They say 550W at 2,000 rpm
There you go then try it out but be prepared.
Have a switch on the bars and turn it off under 2000 revs
When my V7III Special was having alternator problems I would turn off my heated gear well before I knew i was going to stop so the battery had a chance to recover
Lets face it overloading a motorcycle electrics is risky business
the 2 10 Watt units should be ok.