Heated grips problem 2013 f800gs

If I start the engine with the heated grips switched on they switch off they only work if I switch the heated grips off before starting the engine new battery lithium ion any ideas

The grips are "intelligent" and switch off if it senses the voltage is too low. Starting with the drain on the battery is probably triggering that function.

Solution: switch heated grips off when getting off bike. Switch them back on (if required) after restarting.

(I generally switch my heated grips off a bit before getting to my destination. The residual heat remains and it gives it five minutes to make sure the battery gets a boost before switching off.)

I'm the same, the couple of miles or so into destinations tends to be at slow speeds, so grips are off. I've got a voltmeter fitted & can see the difference it makes....

D