version. These results are closer to the high-current version.


The first pair of batteries was precharged at 0.5C to 4.2 V, with charging cut off when the current dropped to 1.5 A. Judging by the readings, the batteries initially had about 30% charge.


As always, let’s start with the charging time at 0.5C, which can be considered “universal” for the vast majority of batteries. It may differ for very high-capacity cells, which are sometimes charged at 0.33C, and for high-current cells, which can go as high as 1C.
A full charge took 2 hours 30 minutes at 15 A. The CV phase was moderate and noticeably longer than with LiFePO4.


Next, I tested charging at 1C, which in this case is 30 A. In my opinion, the CV phase already looks pretty bad here; it feels like this current is too high for these cells.
But the thing is, their stated maximum charging currents are 2.6C for the high-capacity version and 4C for the high-current version, which looks even worse.
In other words, if the graph is this drawn out at 1C, it’ll be even worse—much worse—at 2.6C.


Battery case temperature while charging at 15 A and 30 A. You can already see that even 30 A is too much for it. A reminder: charging is the more critical operating mode. It must be done within a specific temperature range, and that range is noticeably narrower for charging than for discharging.


The tests were run at 0.2C, 0.5C, 1C, and 40 A, where C = 30 A. Why? Because at the start, it wasn’t entirely clear what kind of batteries these were: some sources listed them as 30 Ah, others as 32 Ah.

In any case, the first sample delivered almost 35 Ah, comfortably exceeding either rating—32 Ah, and especially 30 Ah.
So, a big plus here.


Temperature at 1C and 40 A.


The second sample showed similar results.


Temperature at 1C and 40 A. In my opinion, around 30 degrees of temperature rise at 40 A is already quite a lot. I’d limit continuous discharge to 0.5C, especially when the batteries are assembled into a pack, or use active cooling.


Checking how closely the characteristics match at 0.2C, 1C, and 40 A. Everything looks fine to me, but the second sample is clearly a little lower in voltage, and the gap depends heavily on the current. Its impedance was also slightly higher, though.


I tested the third and fourth samples at currents of 0.2, 1C, and 40 A, where C was 32 A. That’s clearly more appropriate, since the batteries under review are 32 Ah, not 30 Ah.

The results here show even better consistency in performance, in my opinion, and the measured capacity is virtually identical—which makes sense, since the test conditions differed by less than 10%.


Temperature of the third sample at currents of 32 A and 40 A.


And, accordingly, the fourth sample under the same conditions.


Just to be safe, I measured the residual capacity after discharging at 40 A and letting the battery cool. The spread was relatively large, but the actual value of 266–799 mAh is small, which is good: it means the battery delivered almost all its energy during discharge.



As an extra, I’d like to draw your attention to the rather unusual discharge curve. I noticed it as soon as I got the first graph, and it surprised me a little.
The thing is, the curve is almost linear, with no sharp drop even at the very end. I even thought they might behave like multicomponent LiNiCoMnO2 cells, but when I looked at the results for the 50 Ah battery under test, it turned out they don’t.
Unfortunately, I haven’t reviewed any “ordinary” lithium cells with this capacity, so I can only compare them with the one mentioned above. But the fact that their graphs are clearly different is undeniable.
What does this usually tell us? That they have different chemistry, since discharge curves and chemical processes are closely linked.


Conclusions.
These are definitely interesting batteries. Sure, they struggle with high currents, but they’re more than suitable for building a high-capacity portable power bank or charging station. Compact size, high capacity—well above the rating for this size—and very consistent results. Honestly, it’s hard to find fault with them.
Actually, no—I’ll find fault with one thing. As I understand it, the contacts here are aluminum, which means you’ll need laser or ultrasonic welding. Forget about any kind of spot welder that supposedly supports aluminum right away; that’s nothing more than marketing.

Otherwise, I can definitely recommend them, but only buy them with nickel or steel tabs already welded on.