I have a new SR King and am using unprotected panasonic high quality cells in it. I have the following issue: After running the light for a while and checking cell voltages, 3 cells consistently come down at the same rate, whereas the 4th cell is always .1v ahead, or behind. For example, when pulling the cells at 4.02v, one cell will be at 4.12v. This seems worrisome, though I know that that cell will never over discharge, not before the others anyways. Is it my king or is it that one cell is performing far better than the other 3?
I do, but they’re all protected and I’m afraid they’ll chew up the contact ring as they’re longer and have very pronounced contacts on the + end. The pannys are very flat and shorter due to the lack of PCB.
I’ll try some other cells though, just to be certain…
Please have a look at the cell in question - is there anything physically different about the ends that would compromise contact with either the head or springs ?
You know, everything checked out w/ the cell. In fact, I used it to run the SRK off one cell. It was pulling 5.25A, which I thought was a bit low. Didn’t test the other cells. I know that liPo cells need a break-in of 10 or more cycles sometimes, don’t know if this applies here…
My protected cells are TF red and black 2400mAh, they run pretty strong, but I thought the Panasonics would be best, they pack the best punch in my C8.
Your TF flames won’t damage the light. And for most multi-cell lights like this one, which uses 4 cells, it won’t really matter which batteries you use. I reckon even using ultrafires (the worst battery known to man) would have the same output as your panasonic or trustfire batteries.
There was much hoopla about using flat tops in this light as the buttons on the + end of some cells can damage the contact ring as it’s rather thin. Is this not really a concern? Just something to keep an eye on?
Thanks for your opinions on this. And it’s true that 4 cells in parallel should be able to put out 7A, no problem. I hope it’s not an issue w/ a panny cell as these are supposed to be my premium batteries, but probably best saved for service in my high draw lights. Shoot, my C8 was pulling 4.25A right off the charger. It’s a KD C8, wondering if it’s direct drive? After the cell settled, it was more like 3.5A at the tail.
I’m sure that nipple tops would in fact be the worst cells to use, since the pressure/friction occurs over less of the surface. Flat tops would likely have connectivity issues, making button tops the best cells to use.
Your C8 is most definitely direct drive on high if you’re seeing 4+ amps.
I had the same problem using unprotected panny, one of them was not discharging. Apparently my king has been running on three cylinders only for a while :P
It's just a simple contact problem, variance of height between the four batteries created enough room to prevent strong contact on one battery. And with them all in parallel, the least resistance wins.
I think a small solder blob on all four will solve this. But I didn't bother to try that, as I just use two batteries at a time now. No more problem, much lighter weight as well.
I used to use TF flames in my king, and it didn’t pose a problem. Now I use panasonic ncr18650a batts, they’re even longer but still don’t scratch the contact ring. Not enough to cause a problem anyway.