Depth Finder-Battery question

[beaver44]

I have a Bottom Line 480max depth finder in my boat. I really like the unit, but I have had a continuing problem. When I get in from fishing, I always charge up all my batteries in my boat right away, including my cranking battery, the one the depth finder is hooked to. The next time I go out, I turn on the depth finder when I head out and it works great for about an hour and a half to two hours. Then I start to get some interference, nothing major, just some top clutter and lines from surface to bottom. As more time passes, the interference and lines get worse and worse, usually so bad I just shut the unit off because I'm so upset with it. Does anyone have an idea what might cause this? Is it possible my battery is poor, because it is older? It still starts the boat and runs everything else with no problem. I already exchanged my first depth finder, the same model. This one does the same thing. I really like this Bottom Line and although its not really a "top of the line" unit, I like its power and features, so hopefully I can figure out what the deal is here. Thanks for any help. T.J.

[beaver44]

Any ideas anyone??

[Trailblazin]

Sounds like you settings on your finder ar way off. Try lowering the sensitivity setting.

[fishermn]

I have my Garmin 240 set up with a portable case that I use both in the boat and on the ice. I have noticed similar symptoms when the battery gets really drained, like down to around 9 - 9.5 volts. If your finder has a battery voltage monitor on it, watch that as you are using it to see if the battery voltage is dropping. However, if you are using this as a starting battery as well (and its still starting the motor) that seems like an indication that the battery is OK. Does this happen when you are running the motor? You ay want to check all your connections to make sure none of them are heating up or have gotten corroded.

[beaver44]

I have messed with my sensitivity quite a bit. Like I said, the unit works great for like an hour, and then it starts acting up. The unit also has an SCC feature for eliminating top clutter. Even with this on, it will act up. I don't like running the unit with this on because it really cuts the power down a lot. I just installed the unit in April so there is no corroded connections. All I can think of is the battery is getting old and worn out. It just might not have enough reserve "juice" left to run the unit for a long period of time. Starting a motor just takes short jolts of power, not a long extended draw. Anyone else ever experience this or have any friendly advice? Thanks for responding, hopefully I can figure this out, it's pretty frustrating.

[bwtrout]

i would bet the battery is no longer recovering from the drain by starting your motor. i kept on using a worn out battery that showed 12.4 volts all day using the locator only. the minute i tried using the trolling motor, bilge, or livewell, it would never recover.

[This message has been edited by bwtrout (edited 06-30-2004).]

[Surface Tension]

Are you running the engine or any other electrical equipment when this happens?

[beaver44]

The unit does this with the motor off, and with it on. I don't think my motor has a big enough alternator to make much of a difference, unless I let it run for quite a while. How far do most of you mount your transducers from the motor? I have an Alumacraft Tournament Pro., and I mounted my transducer half way between the motor and the plastic speedo. sensor. I'm not sure if the motor is causing the interference?? Any other ideas? Guess i could just pick up a new battery and see if that solves it. Thanks

[Uncle Grump]

Beaver...

This is a shot in the dark, but try running a fused ground wire between your hull (assuming it's aluminum) and the "-" post on your battery.

UG