It is safe to use a battery with the protection circuit removed?

[richardcpf]

I had a Blue PROTECTED Trustfire 18650 battery, it was left for 1 week in my table and today when i checked the voltage it was 0. The charger did not detect the battery and it wont charge.

Then i removed the protection circuit in the back, checked again and it read 4.01V. Now it works in the flashlight and it is detected by the charger (white trustifre from dx).

Wanted to know if it is safe to keep using the battery without the protection circuit.

 

[CM]

I'm not going to give you a Yes or No answer since only you can determine that after you do some research and understand the limitations and safety issues with these potential hand grenades and accept the risks if you do decide to use them unprotected. It will also be helpful if you understand the limitations of protection circuits (like the one you have that failed) and what they're designed to protect against.

Having said that, I use unprotected cells in many of my lights and understand the risks involved. If you take care of your Li-Ion cells, they will take care of you.

 

[richardcpf]

I'm not going to give you a Yes or No answer since only you can determine that after you do some research and understand the limitations and safety issues with these potential hand grenades and accept the risks if you do decide to use them unprotected. It will also be helpful if you understand the limitations of protection circuits (like the one you have that failed) and what they're designed to protect against.

Having said that, I use unprotected cells in many of my lights and understand the risks involved. If you take care of your Li-Ion cells, they will take care of you.

I've read a lot about Li-ion safety and I am aware about the danger of these cells when being used unprotected, But just wanted to make sure that a cell without the protection circuit will work a like normal unprotected one.

Thanks for reply!

 

[mdocod]

they are perfectly fine, provided you are pro-active in taking security precautions, charge often, prevent over-discharge, test with a voltmeter before they go on the charger each time to make sure they haven't been over-discharged (<~3V), etc etc.

Charging an over-discharged cell or abused cell is the most likely time for there to be any potential volatile failure. So by checking the cell before it goes on the charger, you know whether it's safe to continue. In single cell applications I feel that the amount of effort involved in being proactive like this is often acceptable. In multi-cell applications, the likelihood of an accidental over-discharge increases, and the amount of work involved with checking all the cells can cause people to become lazy in their efforts.

Eric

 

[VegasF6]

If you don't mind me tacking onto this thread, is there a particular safe way to remove this protection circuit? The one time I tried I managed to short the flat copper conductor to ground and it got unbelievably hot in about a microsecond. Burnt the crap out of my hand.

So, what, this conductor (or flat wire ) runs from the positive down to the PCB under the heatshrink. The battery case is negative. What keeps the darn thing from shorting against the case in normal operation? I had another cell go bad on me and could have at least had an unprotected cell from it, but I got fed up and took it to Lowes and dumped it in the recycle box instead.

 

[richardcpf]

If you don't mind me tacking onto this thread, is there a particular safe way to remove this protection circuit? The one time I tried I managed to short the flat copper conductor to ground and it got unbelievably hot in about a microsecond. Burnt the crap out of my hand.

So, what, this conductor (or flat wire ) runs from the positive down to the PCB under the heatshrink. The battery case is negative. What keeps the darn thing from shorting against the case in normal operation? I had another cell go bad on me and could have at least had an unprotected cell from it, but I got fed up and took it to Lowes and dumped it in the recycle box instead.

There is a yellow tape (high temperature resistant i think) behind the flat wire that goes to the top of the cell. The flat wire has + charge, dont let it make contact it with the body which is -

I carefully removed the protection circuit without having the flat wire contacting the body. After that i wraped the naked battery with tape.