New Video: Sanyo 18650 Cells Tests

quake101

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Jun 19, 2017
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The Sanyo's 18650s are known for being "heaters" and in this video I will share my results of testing 6 different Sanyo 18650 models.


P.S. I didn't see the youtube forum anymore so if I'm not allowed to post this here, I'm sorry.
 
this is alright for posting here. it is relevant to the section ;)
 
I'd say 90+% of the Sanyo 18650s I tested started heating up toward the end of charge. I just don't trust them at all, even if I find a non-heater I would not put it in a pack, I'd be afraid that sooner or later it will start to heat.
 
mike said:
I don't even bother testing the purples anymore. I never considered the individual models of purples, I just put them in a separate bin and they sit there until I can decide what to do with them.


I have a bunch of the purple tops, I'm going to do more testing to see if they keep to this trend.


AntnioPereira said:
I'd say 90+% of the Sanyo 18650s I tested started heating up toward the end of charge. I just don't trust them at all, even if I find a non-heater I would not put it in a pack, I'd be afraid that sooner or later it will start to heat.

Unfortunately I have a lot of Sanyo cells on hand and I'll have to use them. My plan is to make my 2nd 14s120p "bank" Sanyo based and compare that to my first "bank" that's non-Sayno cells.

With that said, I have yet to find a white top Sanyo cell that heats up. I'm in no way saying they can't (just look at their other cells, right?) but, I do trust the white tops the most as of right now.
 
I treat all the Crappy :D sanyo heaters(even the red wrap/ purples) the same: When they start heating up over 50C, I remove them and let them REST for a day. Then re-test them and most of the time they do not re heat, at least not to 50C anyways. I do the same if the will not fully charge.
You can send the purples to me if you do not want them. :D
 
Here's the temperature to beat. This was mine from March 2017.


image_dduhpm.jpg
 
Posted comment on the video and re-posting here:

Nice overview. You did a good job on the video ;)
One thing to note, not all "heaters" are bad. Most of them have developed an oxidation layer between the electrolyte and the lithium. The heating process is the chemical reaction of resorption of the oxygen back into the electrolyte. After 1 or 2 cycles, those cells most likely won't get hot or even warm again. I recommend continuing with the testing and charge those "heaters" a couple more times and see what happens. Between each charge, discharge them to around 3.8V (this is to make sure the chargers start charging in CC mode and not CV mode). We look forward to the results
 
To quote one of my posts about Sanyos from 2013-2016:

My current hypothesis is that the the lithium concentration inside of the LiCo2 anode is higher than usual, and leads to a phenomenon called passivation layering, along with the lower purity of the cobalt compound, caused the problems we encountered in these cells. It's still not certain, but I could come to a conclusion in a few weeks.

Basically, this usually happens in lithium primaries due to their very high molar concentration of lithium, forming a passvation layer as the battery isn't used. This isn't really bad for them, as they aren't rechargeable, meaning it isn't a problem. In fact, it lowers their self discharge rate significantly.

I came to that statement, because I noticed that with my Sanyo cells from that time, their self discharge rate is very low, even for a lithium ion battery. Even my best new cells didn't have that low of a self discharge rate. So, I did some more research, and apparently, that behaviour is quite bad for lithium ion batteries on the first cycles, as by clearing that passivation layer, the internal resistance is quite high in the beginning, resulting in much more heat than usual if a battery was stored for a while. With the lower purity of the cobalt used, it resulted in an actual lower thermal runaway threshold.

That, along with charging a possibly months old pack along using the computer in a high heat environment, lead to the thermal runaways, and the massive recall.
 
I saw this posted on another flashlight battery forum..

They claim it explains the 4 character code after the model number..


image_lvjtlu.jpg
 
Hmm, "#2" shows "R1112" which is more numbers than listed in the #1. So what's the extra digit? Or am I reading what #2 states?
 
I beleive it says "SANYO" or "R1122" are markings required by law in Korea.

On most Sanyos there is also a 4 character code under embossed under the model number.

e.g.) 'N41B = October 9, 2009 production
 
I was putting all the sanyos aside with no real plan for them. After seeing this video, I charged tested and recharged all the green, light blue and white ring sanyos (around 80) and not a single one heated up. Average capacity was around 2,1 - 2,2 a.
 
Christian said:
I was putting all the sanyos aside with no real plan for them. After seeing this video...

Go ahead and grab the other ones and give them a shot too. They may not be suitable for powerwall applications, but they'd work great in flashlights(torches), radios, toys or etc. where 1 or 2 cells are required.
 
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