Book, Essential Boat Electrics, 3rd Edition by Pat Manley

Electricity is vital on board most boats: to keep their systems running and to provide the crew with the services they expect. Much of it will be professionally fitted and many yachtsmen will have little knowledge about the finer detail of electric circuits. But, given the importance of electrical power, some understanding of it is likely to be useful: either to use when required away from the marina or to repair and upgrade your systems.
This book is written to provide that understanding and to allow you to undertake electrical jobs on board yourself, properly and safely. It removes the mystique of boat electrics and gives you the confidence to tackle the jobs when you need to.
Included are the minimum formulae and theory required, focussing more on the practical - using simple language and clear illustrations. There are tutorials, from using a multimeter and wiring a circuit, to troubleshooting electrical faults, all using easy-to-follow photo sequences. The book also looks at tasks such as choosing solar panels and batteries and connecting navigational instruments.
The book is a great manual for a yachtsman needing to keep the power flowing. It has been thoroughly modernised and updated for this new edition by boating electric wizard Oliver Ballam.