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Red Sanyo 18650 Cells Getting Hot While Charging
#21
I sell all sanyos don't bother testing them anymore
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#22
Sanyo red 18650s from 2013 to 2016 are complete shit. Once they reach over 3.95V, they start dissipating heat, dropping its voltage constantly until it comes down to 3.95V, where the cell in completely fine, but I lose about 30% capacity and high IR(130 mOhms) isn't suited for my applications, even in a 5V powerbank.
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#23
Ok gang, we all know about hot cells, and have read everyone's ideas and thoughts about using them in packs and so on...  but what about the chargers and temperature being raised BECAUSE the charger is hot?   And, how hot should the charger get?

After breaking packs apart, like most, stage 1 for me is to run a first charge to and let sit for a few weeks.   If the voltage after sitting is still > 4.15v, I go to the capacity testing stages.
As all of you know, many of these cells get hot (not just Sanyo batteries) during their first charge out of the laptop battery pack.

I see lots of talk about batteries heating up during charging, but have not found much on this forum about charger heat.
Chargers get old and connectors/springs and even the electronics get anfaulen (for lack of a better term).   They simply go bad after a lots of use.

For my first charging task, I have been using a combination of cheap chargers - most recently, I ditched them all and purchased an opus and an AccuPower from Amazon.
I have found that the opus charger gets REALLY hot and I wonder if the heat from the electronics is simply being transferred to the battery verses the battery heating up due to internal chemistry.

Case in point: I purchased a dozen brand new cells from 3 different sources (for a small test, I used 3 different brands, 4 each per test).  They all had the same specs as the Samsung batteries I get most often.   (Capacity: 2200mAh, Nominal Voltage: 3.70v, Charge Voltage: 4.20v, Charge Current: 1100mA (Std.), Discharge Voltage: 2.75v, Discharge Current: 440mA, Std.).

With this base of brand new cells, this is what I found (in the brand new opus charger):

First charge is at 0.5 amps.

After about 45 minutes , I did a temperature check with my handheld temp meter:
The temperature of the first batch of cells all rose to +/- 2C and were at about 35C/95F.  (not horrible, but surprising as they were brand new)
The temperature of the charger (at the top and on the lcd screen) read at 55C/131F.
I was using the power supply which it came with and it was running at 52C/126.4 at the hottest spot.
The second group of cells were just a couple of degrees less and the third group of cells were about the same.
In all cases, the screen and charger continued to get hotter - at one point, the lcd read 57C/134.6F - and it smelled like it was starting to melt.

The same values were found for ALL 3 sets of batteries with only small variations of above temperatures. 
I did not do the same test on the AccuPower charger, as I didn't have any additional brand new batteries.
Case in point, hot charger, hot brand new cells.
Transfer of heat from charger to cell?

What are you experiences with heat and chargers.
What are your thoughts about working temperatures for chargers?

Thanks, Howie.
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|   Howie Grapek                        South Florida, USA               |
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#24
You can always test if there is a connection by trying a charger where the cell is separated from the charger itself. I never had any cells that got warm, let alone hot, during charging, if charged at max 1A. That means no noticeable heat when touching and hardly any measurable temperature difference in relation to the environmental temperature. In other words, all cells I had until today kept cooler than my bodies temperature (at my hands, which is already much lower than the core temperature) and barely rose above room temperature.

Cells get warm/hot during continuous discharge and I'm using a MC3000 now which has its heatsink right behind the postive terminals of the four cells. But still the cells don't become any warmer than in other discharge situations. At least not beyond an error margin of 2 or 3 degrees celsius. So there might be a difference, but it is negligible. Can't tell with certainty if this is (or isn't) related to heat transfer.
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#25
@howiegrapek
Is the cooling fan working properly and the vents all clear on your Opus?
I have 4 of them and tested over 1000 cells of all different types, included Sanyo heaters, and never experienced the Opus itself overheating as you describe.
True it gets mildly warm when discharging, and when it's working really hard, the fan should be roaring away pretty loudly. On really hot days I have even seen it stop for a rest to prevent itself overheating (mA shows 0 for a short time). When charging there is very little heat at all.
I don't have a temperature meter thing to measure and compare with your reading, but from your description I would say your Opus is faulty or at least, not self cooling properly.
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#26
Hey there watts-on - great question! Actually, no, I know the opus has several temperature sensors internally to protect it, but I don't think I ever heard any fans starting - I didn't even realize that it had an internal cooling fan. Based on that, you may be right - it is probably faulty. I think I'll send it back to amazon and get a new one Thanks for the suggestion.
                                 ''~``
                                ( o o )
+--------------------------.oooO--(_)--Oooo.-----------------------------+
|                                                                        |
|   Howie Grapek                        South Florida, USA               |
|   cell: 303.818.9414                  email: howiegrapek@yahoo.com     |
|   phone: 561-819-9988                 http://www.howieshomestead.com   |
|                            .oooO                                       |
|                            (   )   Oooo.                               |
+-----------------------------\ (----(   )-------------------------------+
                               \_)    ) /
                                     (_/

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#27
The opus fan runs quiet. It doesn't move a whole lot of air. It should be replaced with a better unit.

As far as red hot sanyo's. I have had several get too hot to touch and they are being charged via the TP4056. I don't have a fancy opus or foxnovo or etc. Just a plain TP and a cell holder. With that said, there is "no" external heat being dumped into the cell. It's all generated from the cell itself. And most of the time, it does occur at the 3.95V or 4.10V. That last little bit is so hard to push into it.
However, if you had a way to slow the charging current down to .5A and finish the charge, you may find it'll take the charge. Note also that after these cells were forced to take the charge (there were many that I left in the charger, but I kept an eye and laser-therm on them) until the TP said they were done. Let them sit for a few weeks, do a slight discharge on them, then drop them back in the charger you'll find that a lot of them may rebound and be just fine after that. It's like a rusty bolt. It could be tough to get out, but once it's been removed and cleaned, it'll go back into the hole with minimal effort.
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#28
I wish I hadn't said anything. Past Sanyo cells were all fine apart from two that got very hot during discharge. Today, opening some packs, lots of Sanyo cells (thank you, Acer!). And sure enough, two of the first six I wanted to charge got hot during charging. I will charge them with the MC3000s now, they have a default temperature cutoff at 45°C. Because of how the temperature is measured the cell is actually a bit hotter than the charger thinks it is, resulting in a cutoff at ~50-55°C, which is actually very reasonable.

I'll probably collect all the hot Sanyos and put them through shallow cycles to see if they stop doing that crap.

Oh, btw, my two Opus which I returned because I didn't like them were both incredibly loud. And not only were they loud, the characteristic of the noise was also super annoying. Their bearings are just crap, that's where the noise came from. And because the case is so flimsy the fans don't fit properly which makes everything even worse. I could force the fan to stop spinning by applying some light pressure on the case with one finger.
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#29
(10-02-2017, 08:45 PM)Korishan Wrote: ...
As far as red hot sanyo's. I have had several get too hot to touch and they are being charged via the TP4056. I don't have a fancy opus or foxnovo or etc. Just a plain TP and a cell holder. ... 

Has anyone tried to use the TP4056 pin 1 temp sense input? 
This holds the promise of suspending charging if the measured temperature of an NTC thermistor goes outside limits. Seems like a good thing for these cells particularly...
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#30
I thought about it, but haven't done anything with it yet.
To get it to work ya need to cut the trace to ground and put the NTC in place, and then connect that to ground. Altho, I'm not sure how you regulate it, tho. It uses the voltage difference to determine when to flip the switch and stop charging. So how do you know what size resistor to use with each NTC? Reason I say each NTC, cuz it'd be nice to use the NTC's from the laptop packs we all pull out.
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