Battery pack using 18650

I’m looking to build a 18650 battery pack and I’m looking for some advices on building it. The pack will be a 10s or maybe even a 12s. My question is: how do I have to charge the cells when they are connected in series? I know that a single cell needs 4.2 v, but for cells connected in series how should i charge my battery pack? Do i have to multiply the volts for the number of cells in series, or it’s always 4.2v? Also i’m looking to buy an sk3 149kv: How many cells in parallel do you think i need to run it at his full potential? I will buy an antispark xt60 connector from hobbyking, but should I include other security systems in the battery pack as well? (For example a bms or some fuses). Also, can I use a soldering iron to build the pack or it’s bad for the cells? Thank you and sorry for my bad english.

Thats new. I assume you mean XT90-S!

@whitepony does not use any BMS at all… I would recommend using a BMS because it is safer. A fuse is always a good idea too!

You could use a normal soldering iron but the cells can easily get to hot. For soldering a 18650 battery back you should better use a spot welder. You can build your own easily and cheap.

When you will build a 10S pack you’ll need a 42V charger (10 Cells * 4,2V charged).