Best way to charge batteries when Boondocking?

My "El Cheapo" golf cart batteries lasted 12 years as well.
Never fully recharged when camping (I run generator every 3 days or never) while in last few years when we stop using big coach, they get charge about once a year.
I think worrying about absorption and float while camping is big overkill.
Even if that will extend battery life by 10 or even 20%, the generator fuel will cost more than new batteries.