Has anyone ever experienced, the power on your trolling motor, going up and down, while it's on the same setting? I noticed it last year, but I thought maybe it was all in my head. I replaced the trolling batteries this year, and now it seems more noticeable. The motor is a brute 67 Motorguide 24 volt. I'll be going along on a particular setting (it's variable speed) and sometimes when I click it on again, it seems like I have to turn it up, or down, to get the same power. Any suggestions? Thanks.