18650's from laptop pull took a very long time to charge

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xevious
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18650's from laptop pull took a very long time to charge

In a mix-up, I was sent the wrong battery pack for my laptop. After much back&forth with the idiot seller, he finally agreed to send me the right one. I did not have to return the wrong battery pack. But of course, totally useless to me. And the value wasn’t enough to try reselling. I forgot about it for maybe a year. While going through some junk boxes, I discovered the battery pack. Then it dawned on me — why not harvest the batteries from it?

The 4 × 18650 cells came out easily, as the casing plastic is thin. I checked them & voltage was quite low. After removing the soldered contacts & smoothing out the ends, I popped them into a charger (Nitecore i4). After 4 hours, the batteries were warm but the progress showed only the 1st power level LED flashing. After another 4 hours, same situation. I took off the batteries & tested them. 3.5 ~ 3.6v. I thought maybe they were just bad. But I decided to let them go for another 4 hours. FINALLY, the 2nd power level LED started flashing. After another 7~8 hours, the cells were fully charged. They all tested about 4.2v. After a day of letting them sit, I checked again to see if there was any loss. 4.20v ~ 4.23v. So, they seem to be OK. They are in red wrappers. Very small raised lettering, unpainted: SANYO R1122, which equates to model UR18650ZT. Looks like they could be 2650mAh. Not too shabby, for free, if they’re properly functional.

Anyway, was the very long charging time indicative of any issues? Or was it simply because the chemistry may have never been exercised?

Edited by: xevious on 11/08/2019 - 17:44
Serlite
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Hmm…whenever I’ve fiddled with laptop pulls, I’ve assumed that an abnormally long charge time could be indicative of high internal resistance.

Based on my reading, the Nitecore i4 charges 4 cells at 0.375A each, right? That’s pretty low, which makes me feel like the cells getting warm so early in charging is a warning sign (because it could mean a lot of the energy is being converted into heat instead of being stored in the cell).

A high internal resistance suggests the cells are aging, and would also prevent them from delivering/accepting much current without heating up. I guess you could discharge/charge them some more to see if this was just a one-off (or find someone with the equipment to measure their actual internal resistance and compare it against the spec), but I’d keep a very close eye on cell temperature.

xevious
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Serlite wrote:
Hmm…whenever I’ve fiddled with laptop pulls, I’ve assumed that an abnormally long charge time could be indicative of high internal resistance.

Based on my reading, the Nitecore i4 charges 4 cells at 0.375A each, right? That’s pretty low, which makes me feel like the cells getting warm so early in charging is a warning sign (because it could mean a lot of the energy is being converted into heat instead of being stored in the cell).

A high internal resistance suggests the cells are aging, and would also prevent them from delivering much current without heating up.


The last time I charged a laptop pull battery that took a very long time to charge, it never got above 3v. So I considered it dead. When I said “warm” about these Sanyo cells, it wasn’t abnormal. If anything, the charger itself had gotten pretty warm… which meant it was working hard. In any case, I’ll know if the cells are any good by real-time performance. They are rated at 4.3V maximum. The 4.2V charge finish could just mean age.
amishbill
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Just how low were the voltages when they came out of the pack?

When I had some that started between 1 and 2 volts, they behaved much like yours did. When I had them charging at 300, they hit a certain voltage (about 4, i think) and just kept being warm without actually taking a charge after that.

Here they are. They were the basis of a post I made about the importance of knowing your tools. This particular charger would discharge then measure on the charge phase if set to a quick test, but charge and measure on the discharge phase if set to a full test. With marginal batteries, this can result in wildly inaccurate numbers.

DIY LT1 battery wrap image. "PDF on Google Drive":https://drive.google.com/open?id=1IHIEOi1NXu868IYNCzIM7D2Ulpxchmww

Fresh Sanyo NCR18650GAs already wrapped "for sale HERE":http://budgetlightforum.com/node/69120 if you like.

Kame Sennin
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Red sanyos are known for not liking to stay for extented time with low voltage. After that they tend to get pretty warm when charging, the higher the charge current the hotter they go.

I don't remember very well the exact process but it is about some kind of chemical reaction happening at the anode when staying discharged and it is usually reversible by charging them a few times with a low current so the cells don't heat up to an alarming temp.

I have several cells that i saved that way and now they are perfectly fine and don't heat up any more even when charged at 1A.

Of course i recommand extreme caution when charging that kind of cells : use a charger with cell temperature display and don't let unattended  (but tbh that last one should the standart procedure for all Liion charging)

Lightbringer
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Analysing charger? Put them through a refresh cycles (3× up’n‘down) and see.

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d_t_a
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Red Sanyo R1122 (the R11 is a date code, which corresponds to March 2013 date).

It’s most likely the UR18650A (2150mAh nominal). These are known to have overheating issues at the end of their battery life cycle.

I’ve experienced exactly the same symptoms that you mentioned, which I detailed here:
http://budgetlightforum.com/comment/1213319#comment-1213319

(doing a discharge test with an analyzing charger, after they were “fully-charged”, got me around 900-1100mAh for some samples of them)

And there are many other references of them on the Internet:
https://secondlifestorage.com/showthread.php?tid=303

xevious
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amishbill wrote:
Just how low were the voltages when they came out of the pack?

When I had some that started between 1 and 2 volts, they behaved much like yours did. When I had them charging at 300, they hit a certain voltage (about 4, i think) and just kept being warm without actually taking a charge after that.

I can’t remember exactly, but it was probably 2.2v. I don’t know if the pack had ever been charged. Since they all got up to 4.2v, I think that’s encouraging on the health.

Kame Sennin wrote:

Red sanyos are known for not liking to stay for extended time with low voltage. After that they tend to get pretty warm when charging, the higher the charge current the hotter they go.
I don’t remember very well the exact process but it is about some kind of chemical reaction happening at the anode when staying discharged and it is usually reversible by charging them a few times with a low current so the cells don’t heat up to an alarming temp.
I have several cells that i saved that way and now they are perfectly fine and don’t heat up any more even when charged at 1A.
Of course i recommend extreme caution when charging that kind of cells : use a charger with cell temperature display and don’t let unattended  (but tbh that last one should the standart procedure for all Liion charging)

Interesting to hear that. With mine, the cells weren’t unusually warm. The charger got a good bit warm, though. My charger is that cheap Nitecore i4 “Intelli-Charger”. But I’m going to invest in a good charger soon, with LED display and testing features. Given how many 18650 cells I have now, it makes good sense.

d_t_a wrote:
Red Sanyo R1122 (the R11 is a date code, which corresponds to March 2013 date).
It’s most likely the UR18650A (2150mAh nominal). These are known to have overheating issues at the end of their battery life cycle.
I’ve experienced exactly the same symptoms that you mentioned, which I detailed here:
http://budgetlightforum.com/comment/1213319#comment-1213319
(doing a discharge test with an analyzing charger, after they were “fully-charged”, got me around 900-1100mAh for some samples of them)
And there are many other references of them on the Internet:
https://secondlifestorage.com/showthread.php?tid=303

I’d looked up several sites for the R1122 and the UR18650A had corresponded to a different model. I saw 2 posts, one for 2650mAh and another for 2800mAh. I seem to have given the wrong impression on the charging I experienced—cells were a little warm, but not unusually so. The charger had gotten quite warm, but I think that was because it had been running for so long. In any case, monkeying around with laptop battery pack pulls means I should get a better charger. At least one with LED displays and tests. I had looked into this earlier in the year, but was waiting out to see some new models coming out. I just don’t drain down 18650’s fast enough for it to be a critical need right now, but that’s going to change. Cool
amishbill
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Yup. If you’re going to be playing with laptop pulls you need a testing charger.

DIY LT1 battery wrap image. "PDF on Google Drive":https://drive.google.com/open?id=1IHIEOi1NXu868IYNCzIM7D2Ulpxchmww

Fresh Sanyo NCR18650GAs already wrapped "for sale HERE":http://budgetlightforum.com/node/69120 if you like.

snakebite
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was this a new or used pack?
if new cells at +- 350 ma from your i4 it will take a long time.
i4 will get warm but the cells should not get hot.
if pack was new then the cells should be fine.
i have torn down lots of new old stock packs for cells for homebrew powerwall use and have never encountered a heater.
some packs were 10 years old and built with imfamous red sanyos.
all were good and no heaters.
if your pack is used who knows.
might be fine but could have spent a long time at high temps and full charge.
this seems to be the cause of sanyo and some panasonic cells becoming heaters.

xevious
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snakebite wrote:
was this a new or used pack?
if new cells at +- 350 ma from your i4 it will take a long time.
i4 will get warm but the cells should not get hot.
if pack was new then the cells should be fine.
i have torn down lots of new old stock packs for cells for homebrew powerwall use and have never encountered a heater.
some packs were 10 years old and built with imfamous red sanyos.
all were good and no heaters.
if your pack is used who knows.
might be fine but could have spent a long time at high temps and full charge.
this seems to be the cause of sanyo and some panasonic cells becoming heaters.
It was supposedly a new pack. Seems to make sense based on that, as the cells didn’t get unusually warm at all. Just took a lot longer than I anticipated. I will drain them down in some “tosser” flashlights and then charge up again — will see if that’s a faster cycle.
Muto
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Run em down and charge again, bet they will be fine.
Your i4 was just taxed with the load but that is a good thing as hammering a stiff charge would not have been a good idea when at low voltage from deep hibernation.

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xevious
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Muto wrote:
Run em down and charge again, bet they will be fine.
Your i4 was just taxed with the load but that is a good thing as hammering a stiff charge would not have been a good idea when at low voltage from deep hibernation.
Thanks! I don’t recall what’s the charging rate of the i4, but I’ll bet it’s low given how cheap it was.
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Any recommendations for a good battery tester? Or just go for any standard one at my local electronics place? I have a few dead laptops lying around at home, now I’m interested in ‘pulling’ as well Big Smile

xevious
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darosk wrote:
Any recommendations for a good battery tester? Or just go for any standard one at my local electronics place? I have a few dead laptops lying around at home, now I’m interested in ‘pulling’ as well Big Smile
Simple battery testers are cheap, but lack the functionality required beyond simple voltage check. More advanced ones end up into professional territory & cost a bundle. Seems the best way to go is with a charger that has testing functions built-in. There are many good choices now — check the charger sub forum.