Truth is I don’t use the batteris for a flashlight , but for some gps trackers .
Anyway , the batteries are Samsung 18650-26f 2,600mhA and I’m using a cheap lithium charger rated 4.2V .
Some batteries do get close to it (more like 4.15v) , and the others don’t pass above 4.0x .
It’s not charging time for sure , as i tried to leave them charged for days and didn’t get higher voltage .
I thought maybe it’s the build-in-batteries protection circuit , but that don’t make sense as i getting various voltages from difrrents batteries with the same circuit .
Please help me to figure out how to Solve this problem , and if I need to buy new charger what type it should be .
Sorry for the low English expression ,
and thanks in advance
I had a pair of Sanyo 2800 cells that wouldn’t terminate on any of my Xtar chargers. The cells also got warm. I removed the protection circuits and they now stay cool and the charge terminates normally.
I’ll get pics after the weekend and post here . Ouchyfoot while you might be right and it is can be the protection circuit , there’s still the fact i’m getting various result (from 4.02v to 4.13v , and i’m talking about more then 150 differents batteries so) so I Believe that’s rebuts it .
When the battery volts stabilize lower than 4.2 from a full charge…that means the batteries are slowly loosing capacity (aka developing internal resistance)…it’s normal wear and tear on Li Ion batts
if they have been abused they may be hitting a wall where anything over a certain voltage generates heat.
those are dangerous and should be drained and recycled.seen that a few times.those are the ones that could hit thermal runaway and go boom!
i would try a better charger on the worst offender and watch temp.afterwards wait a few days and see if the voltage drops much.a cell failing in this manner usually drops a lot after charging.
In refernce to the suggestion the batteries allready weared off a bit , everything is possible but they are brand new & it’s the first charge where I can’t get them above 4.1x .
I’m thinking it’s the charger. I had something similar happen on my first 26650 battery. Came with a cheap charger. It wouldn’t charge past 3.? Volts. Found out my Nitecore i4 will charge 26650s, and it charged fully to 4.2v. Get you a good charger (Nitecore, XTAR etc.).
cant see the protection board.
since some charge and others dont i lean toward battery or board issue.
and being new means nothing.they could have sat at 0v several years in a hot warehouse and be bad now.
Hey all ,
I had the chance to do some tests .
Although my chargers rated as 4.2v , the measurement showed only 4.15v .
Also , I’ve tried to charge with a 5v charger (basic usb charger) and could get the batteries to 4.2v finally .
Now I need to make some conclusions , and despite there’s no doubt the chargers are faulty , i’m still not sure what do I need .
Is it right to assume a good 4.2v charger will solve my problem? or might I need some more output voltage (say 4.35v)?
Do you mean you used a basic usb charger that just provides 5v and connected it directly to the li-ion batteries? That is very dangerous.
Also don’t use a 4.35v li-ion charger. It is dangerous to use a 4.35v charger with batteries meant for 4.2v.
This does not look like a proper cc/cv (constant current / constant voltage) li-ion charger. This seem to be it UE09WCP. Li-ion batteries should have a charger that follows cc/cv. Some “li-ion chargers” can be dangerous and / or reduce the life of the batteries. A lot of chinese chargers claim to be “li-ion chargers” but they are simply fake and dangerous.
As I said it was only for a test , the voltage was never raised above 4.2v (as the batteries are consumers) and when it topped to 4.2v I’ve stopped the charge process , the current also kept low then 125mhA (to each cell) .
Yes you’re right , that’s the charger was provided with the batteries .
I have done some reading about cc/cv charge , I can’t understand what is the stutter charge , is it only “pulse” the current?
It is not the way smartphones charging , right? they’rs just fed by continuous voltage and cuts off the charge when full?
Also , may I ask some recommendations for not expensive chargers (will charge 4 cells in parallel , only need to have Mini-USB-A connector , and can be really slow one-two days charge)?
