Simrad Sounder goes NUTS

[jfkal]

Just installed my new Sterling alternator regulator for more Ionnies. Flip side is that as soon as it hits 14.4 Volts my Simrad (Roberstson Stowe) depth sounder goes crazy (speed is okay) starting to let the numbers blink and they go off to 300 ft in the marina and then constantly changing every second accross the whole scale. Cut out the engine and everything returns to normal.
Anyone with similar experience and ideas? I thought of installing a a voltage regulator however then the voltage display would not warn me if voltage goes to high

 

[tyger]

I had a Stowe echosounder on a sailing boat with an outboard auxiliary connected for battery charging. Whenever the outboard ran the echo sounder showed similar symptoms to those you describe.

The solution (proposed by Stowe) was to fit suppressed spark-plugs: it worked.

From this I would guess that the problem was caused by radio frequency interference (RFI).

Could your new charging system be generating RFI? If the regulator is microprocessor controlled then this is a possibility. You might be able to cure the problem with a filter in the sounder's DC supply (perhaps consult a radio technician or electronics engineer).

 

[jfkal]

Will try a filter thanks.

 

[philip_stevens]

Jorge,
If you can throw your mind back to the days of Decca, mine suffered from interference from the alternator, and gave low indicated readings from the master and slave stations.

The remedy then was to fit a suppressor of a certain type/capacitance size under the name of Decca-Mate. It stopped all interference from the alternator and gave full indicated readings on the Decca.

I fitted one, and even though Decca is now defunct, I have left it fitted. There being no reason to remove it, as it causes no problems.

So on this premise, you could fit some car suppressors to your alternator and see if this cures your problem. Fit the type for diesel cars if your engine is a diesel. For some reason there is a difference.

regards,
Philip