If you’re out at sea and your boat’s electrics fail, it can be a daunting task to diagnose and fix the problem. However, with the help of expert tips, you can learn how to troubleshoot your marine electrics and solve any onboard problem. Continue reading for some advice on how to avoid being stranded at sea.
After engine breakdowns, electrical failure is the second most common reason for a yacht becoming stranded. Duncan Kent explains how to troubleshoot problems with your marine electrics.
Should you ever suffer total loss of power, the obvious place to start troubleshooting is at the batteries.
Older boats with several previous owners will have had many extras added over the years and, inevitably, some won’t have been installed to a proper standard, which can cause all sorts of problems when trying to track down a fault.
If your battery terminations are corroded or covered with acidic residue (often caused by lack of ventilation), loosen and remove all connected cables, taking care to mark their designation first.
The key to easy troubleshooting is to label every cable indelibly, ideally adding this information to the boat’s wiring diagram.
Then, wipe clean the inside and outside of the battery terminals with a damp cloth, before lightly abrading with fine Emery paper (not wire wool) and smearing them with silicone grease before re-tightening each connection.
As you do so, note that battery clamps are usually tapered, so completely loosen the terminal clamping bolts before putting them back onto the terminals, ensuring they mate together well.
If there are too many connections made directly to the battery terminals, then complications can arise.
A better method is to use positive and negative bus bars, taking a single cable to the bus bar from each battery terminal, with the appropriate large fuse in the positive feed.
This will allow you to use proper crimped and insulated ring terminals, preferably the heat-shrink sealed type.
Marine electrics: Battery failure
If you are suffering from consistent low voltage, disconnect and separate the batteries, leaving each one to settle for a few hours before measuring the voltage across its terminals, then charge each battery separately using a simple single-stage mains charger until it is 100% charged.
Marine electrics: Cabling problems
If your batteries are charged and there’s power at the switch panel, but it’s not reaching your device, then you have no choice but to ‘buzz’ the cable through with a multimeter or a small battery and bulb.
Check that the terminal at the switch is clean and securely connected, before following the cable along the boat.
If there’s power at one end and not at the other then there’s a good chance there’s a fuse, circuit breaker or dodgy junction somewhere along the line.
Meters and battery monitors
The single most useful tool for troubleshooting problems with your marine electrics is a multimeter.
Simple ones are cheap and often adequate for basic tasks, although I’d recommend you spend a little more to get one with a DC clamp ammeter that will enable you to measure current flow through a cable without having to disconnect any wires.