Humminbird 383c fishfinder showing low voltage

tigertank

Cadet
Joined
Mar 21, 2009
Messages
25
My fishfinder is showing low voltage when I have my battery switch to just the trolling motor. 55 pound thrust, 2 batteries 12 volt setup. They also have most of the accessories, starting battery is seperate. When it shows low voltage, which can be set to any number voltage warning you want, I push the gauge on the motor and it shows 3 out of 4 bars. Has anyone had issues with this? Thank you, Al.
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
16,317
The first thing I'd do is check the voltage at the battery. With and w/o the trolling motor running. Then check at the power connector on the fish finder. See if the readings agree with the fish finder. Could be a bad wire or ground on the fish finder. It could also be where/ how the fish finder is monitoring the voltage.
I ran into a similar problem with my Garmin GPS. All voltage checks lead to an issue in the GPS.

I called Garmin tech to ask them where/ how they monitor the voltage. Turns out they monitor the output of the unit's power supply, not the incoming voltage. The offset is basically the power consumption of the power supply. I just offset my alarm by a like amount and don't bother to look at the readings. Problem solved
 

Star

Chief Petty Officer
Joined
Sep 21, 2010
Messages
481
If you are showing 3 out of 4 on a v2 minny your battery is down quite a bit. Was this the motor running? The check is for no current draw. A volt meter is needed to check for battery voltage at each and every connection starting at the battery with the unit powered up. The power plugs on some of the Garmins don't hold up well, is this unit new? My 1 year old cable failed to pass 12 volts after one season on fresh water. The plug on a DV50s only has about .030" interface of the pin and socket due to a design flaw. Also be sure the in line fuse holder contacts are polished and clean.
 

Alumarine

Captain
Joined
Feb 22, 2005
Messages
3,738
I've had 3 humminbirds that all show low voltage without the gas motor running.
The one I use now shows 11.9 volts and my meter shows 12.8 volts at the same connection.
I just set the alarm to 11.5 volts to compensate.
 

tigertank

Cadet
Joined
Mar 21, 2009
Messages
25
No, not a new unit. I'll check with running and off with a voltage meter. I also did drop the voltage alarm on the unit down to stop the beeping, just was concerned, thank you for all the great tips.
 
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