Boat Maintenance and Engine Hours Log
Service a marine engine by hours, and keep the impeller and anode record that matters more than almost anything else on a boat.
VE-06 2 pages
Trailers and marine · TM-08
Marine Battery and Electrical Log
A free printable marine battery log — bank register, charge and load readings, anode wear, shore power, solar and the wiring checks that matter.
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2 pages. Choose your paper size — both versions are laid out identically, so neither one gets shrunk to fit.
Print it and write on it
Fill it in type and save
The fillable versions have real form fields — open them in any PDF reader, type into them and save. Printing help.
What this sheet is for
Track battery voltages as a series rather than a single reading, so a bank that is dying is obvious well before it strands you.
Who it is for
Boat owners with a domestic battery bank, shore power or solar, and anyone chasing an intermittent electrical fault afloat.
How to use it
- Record the bank once — chemistry, capacity and the date each battery went in.
- Take resting voltage after the bank has been off charge for a while, or it means nothing.
- Record voltage under load as well as at rest; that is where a tired battery shows.
- Log anode wear at each lift-out, with where each anode was.
What is on the sheet
2 pages, in this order:
Page 1
Printed under the title: A record of the battery bank, its charge readings, the anodes and the electrical system on a boat, where almost every flat battery turns out to be a corroded terminal.
Write-on lines: Vessel · Make & model · Year · Charger / controller · Shore power fitted? · Solar fitted?
Battery bank — fill in once, then update when a battery is changed
Table, 5 rows: No. · Bank · Chemistry · Capacity · Fitted · Replace by · Where
Anodes — shaft, rudder, trim tabs, engine, hull
Table, 5 rows: Date · Location · Wear · Replaced · Notes
Page 2
Shore power, solar and wiring
- Shore lead, plug and socket — no heat damage, no corrosion, no cracked insulation
- RCD or breaker tested with its own test button, not just looked at
- Galvanic isolator or isolating transformer checked where one is fitted
- Battery isolator switches operating, labelled and reachable in a hurry
- Terminals clean, tight and protected — this is where the fault usually is
- Fuses and breakers correctly rated for their cable, and labelled
- Cable runs supported, and nothing chafing where it passes through a bulkhead
- Nothing live sitting in the bilge, and bilge pump wiring above bilge water
- Charge controller settings matched to the battery chemistry actually fitted
- Solar output measured in sun and written in the log below
Charge and condition readings
Table, 11 rows: Date · Bank · Resting V · Under load · Charging V · Charged by · Notes
Questions
Why record a resting voltage and a voltage under load?
A resting voltage tells you roughly how full a battery is. A voltage under load tells you whether it can still deliver current, which is the thing that actually fails. A battery can read fine at rest and collapse the moment the windlass runs.
Does the charger need changing if I fit different batteries?
Charging profiles differ between chemistries, and fitting lithium where flooded lead-acid was is not simply a swap — the charger, the alternator arrangement and the protection may all need attention. Take the settings from the battery manufacturer and record what you set, which is what the log is for.
Related sheets
Outboard Motor Service Log
Service an outboard by hours rather than by dates, and keep the impeller and anode record that decides whether the motor has a long life or a short one.
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Boat Safety Equipment Check
Keep an inventory of the safety gear aboard with the date each item expires, so the out-of-date ones are found at the dock rather than at sea.
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