Hi Jan,

It didnt make a difference whether it was set to hard cut off or soft cut off as the esc's were doing the same thing, allowing the boat to run for approx 3 seconds the slow down. I tried a number of different settings and still got the same result in the end.
I normally run my boat with the esc's set to hard cut off. I only ever run my boat for approx 2-3 minutes then bring the boat in and recharge the batteries. Ive never run the cells under 3.7v. I only tried a different esc that I had but it wouldnt last long with the set up I have in this cat. The esc that I tried was a castle HV120 but I need to run HV 240.
Ill just wait to hear from Hifei and see what there have to say.

Peter