Miko schrieb: Stupid question but never I tried before : if I cut wire from Esc to motor and tomorrow I want longer, is it possible opening carefully plastic around circuit to change completely wires? or soldering directly motor wires?
Hacker 70 OPTO arrived today.....
Yes, this is possible. But as others here pointed out already. You need to have sufficient soldering iron power. I would even say you need at least 80W. Makre sure to move fast. If you need a lot of time to get the solder to melt you will heat up the whole ESC too (which is not good). Thats why you need a lot of power because the ESC is designed to dissipate the heat quickly.
Why not leave some length of cable on the ESC and use that to solder your motor onto?
The video you showed shows a mini quad. These ESC's typically can handle currents up to 20A's. This is not every much and thus not very critical if its not done perfectly.
On the other hand your Hacker 70 is able to deal with 70A constant! Thats much much more.
If you really do this you could take 1 or 2 pictures to show us the solder joint and we can tell you if it looks good or not.