I had the "Magic Power Box" on my rhino. All it did for the rhino was to run the battery down. The rhino was at my cabin so I only drove it on weekends...and every weekend after I installed it, the battery would be dead. Apparently it always had a small power draw, even with the key off, so unless you started the rhino every day or so it would kill the battery. Numerous other rhino owners report the same problem. I returned the one I bought. Maybe the ranger version is different/improved. Good luck, Mike