Guide 09 stop, check, call
The battery was flat in the morning
Usually a load left on or a charger that is not charging. Sometimes it is the bilge pump telling you something.
Stop first
- A battery that is hot, swollen, leaking or smells of rotten eggs: stop charging it, ventilate, keep flames away, and call a technician.
Checks an owner can do
- Was anything left on: lights, refrigerator, electronics, inverter? Check the battery switch position.
- Did the bilge pump run all night? If so, use the bilge pump guide first.
- On shore power: is the charger on and showing that it is charging? Is the shore power itself on (pedestal breaker)?
- Write the battery reading (from your monitor or charger) in your log each morning for a few days.
Call a certified marine technician when
- The battery will not hold a charge, or the charger shows a fault.
- Corroded, loose or hot battery cables, or any change to battery wiring or chargers.
Sources
- Your boat's, engine's and appliance makers' owner's manuals, The manufacturer
No public source is cited for this guide. Its steps are general precautions; the instructions in your boat's, engine's and appliance makers' manuals come first, and a certified marine technician decides anything beyond these checks.
Reviewed 2026-10-08. Your manufacturer's instructions come first wherever they differ from this page.
Keep a record and brief your technician
Log this problem on your boat with the checks above as a checklist. Tick what you have done, then print a one-page technician brief: the boat, engine hours, what happens, what you already checked and the boat's recent work. When it is fixed, it goes into your maintenance log.
The technician brief is part of Skipper: $1.95 a month or $19.50 a year. Free during preview. Pricing