To expand on what you said about giving them rest, I think people need to pay attention to that. I used to just run the crap out of one of my rc cars and I was CONSTANTLY charging and discharging the batteries. The minute they would come off the charger, they were back in the car and going another round. When they died, they went right back on the charger. I ended up only getting about 200 charge cycles out of those. After that, I started buying more batteries because I read that they needed a "rest" period after each charge cycle and each discharge cycle. Started doing that and suddenly got close to 400 cycles out of batteries that were the same brand as the others that I was barely getting 200 out of. Since then, I do the same thing with my 18650s. Charge them to full when they are new. Let them sit for a full 24 hours after they are done charging. Use them in my sig 150 and run them down to somewhere between 3.6v and 3.7v. Pop another set of charged batteries in there. Let the ones that just drained sit for a full 24 hours, then throw them on the charger. Once they are done charging, they go back into the charged pile where they sit for at least 24 hours(but no more than 5 days) before they are used again. I have noticed I need at least 3 pairs of batteries at the rate I vape in order to keep this rotation, but I am sure it is better for the batteries.
Here is my rotation:
If I have four sets of batteries(we will call them A, B, C, and D), I will start by charging A and B right away. I will normally use the A set right away this one time, even though it hasn't had the 24 hours for rest. For the day I am using those, the B set is resting and the C set is charging. As soon as the C set is charged, they go in the charged rest pile. After about a day of using the A set, they will be down to the 3.6-3.7v range(we will refer to this point as "drained") and come out of the mod. When they come out, the B set goes in the mod, the A set goes in the drained rest pile and the D set goes in the charger. When the D set is charged, they go in the charged rest pile behind the C set. When the B set is drained, the C set goes into the mod and the A set goes into the charger and the B set goes into the drained rest pile. When the A set is charged again, they go into the charged rest pile behind the D set. When the C set is drained, they go into the drained rest pile, the D set goes in the mod, and the B set goes into the charger. When the B set is charged, they go into the charged rest pile behind the A set. When the D set is drained, it goes into the drained rest pile, the A set goes into the mod, and the C set goes into the charger. This whole sequence just repeats on and on from that point, ensuring each set gets at least 24 hours before going onto the charger after coming out of the mod, and at least another 24 hours before they go from the charger back into the mod. So far, I have seen no noticeable decrease in the capacity of the batteries even after several cycles. It may be a bit overkill, but I don't mind doing the extra work if it makes the batteries last longer.
