I have the same problem battery is fine. I just ignore it. I think it has something to do with the way I spliced in my trailer lights package, cause thats when it started.
97 ZJ Chop Top-Buggy 5.2L V8, 249 T-Case
5" Lift, JKS Front and Rear Adj. Trackbars, RE Twin Tube Shocks, RE T-Case Drop, Cut Fenders, Chop Top, Half Doors.
33"x13"x16" Super Swamper TSLs on Black Steelies
Custom Rack, 4 Roof Lights, Roof Back-up Lights