If your batteries are dying that quick you're not maintaining them in the things you dont use often. Lead acid batteries do not like to be discharged over and over and having one sit in a motorcycle not being used is discharging it. Get a cheap maintainer from harbor freight. I use their better one which is 15.00 and I have my truck and atv on it 24/7 when not in use. The cheap fleet farm battery in my atv is going strong for years now.