If you’re planning on installing the latest marine electronics like a fish finder or GPS, consider if your boat’s battery power supply is up to the task.
New fishfinders and GPS units, especially those paired with powerful 1kW CHIRP transducers, require a consistent and clean 12.7V power supply for optimal performance, due to the increased processing power.
Any disruption in the power supply will affect the reading accuracy of a transducer.
In order to maintain 12V from the battery at the back of the boat to the helm and switch panel at the front of the boat, all wiring and components need to be in good working order and fit for purpose.
Signs your battery voltage is lacking
If the voltage at your electronics consistently reads below 12V, you may notice symptoms such as erratic sonar readings, screen flickering, sudden shutdowns, or even failure to power on at all. These warning signs are more pronounced when running multiple devices or operating high-draw transducers.
In severe cases, you might experience loss of GPS signal or inaccurate depth data—issues that can compromise both navigation and fishing success.
The causes of poor power supply
If your main battery is putting out 12V and your main Buzz bar or house feed and behind your dash is less than that, we need to investigate the cause of the voltage drop.
We find the leading cause of low voltage is issues with wiring and nine times out of ten there’s a corroded cable on the negative (ground) side or power line from the battery or house fuse circuit.
Aged or oxidized fuse holders—not just the fuse itself—can introduce resistance into the circuit, creating measurable voltage drops at the electronics end. Even small amounts of corrosion are enough to disrupt a sensitive device. Likewise bus bars and distribution blocks are often overlooked but can corrode and cause critical power drop.
Finally, undersized wiring can be a big culprit in critical voltage drop. If the diameter is too small the wire won’t carry enough current, especially over long distances. Always ensure wiring is appropriately sized for the load and length of run.
Diagnosing voltage drop
A multimeter is the best way to check for a voltage drop. You simply connect the multimeter at the electronic terminals while the system is running and compare this reading to the voltage at the battery.
If you find a significant difference in voltage, this indicates resistance somewhere along the wiring path.
Tracking down these voltage discrepancies early can prevent frustration and potential damage to sensitive electronics.
It’s a good idea at that point to measure the total amp/current load on the system and upgrade the cable size to ensure regulated voltage and durability.
How to fix power issues
Don’t put up with dodgy electrics on your boat. For your enjoyment and safety on the way make sure you get it sorted.
Talk to us about diagnosing and fixing your electrical issues today. We have the marine electronics expertise and equipment to assess the cause of your voltage drop and the marine grade electrical components and wiring to fix the problem.
