Helix 9 voltage

This may or may not be a problem but it bugs me. My Helix 9 consistently show about 2 volts LOWER than I know it is getting from my batteries. Testing with a meter at the power connection I get 12.4 to 14+ depending on whether the charger is plugged in or not. The display typically shows around 10.00 – 10.4 or even below into the upper 9s voltage. So far it has not cut out on me but I can’t understand why it is doing that. The little Garmin I have on the console shows over 12 volts all the time. Is there a logical/technical reason for this

You say at the power connection, but where is your power connection? How far away from the battery is your power connection, and how far from that connection to your graph? What size wire are you running to your power connection and from that connection to your graph . My first thought is your running to small of cable. I would be using at least twelve gauge marine wire if not bigger depending on how far away your battery is .

It’s corrosion or poor contact at the battery connection, corrosion or poor contact at a splice in the wiring, corrosion at the plug going into the unit, or undersized wiring. In my opinion, the Humminbird- supplied wiring is undersized. Cut it short and replace it with properly spliced 12-gauge wire. That will solve all the possible problems except for the plug-to-unit one.

It’s a 19 foot Deep-V boat and the Bird is on the bow and the two batteries, in parallel, are in the stern. The wire is 18 gauge, the same or perhaps bigger, than the one supplied, as you state. I never thought of using bigger because that wire on the plug is so small. The voltage reading I took was AT the connector where it goes into the bird.

If you have a spare power cord hook it up to a different battery just to see, or hook it into a friend’s system if they run humminbird.

Although if it’s not causing any issues I wouldn’t worry about it.

From the manual. The Helix 9 uses a 5 amp fuse. Recommended wire size is AWG 12 for your length of run.
And I have noticed my Helix units usually display about 0.2 volts below what I get with a high end multimeter. It may be that your Helix just reads low. I don’t believe there is a voltage offset in the software.

Thanks, guys – you all gave good advice… Never occurred to me to check the wire gauge since I was getting full voltage right up TO the unit. Nothing like going back to the manual. I’m sure I never paid any attention because this unit repaced a smaller one and I just spliced in the the old, 18 gauge wire… another project!
Thanks!

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