The battery is the problem but.
I met throttle cut many many times when I build my Meepo Boards.
The easy solution is ESC seting. You need to limit the current of the ESC, limit it down small until that its affordable for the battery.
The cut you have is definitely because the battery CANT supply as much current to the ESC.
That also happen when you accelarate on flat road. not only up hill. Whenever you need high current for long time. The battery cant supply constantly.
Is it my battery max : 60amp, you think that i should turn a little down ?
And do you also think that i should change my current settings for input voltage and battery cutoff ?
yes. a battery claim to be 60 amp may not be able to output 60 amp constantly. You try limit the ESC highest current to 30 AMPs, if the problem gone. you then adjust it higher and higher.
If that does not fix it I once had this happen to me from the receiver being too close to the motor wires. The large current flow would make it cut out.