I have been buying batteries every two years for the last 30 years and I have finally found the ones I beleive is the best.They are the Optima blue top deep cycle. It is a maint free gel type. It is expencive but worth it to me. About $180.00 but will last for about 5 years. I have had mine for 3 years and no trouble, The key is to put them on charge as son as you return home from a trip and keep them on charge untill you go again. You can't run one down in one days trolling either. Gander Mountain sells them as well as other dealers. Go to optima Batteries website to find a dealer.