Melex 625 shudders under load

[Aidee]

Hi, I have a Melex 625 electric. I have very recently replaced all the batteries. When driving uphill, etc, there is a shudder (worse when under load i.e uphill or when applying full power) , almost like it is not making good contact somewhere. It seems to be electrical of nature, not mechanical.

I have triple checked all electrical connections, and replaced all the battery terminal cables.

Can someone perhaps point me in the right direction.


Thanks!