VEC300-48 Initial Current Setting Problem

[Meakcey]

Hi,
We are working on a golf car project.

We have 48V 5kW BLDC motor and VEC300-48V controller.
We could not exceed 15A initial current even we set on controller program to 40A. Controller could get 120A from battery on the road with sudden accelerations as we observed but when vehicle on the slope, vehicle could not handle that torque due to (I think) low startup current. It seems if controller could try to drain 25-30A from the battery, motor could run on the slope.
Why controller does not exceed 15A starting phase current?

Thanks

[Meakcey]

I think we are the only one come across with this problem.
I've mailed with David also but we could not find appropriate solution.
He lastly suggested to change VEC500 controller.
I don't think the problem would be solved with this changing.