Would it be possible to move the SMH10 from one helmet to the other as you use them? I have an SMH10 too, and when I pull it off its charger, I just pop it onto whichever helmet I'm using that day (each helmet has its own SMH10 base, mic boom and speakers installed). That way you don't have to keep repairing devices, and you can keep the extra SMH10 as a spare.

Cheers!