Hello,

I have a deep cycle marine battery hooked up to a back-up sump pump, and the battery doesn't last more than 30 minutes on a full charge. I may be misunderstanding the way it works, but it is a 6 hour battery, which suggests that I should be getting more than 30mins of pump life.

Other than an issue with the battery, could there be some issue with the pump motor that would draw more juice than it typically would?

Thanks

How many "AH" or amp-hours is the battery rated at?
What is the voltage of the battery? 12V?
What is the horsepower or rated current and voltage of the motor?
Without at least this much info we would be guessing...