Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

LPF Donation via Stripe | LPF Donation - Other Methods

Links below open in new window

ArcticMyst Security by Avery

something wrong with my batteries/charger

Joined
Mar 5, 2012
Messages
942
Points
28
ok so I have about 3 18650's , 6 16340 and 2 10440 and recently I have found it really hard to charge them.
they are all at about 3v now, and when I got them they used to charge in about half a hour to 4.2v.

just to describe the problem, today i had my 10440 battery in the charger at 3:00pm. It measured 3.4v on my multimeter. Now, about 8 hours later, it has gone to 3.41v (WTH). all my batteries are acting like this. Is it the charger or the batteries?

the charger is the one lazerer sells, and the batteries are either ultrafire or trustfire. I know i shouldnt expect much from these cheap items, but I'm kinda bummer that they have malfunctioned already.

And I have to charge these in my room, I have heard so many reports of the batteries exploding, is this possible? and will they explode as in fire, flames, bangs or just release smoke and hiss?

thanks for any help
 





Joined
Feb 23, 2012
Messages
1,282
Points
0
Okay, I'll give it a shot.

3.0V is pushing it for cheap Chinese batteries and can damage the cell. It might not even be able to recharge--might just vent.

Check out post #6, #7, and #9 over at CPF here.

CPF Min Voltage Thread said:
Post #6:
It is especially true for li-ion to not go below the cut-off voltage. Li-po's have almost no voltage sag and are pretty safe to say idle voltage=state of charge=running voltage (at least at a drain of less than about 2-3C). But with a larger sag in voltage of the li-ion you can get small areas inside the battery to destabilize and on the subsequent recharge you can get a puffing, in li-ion's case venting. I've seen as little as 3 cycles below 3 volts/cell puff a lipo, so it's best to not go below 3 volts. 2.75 is just too close to pushing it over the edge where a recharge can vent.

Post #7:
Hello AilSnail,

There are some "general rules" about depth of discharge with Li-Ion cells. These "general rules" are designed to maximize cycle life.

At the end of the discharge, when the load is removed from the cell, you will get better cycle life if the voltage rebounds to around 3.5 volts or higher.

The cut off voltage to make this happen depends on the load on the cell. Normal loads may use a cut off of around 3.2 volts per cell. High loads may be able to get away with a slightly lower cut off voltage. Light loads need a higher cut off voltage.

Charging efficiency with Li-Ion chemistry is nearly 100%. If you have a charger that tells you how much capacity has been put into the cell, you can adjust your usage so that you are using 80% of the cells total capacity. This will keep you from over discharging your cells and will give you excellent cycle life.
Tom

Post #9:
AilSnail;
The quality Li-Ion cells like Sanyo, Sony and Panasonic are not harmed by 3.0 volt discharge.
Most of the Chinese cells are questionable, even when only discharged to 3.5 volts.
I've used hundreds of the quality cells over many years.
Larry

Long story short, try to keep your cells over 3.5V.

If all your cells are acting like that, I think the charger is the culprit. Get yourself a decent charger from DX (Doesn't need to be too expensive) because I think the charger just died.

Although battery explosion is uncommon, with deep discharge like that, it might certainly vent. If concerned that they will explode, get a fireproof pouch like this here. It's only two bucks, so you might as well try it out.

Cheers and good luck!
 
Joined
Jul 19, 2012
Messages
23
Points
0
Nominal voltage of your battery is 4,2V ?
What is the load voltage of your charger and in-charge intensity ?
I don't think it comes from charger. If you let them down to 3V, I'm almost sure they are dead.
 




Top