Smurflight
Newly Enlightened
- Joined
- Feb 10, 2014
- Messages
- 3
I am jumping headlong into Li-Ion cell flashlights (from NiMH) but have some questions regarding multi-cell lights like the Fenix TK61 /TK75. Despite working in computer software I do have a strong background in electronics. It seems that the Li-Ion batteries simply require the same caution and common sense as all other batteries, when it comes to handling and use, with the key difference that ignoring said rules comes with more significant consequences due to the energy densities involved. I reviewed a lot of safety posts and multi-cell flashlight reviews and am left with some questions.
It appears that most people are content to measure cell voltages after charge/rest and after use and use those criteria alone to "match" cells. That seemed OK enough until I read one TK75 review that noted irregularities in runtime expansion when trying out the extension kit. That led to an investigation of battery mAh capacities and subsequently uncovering a cell with something like 200mAh less capacity. I do not recall all of the details but I think that the voltage only method of matching would have missed that issue completely.
From this I draw a conclusion that matching multiple cells for a single flashlight should involve both voltage and mAh capacity matching to be properly safe.
Would this be an overkill position to take or just prudent safety with the materials?
Is voltage matching alone sufficient?
Is ignoring that current capacity mismatch asking for trouble? To this I am thinking yes as the cells age and the difference increases.
Opinions from more experienced forum members are most welcome.
It appears that most people are content to measure cell voltages after charge/rest and after use and use those criteria alone to "match" cells. That seemed OK enough until I read one TK75 review that noted irregularities in runtime expansion when trying out the extension kit. That led to an investigation of battery mAh capacities and subsequently uncovering a cell with something like 200mAh less capacity. I do not recall all of the details but I think that the voltage only method of matching would have missed that issue completely.
From this I draw a conclusion that matching multiple cells for a single flashlight should involve both voltage and mAh capacity matching to be properly safe.
Would this be an overkill position to take or just prudent safety with the materials?
Is voltage matching alone sufficient?
Is ignoring that current capacity mismatch asking for trouble? To this I am thinking yes as the cells age and the difference increases.
Opinions from more experienced forum members are most welcome.