Not having an easy means to hook up 110v maintainer I've been using one of the 1.5 watt panels. $12, small enough to set on dash-My hope was just to offset normal parasitic discharge in our truck of about 110ma. Figured anything it put back good. Surprisingly it does (did) seem to help.
Plan was to get another when they go on sale as max output is about 100ma at best, however placing inside thru the windshield cuts in about half. Depends though how bright as to how much sun gets thru. Super bright sun will get about 80ma if not so bright may drop to 40ma. With 2 closer to what truck uses. It does extend the discharge time for us. At 2 weeks batts would be about 12.4 instead of 12.2.
Though OP stated a few different things and future plans, Id agree about checking parasitic drains-sounds excessive.
I just went thru mine again yesterday. Though drain more panel output batteries were dropping excessively again. This thread motivated me. Found drain was at 280ma. Not a lot but double what it should be. Easy enough pulling fuses to see which circuit-not so easy determining what to fix. Spent a good part of the day and accidentally found it. Also discovered why it seemed to be intermittent untill it became a constant problem. But a Ford thing.
Checked batteries this morning 12.6 and only charged by driving for 15 min last night. Amazing what a few milliamps can do. Played with the panel. To see what it could do or larger panel. Placing panel outside in full sun, some of aux drains off so parasitic down to about 60ma can actually see positive flow of about 15ma. So another panel maybe or single larger watt is planned.
Checking your parasitic drains would yield what you need for panel. Curious what 10 watt panel with controller you found. Size?
