green 18650 laptop battery usage.

[ColdZero]

Hi all on CPF.
I`m looking for some advise if I may ...

First a little info from my end..

I have recently purchased :

2 x Eagletac 18650 3.7 Volt Li-ion 3400 mAh batteries
1 x Eagletac D25LC2 Clicky XM-L (Neutral White)
1 x Nitecore i4 Intellicharger

I have also recycled 5x green 18650 none protected ( possibly Sony ) not sure ? batteries from a laptop.

I discarded any obvous damaged cells after removal and also 1x that displayed next to 0 volts.
I kept the x5 that were at 4.0v...These have remained at 4.0v for approx 3 months.

These are the flat top type cells so would not work in my D25LC2 torch and were also a poor connection in my i4 charger..

So, I have soldered a little `button` on the + terminal of the cells and charged 2x for a few hours and removed them from the charger as soon as it displayed `full`.
I also kept testing the temp of these 2x cells during the charging cycle and noted that the cells felt cool to the touch through out ...
After 12 hours the voltage has remained stable at 4.21v in both cells ( same as my new Eagletac 18650 3.7 Volt Li-ion 3400 mAh after they were charged.

The green cells now fit and work in the D25LC2 but I am unsure of the safety aspect being unprotected...

Is there anything I have done incorrectly of overlooked that I should know about ?
Any info will be most appreciated.

Many thanks

Martin

http://

 

[greeny1]

That looks like a good job with the button, I've done something similar (but nothing like as neatly).

It sounds like the cells you have left are in good enough condition. You havn't done anything wrong at all.


These should be reasonably safe in a single cell light like the DC25, Just don't run them too low. You could do a bit of testing by running them for a while, checking voltage etc, seeing at what point you may lose high on the D25 and using that as a guide to recharging. To be extra safe you are probably best not running them down to much below 3.3-3.4 volts

 

[Colonel Sanders]

At least until you gain confidence in them, you should continue to note the temp when charging. They should NOT get warm. Sounds like you're doing that already though. :thumbsup:

Also, charging on a fireproof surface is never a bad idea.

 

[ColdZero]

Thank you for your replies, I will start to use them and monitor the voltage and continue to check temp whilst charging :twothumbs.

 

[Bumble]

Hi, just to add you may want to monitor the self-discharge rate of the batteries... to see what the actual "condition" of the batteries are like.. as you probably know li-ion are very low self discharge


EDIT!! see they have held 4.0 for 3 months.. thats a good sign

:)

 

[Preamp]

Hi! According to this document from Sony, the US18650GR do not explode even if they are shorted until they're completely drained. Undervoltage or constant overcharging won't let them burst in flames, either. So the worst thing you're likely to encounter are burned skin from bloody hot cells, and, certainly, damaged cells which are no longer useable.
I'm using a couple of those, unprotected, too. I even soldered wires directly to the cells, which is generally said to be a bad idea. Well, it actually is, but I didn't solder to the bottom end of the cell, which would have required a lot more heat than soldering to the "collar", around the Anode.

Regards,
Lasse

 

[ColdZero]

Wow...some good info in that document.
Thank you Lasse

Regards
Martin

 

[VidPro]

that specific light , the turbo kicks out, and it is buck style so the 18650 would not drain below spec very easily at all. It would be a light type that you could "get away" with using an unprotected cell easier.
The reasoning behind avoiding the low voltages is said to be because it forms shunts. All i know for sure is if you discharge to far or for to long, it most certannly damages the cell permanent (even sony cells). It most certannly is a concideration having little shorts inside the battery, and especially when charging fast.