Jeff Jones

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Tuesday, January 02, 2018
DIY non-skid
Tuesday, March 13, 2018
Anchoring Basics

Clean battery wiring
Rigging your boat for safety at sea and in real world conditions is what it’s all about. Avoiding problems is what all boat owners really want, but let’s face facts, issues tend to rear their ugly head at the least convenient times. When an engine won’t start or the radar doesn’t come on when the fog settles in, a ball-of-snakes wiring mess is no fun at all. So let’s start at the batteries.

CLEAN BATTERY WIRING — Battery terminals should only have two wires, one going to the engine and the other going to a main breaker and terminal block supplying power to the vessel’s system.

Read the installation manual of most marine 12v appliances and it will say: Connect directly to the 12v power source. That doesn’t necessarily mean connect directly to the battery. You’ve seen it, a battery with so many wires connected to the positive and negative leads that the nut is on the last couple threads. This causes bad connections that in turn lead to heat and corrosion. So instead, it’s best to create a place for your main power connections to terminate without stacking them on the battery itself.

Find a place close to the battery that is dry and accessible, then place a terminal block with the amount of terminals needed for your existing systems and future systems. Make sure to place a fuse or breaker on the positive side, again big enough for existing and future systems. Do the same on the negative side but no fuse or breaker needed. I prefer breakers over fuses in all my electrical installations. The cable from the battery to the breaker (positive) and the negative terminal blocks should be 1/0 or bigger, depending on the size of your needs.

BATTERY CABLES TO a main breaker and negative terminal block. Here you can see the battery cables run to a location close to the battery. They will supply the breaker-protected power to the positive side of your 12v systems and a negative terminal block. This is where you’ll terminate wires “directly to the source or battery.”

From your new terminal blocks will be two battery cables — one that runs to your breaker panel main positive lead (now protected with a main breaker), and a negative terminal strip for basic grounding. This may seem redundant, but it actually cleans things up and makes troubleshooting very simple. Not only that, but the option to add new electronics or things like bait pumps and lights, it is all ready ahead of time.

Now the battery looks clean and professional. The only battery cables connected to your battery should be the engine cable and the one that leads to the terminal blocks we are installing. It’s a fun project that really makes things look sharp. Now if a problem should rear its ugly head in a real world situation, troubleshooting will be much easier with your new clean battery wiring. It all starts at the battery.

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Captain Jeff Jones holds a current 100-Ton Masters License and is the owner of Captain on Board. During the spring and summer, Capt. Jeff runs yachts in local SoCal waters up and down the entire West Coast. Capt. Jeff is also an ABYC Certified Shipwright diesel mechanic, and during the winter he takes on projects like re-powers and complete retrofits. He can be contacted at (562) 704-9545, or via e-mail at capt You can also check out his website at

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