Firstly, if there's been a thread on this before, I apologise. I can't find any good information on the subject anywhere on CPF.
I'm planning an LED bike light build for long distance riding and I want to run it off an eight cell 14.8v (4s2p?) 18650 Lithium Ion battery pack. Maybe even something larger for better run time. The ones I've seen appear to be ready built out of unprotected cells, but with a protection circuit board built in.
(Incidentally, if anyone knows of a good UK supplier of this sort of stuff, please let me know!)
From what I can tell, most Lumicycle brand batteries and various other modern proprietary LED bike light systems use packs made up of 18650 cells in this way. They come with an intelligent charger and you just plug in one cable and off it goes.
Now I've read the do's and don'ts about 18650 Lithium cells and I'm well aware that if you string a load of them together in this way, they can get unbalanced and eventually you'll end up with one or more cells dropping in voltage with the others going up to cmopensate. Best case scenario; your battery's cronked in 20 charge cycles. Worst case, things start to go boom-boom, right?
I know the RC people who use packs like this run balancing chargers and tap into each cell to balance them individually.
So when I look at a pack like this from Battery Junction, being sold with just one lead to charge it an no way of balancing it, do I just plug it into a charger like this and hope it'll work?
Or do I pull the pack apart and solder in wires for a balancing charger?
How the heck do I make the best job of this, whilst prolonging the life of my batteries and not setting fire to myself in the process?
Your help would be hugely appreciated!