So I have two mowers. One is battery operated and the other is a large mower. So I mow the front yard every week, but I use the mower in the large back yard and skip a week or two. Sometimes the battery ran out so I added a solar panel and charge controller. This charge controller is NOT waterproof so I installed it under my seat to keep it dry. The panel is only 20 watts, but that's more than enough to keep the battery charged, and the charge controller keeps everything in place. Works great, no problems.