Do your old (Efest) small IMR batteries hold their charge? (Mostly they do, several tests were done).

Batteries and Chargers Rechargeable Batteries
1

I try to ignore it all the time, and did no hard testing on it, but very often when I check the voltage on one of these batteries that I have had for a few years (red 14500, lila/red 18350, red 16340, V1 or V2) it is down to 3.7 or so Volt while I can’t remember having run them down in a flashlight. So I then recharge them and forget about it.

With brand name 18650’s (Panasonic, Sony etc.) my impression is the opposite: having not used them for a while they are still well over 4.1 V.

Is there information out there on this somewhere? (HKJ does not test for old cells holding their charge), or do you have the same or a different experience?

Edit:
In the meantime this question has turned into a combined test by several people, in which a large number of new and old batteries of various types, age and brands are charged up and left sitting for two months to see how much voltage they lost. At the end all batteries are tested for remaining capacity, and perhaps more tests will be done.

CRX is collecting the data in a large table in post #27.

2

I have a couple of older (red) e-fest 16340’s that do that.I even found one completely discharged. I charged it up at 250 ma, but I dropped to 0 volts only after about a week.

3

They do it to me as well. I have to top off the cells in rotation for my wife often.

4

I have a couple of Efest 16340 V2 from mtnelectronics that have been pretty good. One is ~2 yrs and the other is ~3yrs old.
Just checked one that hasn’t been used in a week or so and its at 4.12V.

Both have been good batteries and haven’t had any problems.

Where did you guys buy your Efest from?

5

Most were bought from efestbattery.com when they were still in business, some from nkon.nl, and some from dutch vape-shops. All are AFAIK reliable shops that sold genuine Efest batteries.

It is not about a week, it is about leaving them alone for a few months. 18650’s hold their charge fine over that period.

6

I see. I will put that one battery (4.12V) away and will try and remember in a few months to check it again for you.

7

Good idea to do it properly, I will put away a couple of different old batteries too and see in two months what is leftover of the charge.

8

Put a small strip of painter’s tape, the easily removable kind, on it with specific info. Make sure it’s not a small drain from the device.

9

Yes, I have a dozen or so of the small efest cells and they all have high self discharge rates. They get worse with age as well.

10

Is that because they’re protected cells?

11

I don’t own any protected cells. The efest IMR chemistry just seems unstable / has a low life cycle. It gives good output but the price is short life apparently.

Overall, I have not been impressed by efest cells personally but I have not tried many of them.

12

I set an alarm for two months from now (Aug 14) to check on that efest 16340 @4.12V which already has been sitting for a week or so. I’ll try and post back here when the time comes.

13

Interested in seeing the results - havig always used AW 18350, I’ve purchased some of the Efest brand for the first time from MntElectronics

14

This is a part of battery reviewing that I’ve felt has been missing. I have a batch of 30q cells that are not holding charge very well compared to cells like Sanyo ga’s.

15

This is the quite random bunch of cells I will test, quite some Efest cells because that was the question of the OP about, and for the rest a variety of sizes, brands, old and new cells. I’m charging them all now, test will start tonight, and I will leave them for two months at room temperature just sitting there. I will only check the voltage every now and then.
You may ask: can he spare this lot of cells for two months without needing them? uuhm, yes to be honest :person_facepalming:

16

there is a 30Q in the test as well as a GA (the Enerpower). I just wonder if a protected cell has any parasitic drain going on, no idea actually :question:

17

lol, looks like the first layer of my spare cell carriers. I have about 16 efest 18350’s that have just been sitting for a few months and they all dropped voltage from between 3.8-4.0V depending on how new they were. They all came off the charger at 4.18-4.2V.

Not totally sure when they were charged but around 2-3 months is a good guess.

18

Started the test. The voltage that the cells have when they come fresh off the charger may already tell part of the story. I measured it with one of those digital led-display voltmeters that I built into a Liitokala 1-bay charger (checked it, it measures correct within 0.01 V), so the battery experiences a tiny load during the measurement. Btw, I used two different chargers for charging the lot of batteries and the Opus charges to a bit higher voltage than the Efest one. Still here are the voltages on day 0 , the battery numbers follow the order in the picture of post #15

1 4.02
2 4.16
3 0 (cell appears dead, or I can’t untrip the protection)
4 4.09
5 4.11
6 4.13
7 4.17
8 4.15
9 4.16
10 4.17
11 4.19
12 4.16
13 4.18
14 4.20
15 4.18
16 4.17
17 4.17
18 4.16
19 4.16
20 4.21
21 4.08
22 4.14
23 4.17
24 4.13
25 4.16

Note that I added two batteries, 24 is an old Kinoko IMR 18350 from Illumination Supply, 25 is an extra Aspire 18350 battery.

When the test is done in two months time I will make a nice table of the numbers.

19

Perhaps people want to join in and check some batteries that I have not included parallel to this test? All it needs is some batteries that you can spare for a while, a voltmeter, a charger and some patience.

20

I have a hg2 I can put aside for two months. If you don’t already have one in your set. I didn’t see one. Also could do a newer 25r, maybe 6-7 cycles on it