Raymarine C80 classic/Pathfinder radar voltage fluctuations

[Slipstream 34]

I have had the boat for around 7 months and finally have the time to investigate this fault. When the engine is running the plotter and radar operate as expected. However when on battery power after about 10-15 mins the plotter screen starts to flicker and the radar trips off - clearly a low voltage issue. This also happens when the radar is on standby. The volts at the battery whilst this is happening is 12.5v. I have checked the voltage at points along the wiring and the voltage is good at 12.5v. The installation was done professionally so I am assuming the wiring is the correct spec. I have just fitted an ST60 Multi instrument at the chart table. This is able to monitor the voltage on the seatalk network. This shows a dip of 1v when the flickering occurs. I have disconnected the radar from the chart plotter and the fluctuations have ceased.

Does anyone know of a problem with the radar that might give these symptoms or am I barking up the wrong tree ?

Thanks in advance.

 

[White Horse]

Try another battery first. It could be the radar is causing the voltage drop and the battery cannot supply enough amps. If it all works ok on the alternator it does suggest a battery problem. Also check all the wiring and make sure the (-) are also nice and clean. You cannot assume because it was done professionally that he knew what he was doing.

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[wizard]

I assume that you are using the correctly sized cable for that length of run to ensure there is no voltage drop?

 

[robmcg]

Have had exactly the same issue. Cabling for the power supply is not big enough. Changed ours to some nice beefy wires and problem gone!

 

[Slipstream 34]

Thanks robmcg

Have had exactly the same issue. Cabling for the power supply is not big enough. Changed ours to some nice beefy wires and problem gone!

Rewired the plotter with 10mm2 cable...problem cured ! So much for the professionals.