Samsung 30Q warm when charging 1.5A

Batteries and Chargers Rechargeable Batteries
1

Hi all,

I’ve googled but can’t find any info.

I bought some 30Q cells from Banggood a few years ago, when I recieved them I wasn’t sure they were genuine so relegated them for backup duties.

I’m doing some capacity tests to see what they’re like as I have an intended use for them now.

Using Vapcell S4 Plus V2.0, ‘Cap Test’ 1500mA charge, it’s discharging at c.900ma.

The cells feel rather warm, I’m not used to cells feeling warm (maybe a few degrees above ambient at most). The charger says it’s 52C, but this is clearly wrong as it doesn’t feel as hot as 52C…

Does anyone have any reassuring words or is this just classic “fake 30Q cell” symptoms?

2

So what is the capacity? Charging at 0.5 C should not get hot, maybe slightly warm.

3

Charge current was 1.5A, I’ve not charged this fast before, usually use 1A.

First cell that’s finished (I think I cap tested once a while ago, or charged it, or something which resulted in higher voltage than the others) gives 3213mAh, notoriously unreliable internal resistance is 42mOhm.

4

1.5 A is rather high.
Are you in a hurry or just impatient? :wink:
I’d settle for 750mA.

5

The 30Q datasheet says that standard charge is 1.5A and rapid charge 4A so I don’t think 1.5A should be causing the heat issue. I’ve charged a number of my 30Q’s at > 1A and they never got warmer than other cells charged at lower currents.

6

Oh, okay.
Then maybe OP’s 30Q cells have degraded a bit.
Not clear how warm ‘rather warm’ is, though.

7

During my early days in this hobby, I remember just using cells from laptop batt packs.

Using my first charger, the Pila IBC, which charges at a measly, by today’s chargers, .6A, but it heated a well-worn, enormously high IR, I now know, genuine Sanyo blue top 18650.

Good thing I was around at that time, as the cell got dangerously hot.

Getting a dedicated IR tester is a must for members who have suspected unhealthy cells.

Like this:

Btw, charging a 30Q at 3A hardly gets it fairly warm at all, as it’s only 1C.

8

That’s a good question! According to some Google results I read batteries shouldn’t get over 140F (60C for non-USA types :partying_face: ), but that seems rather hot to me. My rule of thumb is that if it feels hot and I have even a second’s doubt then I get rid of battery, which I’ve done a few times. The problem is of course that one has to be paying attention to the battery when it’s charging, especially since the temperature will drop as the charger reduces the current.

That’s one of the reasons why I don’t charge batteries inside of flashlights; I can’t tell if the battery is getting hot or something else seems off.

9

Yup, datasheet info is precisely why I’m slightly concerned, hard to tell actual temperature, without a thermometer, but I’d say my hand scale is “freezing, cold, cool, ambient, slightly warm, warm (cosy warmth, like consumer electronics power supplies), hot (side of a mug of coffee, short finger contact tolerable), very hot (more than a short, light touch is painful).

The warmest cell was warm.

I will try a known genuine 30Q (albeit newer in age), and report back.

10

Results from the cap testing on first 4 cells-
3213mAh, 42mR
3336mAh, 51mR
3306mAh, 32mR
3277mAh, 53mR

Still early days with this charger for me, I find setting the discharge/refresh currents is not that clear, the first cell above had 1.5A charge rate, 1A discharge, the others seemed to do 1A in and 0.5A discharge…

With the 3 remaining suspect 30Q’s currently doing cap tests (where is the last cell from my original batch of 8? :person_facepalming: :question: ), I’ve measured the temperature of the cells.

I used an adhesive strip of post-it note to hold down the thermocouple of my DMM, with a tiny blob of heat transfer compound on the surface of the 18605. I gently pressed the whole lot down with a folded piece of tissue, so my finger wasn’t acting as a heatsink. My DMM is not calibrated.

Results:
indicated T°C Measured T°C
53 39
40 29
32 24

The discrepancy is not linear, the lowest temperature cell has a difference between S4+ indicated and measured of –7C; highest cell is –16C.

I don’t know if this is poor calibration, or whether the charger is showing (estimated) cell core temperatures, which would require Vapcell engineers to have worked out a rough correlation between the core temperature and surface temperature…?

Edit to add: Threw the numbers into Excel, calc’d equation is: Measured temp = (0.59*S4 Temp)+5.54

Also edit to add: Running a capacity test on a 30Q from reliable supplier 18650.uk, 1.5A charge, 1A discharge, cell currently reads 57C on the S4+, so I assume this temperature rise is normal at these currents.

11

I recently saw specs I think it was possibly from the recent mooch molicel thread. It said max 10°C above ambient. You should have a rest after discharge so the cell is starting at ambient. Starting at 15°C is probably better than 25C. If you’ve got four cells lined up together in a charger that’s not cool. Some chargers are going to add more heat than others. Air flow is good.

12

Yes, agree cells best kept cool. I usually charge 18650s at 1A; I just wanted to do a faster cap test on them and it not take 10+hours! eg.1hr to charge, 6hr discharge, 3hr to charge again.

13

Am I the only one who is confused by the fact that your tests show more than 3300 A / h, from multi-year Samsung 30Q, which are initially not capable of this?

14

Either: fakes, or the charger reports inaccurate values. The S4+ quite highly regarded though…

15

But that’s probably the charging energy rather than the discharge capacity?

16

I believe the S4+ reports discharged energy to 2.6V after a full charge. The ‘genuine’ 30Q has just finished and shows 2930mAh.

Last 3 2-year old Banggood 30Qs just finished:
3263, 59mR
3293, 57mR
3273, 70mR

17

Might be some rewrapped cheaper LGs or something — do you have a way to check amperage draw of a flashlight (clamp meter) —- charge the original and the ?? cells fully — then use a fet based light and measure amp draw —- that should give you a pretty good idea if they’re real

18

Discharging any cell above 500mah in the vapcell is gonna get >50°C. Look at HJK’s review of the vapcell S4+, every cell is around or above 50°C under thermal imaging under discharge. It’s not the battery getting hot on its own, it’s mostly the charger getting hot and the charger heating the battery. Spin the cell around and feel how much hotter it is on the bottom where it meets the charger than it is up top. And the temp sensor will always be off because the guage is on the charger under the battery, right where it meets the battery. And it’s a piece of metal probably responsible for a good chunk of the heat transfer to the battery in the first place.

But it shouldn’t get that hot charging 30qs at 1500mah. Was that during the discharge part of the capacity test?

It helps to put some extra bits of rubber or something at all 4 corners to elevate it off the ground a bit more than it already is. And then point a small fan at the charger whenever you’re doing a capacity test. Doesn’t have to be a big fan or at high speed. Just a little PC sized fan on low with the charger raised a bit off the ground is good enough to keep cells under or around 35C.

It could use some better cooling built in.

19

Note that getting a cell hotter during charging is actually not a bad thing really.

It’s keeping the cell hot when not charging or discharging which is bad for cycle life :slight_smile:

20

That data information that SIG provided is correct. I have a list from the data sheets for all my cells.

Listing the standard charging rate and the maximum. If those cells are genuine 1.5 amps charging/discharging should not be an issue. I’ve been charging numerous sets of them at 2 amps for many years without an issues.Never getting hot. This has been in various chargers. Among them the same vapcell S4 plus that the op is using.