Issues with Wolf Eyes 18650 rechargeables

[cchurchi]

I have a Wolf Eyes boxer HID that runs on 3 168A batteries and I have (9) LRB 168A 2200 mAH batteries that I have been cycling through it. I charge the batteries individually up to 4.20 volts and check the voltage again before using them. They are usually somewhere between 4.18 to 4.20 volts by the time I end up putting them in the Boxer for use. None of the 168A's has seen more then 20 cycles and none are older then 6 months.

The first problem I had was that one of the batteries would only charge to around 4.12 volts so I started using that rechageable in my Wolf Eyes Sniper, although, maybe I should just recycle it. Anyway, about a week ago, I tried to use my Boxer and it shut off after about 3 minutes. I checked the voltage of all 3 batteries and 2 were 4.17 volts and 1 had dropped down to 3.29 volts. I placed this battery in my Sniper, and it wouldn't even turn on. I assume the protection circuit had activated for some reason. I placed the battery in the charger for 1 second remeasured the voltage - it was now back up to 4.18 volts. This battery will function fine in the Sniper but will continue to shut off my boxer. So now I have 2 questionable batteries that I can't really trust.

Then last night, I try to use my Boxer again and this time I only get 30 seconds out of it before one of the batteries shuts it off again. Battery failure number 3 - SCRATCH THAT LAST STATEMENT - I just remembered that about 3 months ago I had a battery that would cause my boxer to shut down at 35 minutes that I shipped back for replacement. So I've had 4 batteries total fail.

As an additional experiment, I discharged 2 good batteries and 1 suspect battery to 4.00 volts and tried to run them in my Boxer. Once again, the light shut down after about 30 seconds, only this time the light strobed quickly about 10 times before shutting off.

The only real abuse that these batteries have experienced is that I run them until the internal protection activates once the batteries drop down to 2.5 volts.

If this is damaging the batteries then why aren't the batteries set to shut off around 3.00 volts????

Has anyone else had issues like these?

 

[SilverFox]

Hello Cchurchi,

I think your cells did pretty good...

It seems that the battery protection circuits are designed to keep the battery from having a violent event during the next cycle. They are not designed to give you long cycle life.

Most protection circuits have a upper voltage limit of 4.35 volts, and a lower limit of 2.5 - 2.8 volts. If you take a bare cell and use those limits, you get roughly the same life you have reported.

At the upper limit, the electrolyte is destroyed resulting in lower capacity. At the lower limit, the electrodes are destroyed once again resulting in lower capacity. If you go much above the upper limit, the cell runs the possibility of venting with flame. If you go much below the lower limit, copper shunts form that short out during the next charge cycle, once again putting the cell in danger of venting with flame.

The other variable is time. If your cells spend a lot of time fully discharged, the damage is increased. The same goes for the time spent at the upper limit.

I have run tests charging to 4.3 volts, but as soon as the charge ended, the cell was immediately discharged. I have also run tests over discharging, but as soon as the discharge was completed, some charge was immediately put back into the cell. I was able to get a few more cycles using this procedure, but the cycle life was still greatly reduced.

The protection circuit seems to have done its job. Your cells did not vent with flame... 🙂

The best cycle life seems to come when you only use around 80% of the cells capacity, and don't store the cells fully charged in a hot environment. The particulars of doing this involve quite a bit of planning and some record keeping.

Tom

 

[FASTCAR]

I have lots of 168s and have had zero issues.
I charge my boxer batts all at once with included charger.