And where do you attach a battery minder?
In my case, I have a pigtail attached to my battery that I tie-wrapped to the engine mount just inside the battery access door on the left side of my cowling. I DID check with my AI before doing so, and had him inspect it after my install. I simply open the access door, remove the caps on the pigtail, and plug my Battery Minder in. It sets on a cart beside my plane in the hangar. Other AIs and A&Ps have seen it and never commented.
I am also aware that other model 172's do not have the large door on the left side of the cowling. I have no advice except to talk to the AI who will do your annual and ask for his opinion.