Heater threashold

Joined
Oct 10, 2018
Messages
79
Hey guys,

Have browsed around and seen differing thoughts on heaters.

I have only so far had one cell that forced the OPUS to stop discharge due to heat. It got hot alright and noticibly hotter than the rest of the cells I have been processing. I could still hold my fingers on it but must have been close to 50 degrees.

Whats the threashold for heat? Do you cull it if its hotter than normal and trips the opus?

Can anyone link me to some more in depth instruction on this?

Cheers.
 
I personally check all cells as they charge with a temp gun during the first hour or so of charging and anything over30C at that time goes into a special box that says possible heater. When the cells are finished charging as I remove them from my charging board I feel them for temp and if it feels uncomfortable then it joins the other ones in the special box. This is kind of a personal preference and somewhat related to ambient temp, i.e. its been cold here and when I charge 40 cells and when done 38 of those are cool to the touch and 2 of them are warmer than the others those go into the box. Its a small box and certainly not full. Once I get my mR swiper built I will check those for internal resistance and see but I am fortunate to have plenty of cells to play with so the 100 or so that I have that are " Heaters "arenot a game changers.
My rule of thumb is do I want this cell in my pack or not If it gets warm at least in my minds eye it is not a good candidate.
So my answer to your question Heater threshold is personal preference but anything approaching 30C for me is questionable.
Here is some discussion on cell packs getting warm etc.
https://secondlifestorage.com/t-18650-temps-during-charging?highlight=heaters

Wolf
 
Scottietheyoung said:
Hey guys,

Have browsed around and seen differing thoughts on heaters.

I have only so far had one cell that forced the OPUS to stop discharge due to heat. It got hot alright and noticibly hotter than the rest of the cells I have been processing. I could still hold my fingers on it but must have been close to 50 degrees.

Whats the threashold for heat? Do you cull it if its hotter than normal and trips the opus?

Can anyone link me to some more in depth instruction on this?

Cheers.

Was it the rightmost cell in the Opus ? This is prone to get heat from the fans hot air.
 
Cherry67 said:
Was it the rightmost cell in the Opus ? This is prone to get heat from the fans hot air.

Yes! Will hunt around for more info on this.


Wolf said:
I personally check all cells as they charge with a temp gun during the first hour or so of charging and anything over30C at that time goes into a special box that says possible heater. When the cells are finished charging as I remove them from my charging board I feel them for temp and if it feels uncomfortable then it joins the other ones in the special box. This is kind of a personal preference and somewhat related to ambient temp, i.e. its been cold here and when I charge 40 cells and when done 38 of those are cool to the touch and 2 of them are warmer than the others those go into the box. Its a small box and certainly not full. Once I get my mR swiper built I will check those for internal resistance and see but I am fortunate to have plenty of cells to play with so the 100 or so that I have that are " Heaters "arenot a game changers.
My rule of thumb is do I want this cell in my pack or not If it gets warm at least in my minds eye it is not a good candidate.
So my answer to your question Heater threshold is personal preference but anything approaching 30C for me is questionable.
Here is some discussion on cell packs getting warm etc.
https://secondlifestorage.com/t-18650-temps-during-charging?highlight=heaters

Wolf

ALL my cells on the OPUS will get over 30 degrees. What is the charge current you are using?
I charge at the max current the opus can deliver which I understand is 1 amp.
Surely not all the 1000 cells I am testing are bad???
 
Scottietheyoung said:
Cherry67 said:
Was it the rightmost cell in the Opus ? This is prone to get heat from the fans hot air.

Yes! Will hunt around for more info on this.


Wolf said:
I personally check all cells as they charge with a temp gun during the first hour or so of charging and anything over30C at that time goes into a special box that says possible heater. When the cells are finished charging as I remove them from my charging board I feel them for temp and if it feels uncomfortable then it joins the other ones in the special box. This is kind of a personal preference and somewhat related to ambient temp, i.e. its been cold here and when I charge 40 cells and when done 38 of those are cool to the touch and 2 of them are warmer than the others those go into the box. Its a small box and certainly not full. Once I get my mR swiper built I will check those for internal resistance and see but I am fortunate to have plenty of cells to play with so the 100 or so that I have that are " Heaters "arenot a game changers.
My rule of thumb is do I want this cell in my pack or not If it gets warm at least in my minds eye it is not a good candidate.
So my answer to your question Heater threshold is personal preference but anything approaching 30C for me is questionable.
Here is some discussion on cell packs getting warm etc.
https://secondlifestorage.com/t-18650-temps-during-charging?highlight=heaters

Wolf

ALL my cells on the OPUS will get over 30 degrees. What is the charge current you are using?
I charge at the max current the opus can deliver which I understand is 1 amp.
Surely not all the 1000 cells I am testing are bad???


I pre-charge all my cells at 1A on my TP4056s that is where I determine the themp. All my off the shelf LiitoKala, Opus and Zanflair "Testers" do their deed at 500mASometimes I will have a cell or two that get a little warm during discharge. Again it's a personal preference. Just like when my cellphone battery gets hot when I use the GPS when traveling and a lot of demand gets put on the cell so it gets hot. I mean 18650 cells are rated for "Normal extreme operation" of about 50Cbut not for long.
There are several references that indicate a temperature of 60C (140F) is the hottest that any 18650 cell should ever be allowed to get up to (if you want it to last a long time). So it is a matter of preference that's all. For me though (I may end up changing my mind) for now I like low temp cells. Just to be fair though I will run some cells through at 1A on the Opus and let you know what I get.

BTW the reason the Opus right cell gets warmer than the others is that it is on the end of the fan stream. The left cell is the first one that gets the cool air and it travels to the right so the right cell gets the heat from all the other cells and cannot cool off as efficiently.The fan is an exhaust fan not an intake fan.
 
I guess a " heater " is a cell that gets hot on standard charge or discharge , which is usually carried out at around 1 or 0.5A ...

This heating is totally dependent on internal resistance of cell .. but the cell will only heat at these high currents ...

As covered on another thread , the normal power-wall operates at much lower currents per cell below one tenth the test charger/discharger level .

If the current is one tenth , the heating effect is one hundredth !!

So if your powerwall normally takes more than 10 hrs to charge or discharge , heaters are fine to use , they won't get the slightest bit warm , and losses will be below 1% for even the worst cells .
 
You should Install a Fan Mod, fr internal ist Not sufficient.
 
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