Power supply questions for the Lowrance...

[optichamp]

Earlier this year I upgraded to a Lowrance 522 at the bow; I have the transducer on the trolling motor. Same as the previous sonar, it is connected to the starting battery/accessory circuits. Usually on the Delta I use the sonar when fishing, and then want the map and speed displayed when running with the big motor. I noticed after one stretch of a couple of hours fishing, the Lowrance would kick off - finally realizing the old Delco starting battery was getting low on voltage, even though it would still start the big motor.

Mercury calls for a battery with 1000 MCA for a 200 Optimax; the Delco was a much lower rating, and of uncertain vintage, so I bought a Optima 34M marine starting battery model with the spec'd 1000 MCA. The Lowrance now stays running just fine for a couple hours at a stretch. The downside is, when I start the big motor, most of the time the voltage still drops low enough to turn off the Lowrance, making necessary a trip back to the bow to turn it back on. Not a huge deal, but not real convenient, either.

Is it normal to have to turn these units back on after starting the big motor? Should I have it connected to one of the trolling motor batteries instead? Should I have bought a bigger starting/deep cycle battery, like the Optima D31M, or similar quality Group 27 dual purpose?

Thanks!

[kopper_bass]

Opti,
I am not a EE, so i dont have a full answer for you, but its clear what is happening to you. Yes, if your big motor is pulling so many Amps that it lowers the voltage on the grid to below the Lowrance minimums, then your electronics are gonna kick off. This isnt a problem with the Lowrance, but more with either where you have it wired to, or something with your big motor drawing too many Amps to crank over. Most guys run both electronics, and 2 livewells for hours before cranking over the engine and things still work fine. My old boat (1994) used to do what you mentioned. Turned out to be an old part on my big engine that needed replacing (i think it was the starter, not sure). Anyway, replacing that fixed the big draw of Amps to crank the motor and thus fixed the electronics kicking off.

Also, there is usually a power box on your boat that has a voltage regulator on it that keeps power constant for your electronics, thus avoiding this issue. Mine is connected to the electronics box under my console. the main power comes there and is then re-distributed with a regulator. You may just need to find a better power source point to connect to.

I would suggest talking to your preferred local dealer/service dept. to assist.

A few other things to consider.
1) Not sure why you want to keep the "bow" system on when you are obviously running the big motor? I assume the Transducer for it is on the TM, and thus out of the water. Doing this greatly shortens the life of your transducer. you should get into the habit of shutting it off anyway when you pull up the TM.
2) You defiinitely DO NOT want to connect the Lowrance power to your trolling motor batteries. This is a no-no. You will surely end up with interference on your display every time you step on the TM to go.

Hope this can help you some,

Kopper_Bass

[BigBoy]

I had a similar problem with a 332c on the console. I first redid the connections for all the power wires. Then I changed out the fuse in the fuse box on the ranger (not the 3amp quick fuse which comes with the devices).

Now they don't turn off when I crank the big motor.

[MikeD]

you have power to the units coming off of a switched circuit that provides no voltage when the key is moved between the run and start position, move the power lead to a new source or run it (fused) directly to the starting battery

[optichamp]

To update folks, I got home one day, pulled out my voltage meter and found 12.5 volts at the starting battery, without the main motor running. The Lowrance had about 9.9 showing on the display.

I started checking and found the old main accessory power rocker switch would sometimes show a .75V voltage drop across it, which was part of the problem. It also used push-on wire terminals. I replaced that switch with one that was rated for 25 amps instead of just 20, and also had screw-on connectors for reliable connections.

Up at the bow, I found the main lead that came to the front, and found it was reading about 1 volt higher than the original wire that supplied the Lowrance power supply. The original wire went through several other connectors, causing a voltage drop. I moved the Lowrance's power supply to the main wire, still leaving a fuse in-line.

With those two changes the voltage at the battery is obviously, still 12.5 Volts, but now the Lowrance is showing 11.9 volts. I made another trip to the Delta and fished all day with it, and the Lowrance stays working, and does not turn off when I start the big motor.

To answer Kopper's earlier question, I only have the 522 at the bow, no other graph on the boat. The original Lowrance flasher is on the dash, and still works fine for a basic depth readout. There really isn't a space for another graph on the dash, and I don't feel like cutting more holes to mount another one.

With the Lowrance at the bow you can switch it to map from sonar, pull up the trolling motor, and select custom gauges, letting you pick what readings you want, such as speed or heading, and the size of the number display. That will give you a readout big enough to read from the drivers seat while running on plane. I navigated with it that way going from Holland Riverside all the way to White Slough and back, and managed to not get lost

I will add most auto supply stores sell inexpensive voltmeters like the one I have, and they are essential for solving problems like this one.