Trailwatts extender - power shutdwon

[Kevlasultanpus]

I have just bought a 252wh extender for my 2019 Jam2, and have only been on 2 rides with it.

On both rides i am finding the bike shutdown seemingly for no reason while using the extender. It has occurred over a dozen times. Sometimes i get 5 mins sometimes only a few seconds before it shuts down.

I have eliminated the following

1. The power button getting turned off. It is always still in the depressed mode
2. Low battery. Its has occured through the 80% to 40% range. (I am yet to fully charge and fully discharge, noting it came 80% charged)
3. I thought the loom may have been getting dislodged from the jam2 top tube but it is turning off even on smooth pavement.
4. The main bike battery is 80% (does the main battery power have any influence?)
5. All other connections are tight and loom does not seem damaged.
6. Bike running OK when reverting to main bike battery

Has anyone else had a similar issue??

I've contacted trailwatts and am yet to get a reply, but on ground knowledge may point me in the right direction

cheers