I use the positive post for 3 feeds on my bike (all fused separately) my Hex ezecan, Bike cam and the SAE flying lead for my optimate, heated vest and Airman mini compressor. Used this configuration on 4 BMWs so far without any issues and as you say far easier than taking the battery out. It's worth putting a bit of copper grease etc on the 2 rubber O rings the cover loctes into too to help prevent them becoming displaced when you refit the cover.