Fully charged, the battery is good for 6 hours of usage on the Fishfinder 3.0 and 5.5 hours on the PRO and PRO+. Just be aware in very cold temperatures the battery may run down a bit faster. It takes roughly 2 hours to charge. In sleep mode, the Fishfinder 3.0 can remain for up to two months without charging. The PRO and PRO+ can remain for up to 6 months in sleep mode without charging.