I bought the Marinco a little over a year ago because they were on sale. Do to life and work they have stayed in there box until a couple of weeks ago. The batteries were of course totally dead. I put them out in the AZ sun for a week and they only charged enough to run for a few minutes. I took one apart and its just a rechargeable C battery powering it so I'm just going to replace the battery as needed. If it wears out I will probably try to put in a brushless motor and a Li Poly battery but that will be a ways down the road.