I recently purchased 2 new hummingbird fishfinders for my boat. I can't remember the model numbers. One is a basic grayscale and the other is color and has gps plotting and is navionics capable.

Anyways after hooking them up i have problems getting them to stay on. They turn on and then after a few minutes turn off. Checked the wiring and there is no loose connection.

I think it's the fact that I'm trying to run both fishfinders and my trolling motor on the same battery and it's not enough power.

What's weird is when I power up my gas motor to head to another spot then I can turn the fishfinders on for a few more minutes. The gas motor is hooked up to the same battery if that helps.

I think I just need a second battery, but if anyone has any experiance with a situation like this it would be appreciated.

Thanks

I think it's the fact that I'm trying to run both fishfinders and my trolling motor on the same battery

 

Why?

Cause I think I don't have enough power out of one battery to keep the trolling motor and fishfinders running.

I could be wrong, but I can't think of any other reason that they would power up fine and then shut off.

I'm hoping someone else who knows more about this stuff will be able to help me figure it out

You need a separate battery for the trolling motor. The fish finders will automatically shut off when you have less than 11 volts I think. At least that is what I found out with my old cranking battery and larger Lowrance color unit. Once I jumped the battery and it gained more voltage it was good again.

Cool.

My next question then is should I keep the two batteries seperate? or parallell them? Or does it even matter.

As you can tell I'm pretty ignorant when it comes to this electrical stuff

Put your trolling motor on its own battery and everything else on the other.

Cause I think I don't have enough power out of one battery to keep the trolling motor and fishfinders running.

I could be wrong, but I can't think of any other reason that they would power up fine and then shut off.

I'm hoping someone else who knows more about this stuff will be able to help me figure it out

No, why are you running everything on one battery?

No, why are you running everything on one battery?

Cause I only have one battery right now

Let me preface my response with this . . .

I'm no expert, but . . .

I recommend that you purchase a designated "Cranking Battery" for your motor.  You can connect one of the FF's to the cranking battery, and if the FF is equipped with a battery monitor function, this will keep an eye on your Main / Cranking Battery voltage.

Connect your trolling motor and the other FF to a dedicated TM Battery.  This way, the other TM, if so equipped, can monitor the TM battery voltage.

As for running both FF's at the same time, I can't think of a practical reason fopr doing this.  Assuming that one FF is located at the helm, and the other is located at the bow, by the TM (assuming you have a bow-mounted TM), then there is no need to have both operate at the same time.  Besides, I think that they may even interfere with each other if running simultaneously!

Not knowing just how your boat is set-up, these are my practical suggestions.  If you have some other arrangement on your boat, the basic principles still apply - - - run TWO (2) separate batteries, and don't run both FF's at the same time!

Hope this helps . . .

Tight lines,

Cal

I would NOT put one of the FF on the cranking battery. When you crank your main engine it will draw down the battery temporarily as its starting the motor, that takes a good bit of current. The FF has a minimum voltage required to run and will power off if the power drops below that, even temporarily. This can damage the unit. This is generally why you don't see fishfinders and gps units attached to the cranking battery from dealerships, its not a good idea and can result in damage to the unit.