I own a humminbird 595c gps/fishfinder that keeps flashing low voltage about 15 minutes into my trip.  It will eventually shut off when I turn my livewells on.  I took the cranking battery out and had it checked out and they said it was fine, but I just dont know what to do.  It just wont keep a charge for some reason,  I turned down the voltage alarm on the unit, but it still dies out after a short period of time.  Any help would be great.

Thanks

I am not sure if this will help but make sure all your connections are tight.

I was having a problem starting my gas motor. It would turn over but would not kick and everytime I turned the key the finder would turn off. It turned out to be a loose battery terminal bolt.

I now tighten the wing nuts with a plier.

I am not sure if this will help but make sure all your connections are tight.

I was having a problem starting my gas motor. It would turn over but would not kick and everytime I turned the key the finder would turn off. It turned out to be a loose battery terminal bolt.

I now tighten the wing nuts with a plier.

x2 Clean your connectors and battery terminal.

Change the low voltage alarm setting to a lower value.

After you check all the  connections you may need to  check your cold cranking capacity on the battery. Also check for an inline fuse on the power supply to the depthfinder. A loose fuse can cause similar problems. I had a similar problem with the depthfinder shutting down when I changed from garmin to humminbird. A higher capacity battery solved my problem.

You may also want to have that battery rechecked on a different tester.  Some machines say they're good, some say not.  I've got a battery here that I know is shot, but it tests good on a couple of machines.

What's the voltage on your battery?  Are you running it of the cranking battery or the TM battery) 

To eleminate bad connections, run a negative and positive wire directly from the cranking battery to the depth finder negative and positive.  If it works that way, then start checking a cleaning all negative and positive connections from the depth finder to the battery.  The reason for doing both, either one can cause the problem.

My bow mounted depth finder will never show over 11.9 volts, while the boats battery indicator and the console mounted depth finder shows 12.7 and 14 with motor running.  There is a bad connection somewhere in the wires going to the bow but it's still working and I haven't felt like chasing the problem down.  You probably have a similar problem, just gotta check and clean until you find it.

thanks for all the replies everyone.  I will get to work on it a bit this afternoon.

Thanks,

Deadeye32

I have the same problem with my Humminbird. The Lowrance at my helm NEVER reads Low Voltage and my livewell has never given out. Nodes are cleaned regulary, but the darn H-bird flashes low voltage on every trip and will shut off on occassion. I personally think it is the unit that is the problem. I am waiting for one more "thing" to happen and then I will be getting another Lowrance.

When you clean your connections be sure to completely clean the fuse holder and fuse end. Scrap them pretty hard. I went through a similar thing years ago and the cause was the fusr holder ends being a bit contaminated.

The wire size and condition will seriously affect the voltage that is available at the front of the boat.  If the wire size is 22 AWG and if is copper it will oxidize over time.  The result will be high resistance in the wire which causes a significant voltage drop.  I would look at the possibility of replacing the wire and lowering the Humminbird alarm threshold.