Q1) Should I charge them before I use them?…or drain them down some before charging?
Q2) There is a plastic wrap around each battery, but not on the ends. Should I remove the wrap? I think it is just to protect them for shipment, but really, I’m not sure. Does anyone know about removing this?
Q3) I noticed they are a little (3mm?) taller than my first battery [one of these: EFest JV-00500]. I guess the 18650 specification is not a precise spec for size and shape?
Do not remove the clear wrap. It holds the protection circuit on the bottom.
New batteries should arrive only partially charged. I would charge them. You can use them now / partially charged, no harm, you just won’t get full runtime. No need to fully discharge li-ions before recharging. Charge them at any time.
These batteries are protected. The protection circuit is added to the bottom & adds a couple millimeters. Anatomy of a protected battery
1. If you don’t have a multimeter you may discharge them a little before charging.
2. Clear wrap is something like isolator for ptotection circuit.
3. Cells inside are 65mm tall but protection circuit adds a few mms. Efest cell you linked doesn’t have one, that’s why it’s shorter.
The EFest JV-00500 that you linked are actually a different chemistry. LiMn also known as IMR, its a bit safer then li-ions so they don’t usually have protection circuits added.
Be aware that they do sell li-ions without protection but don’t buy them. The battery manufacturers say a protection circuit is required for li-ion.