Solution for fish finder draining cranking battery?

[Barnacle Bill]

Why is it a problem to use electronics on the TM battery and why will it affect the life of the electronics?

Every time you step on the TM's go button you create a surge on that circuit. Electronics don't like surges. Sometimes it lets the smoke out and they won't work anymore. You may get away with it for years but it only takes one time to blow some very expensive electronics. Some times you don't have any choice and have to use the TM battery. Also you are more subject to interference.

[knox_frog]

Every time you step on the TM's go button you create a surge on that circuit. Electronics don't like surges. Sometimes it lets the smoke out and they won't work anymore. You may get away with it for years but it only takes one time to blow some very expensive electronics. Some times you don't have any choice and have to use the TM battery. Also you are more subject to interference.

Thanks so much for the heads up. Guess I'm gonna have to get on pulling some more wire. Arrrgh.

[joekiller]

Out of all the responses, not 1 mention of your alarms on fish finder.... If you go to settings page and set your voltage alarm it will tell you when it's time to start the big motor or turn stuff off.
You stated that you like to watch the down image so you should hear it. Also it's an option to put it on 1 of your watch box's on screen. Set it at maybe 10 volts ? Think mine are at 9.5 volts maybe.
Not at all saying your battery may not be in good shape cause 2 shouldn't run em down .

[warhawk]

I use a deep cycle battery for starting and running everything but trolling motor . My trolling batteries only run that motor .

This is how my boat is set up. I go one step further and disconnect the trolling motor when I put it on the trailer, and I have a cut off switch on my starting battery that I disconnect when I trailer the boat. My problem is that I would occasionally forget to turn off both fish finders. The cut off switch takes care of that for me.

[hunter]

Chaunc:

I am having that same problem and will follow that same path by installing a seperate battery dedicated to my thirsty Onix and HB 898 FFs.
Hope you good fishing this Winter my friend.

Had that problem until i cleared out the stuff from one of my upfront storage spaces and put a battery in there just to run my front electronics. Wired the electronic cables with clips and inline fuse and hook it directly to that battery. I charge that battery every other trip out but it can be removed after every trip to charge if need be.