18650 Overcharge? Need input please...

Hi,

I am a newbie and was hoping for some guidance. I just purchased a Nitecore D4 charger to supplement my D2 charger. I had some Olight 3400 18650s that I used for a few minutes in a Thrunite TN30. After use, I tried to "Top them off" in the new D4 charger. I returned about an hour later and it was still showing as charging, which was strange since they had barely been used. To double check, I placed them in my D2, which immediately displayed a Finished Charge message. I then placed them back in the D4 to double check and the D4 continued to try to charge them.

I was then concerned that the D4 was defective and may have overcharged the Olight batteries. They are protected (and way too big to be called 18650, but thats a different issue). I checked the batteries with a cheap multimeter I have and they are showing 4.15v. Would you say these batteries are still OK to use? I definitely plan on returning the D4, but wasn't sure if I should be concerned with the cells.

Any feedback is appreciated.

Thanks!
Rob

Hi Rob
Reg the cells-The last part of the charge is the longest iirc,basically 4.15v is 95% charged,think positive as will help cell life a little more...........

So yes fine to use imo

I just follow the instructions and do not complicate my hobby unlike others.I charge in the D4 till the light stops flashing and none of this nonsense of topping them up as i never read that in any instruction book.

If you enjoy messing start charging the big boys radio control model batteries where you really can cause severe distress to your batteries and wallet.

Thanks for the responses!

LiIon are very INTOLERANT to overcharge.
LiIons are better kept under 4.2 v, which will prologue their life.
If you are using one of the Nitecore chargers, you're ok.
Here are some web-sites for general & advanced knowledge:
http://lygte-info.dk
http://batteryuniversity.com

If this question has been asked repeatedly, please excuse my ignorance.

How long will a full battery hold a charge if unused? Thanks for any help.


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consitter said:

How long will a full battery hold a charge if unused? Thanks for any help.

Click to expand...

it will take years before it is empty.

There's nothing that forbids you to charge them to 4 v once a year...
60-70% capacity ready to go and no harm to the cell...

@HKJ, you're doing a great job. I am infinitely thankful for your reviews btw...

I just use them.............i top them off from anywhere from 3.6v/3.7v(on my IMR in mods sometimes 3.3v) to 4.2v as its important the last part of the charge i always leave till completion. If i get 450 cycles instead of 500 or 250 instead of 300 with IMR.............i really dont care and who counts anyway. Its years of use even at 200 cycles,by then newer cells,be it hybrids,improved IMR are produced that make cells seem very old anyway by the year. Soon as i get a new light i look for the best cells at the time,with vtc5 rare and lots of fakes,i like the 25r for IMR use. Good happy medium,still use 3400 pany B cells too,still going strong even after charging one to 4.3v by mistake once................no damage at all(well i may have lost a couple of cycles :laughing: )
I have pany B and A cells of years old,still going strong and some have been in daily use too............when they dont hold charge the same due to built up resistance i will recycle and buy more............job done!
Its good to keep an eye on them,its good to use a decent charger(although i wont leave alone over night even though its 99.9% safe). But imho you can get too carried away,some may enjoy it(nothing wrong with that) but for me,i would rather just use the cells and check every so often. Thanks to the vp1 and vp2 its a lot easier than before with the V read out

Above is just me,my opinion and use,its served me issue free for many years,not saying i am right,just works fine for me
I can also see why people can be into cells,checking V every charge,each to their own,again no rights or wrong imo.................as long as the user is happy and safe so what

Hi Ven,

thanks for the detailed account of your experiences, they are similar to my own. Battery improvements are coming fast these days so for me 500 cycles is more than enough. I'd be buying the latest, greatest lithium ion every year or two anyway. Pretty soon you have a dozen cells in each of the usual lithium ion battery sizes and there's no way you'll get to half of that 500 cycle rating.