Convoy and thorfire c8 have low voltage protection. And just about any cell will work. If leaving stock Panasonic NCR B will work. But sanyo GA, Samsung 30q, lg hg2. Basically aby namebrand unprotected cell. Stock c8 only pulls 2.8 amps.
Edit just checked those links either of those will work. But for roughly the same exact price I’d choose the sanyo GA
The ga is a better cell its a 10amp cell. The Panasonic is a 6.8 but doesn’t do well above 3-4 amps. Voltage sag is severe. With the ga cells if you ever get into modding or other high powered lights your already ahead of the game cell wise. The Panasonic’s have their place. I use them in powerbanks. And they are fine for under 3 amps. But for the same price the ga is the way to go
Yes, its a copper wire from bottom to the top of the spring
The resistance of copper is more than 10 times better than steel
With protected cells the spring is compressed often so much the windings short to each other, gold plating helps here a lot
But with unprotected cells the spring has its full resistance
I have Convoy C8 clear edition. It’s fit protected battery Panasonic, no problem at all. Since you don’t mention your C8, I’m not sure about the other model.
The default driver limit the current up to 2.8 amp. If you want little bit extra, get FET driver. I change mine to BLF A6 and using Sanyo baterai, the output is much better. But at the moment I changed the driver to DrJones for testing.
It depends on the C8. Some protected cells fit my new edition Convoy C8. A couple of Panasonic 18650Bs from Gearbest fit but are quite tight. We are talking about a few thou extra diameter making a big difference here, so it may vary from batch to batch. Unprotected cells are an easy fit.
As for low voltage warning, once again that depends on the brand of the C8. Convoy and Thorfire definitely have it. Generic ebay cheapies almost certainly won’t. I prefer to use unprotected cells in single cell lights and keep an eye on them with a voltmeter.
I think almost all c8s have spring contacts on the tail cap and the driver board, so flat top or button top (the ones with the knob on top) should work.