fish finder battery= which one?

[Sfritr]

Hey guys

I thought I saw a post about this but my search didn't get anywhere.

Which battery did you hook your fish finder to?  Cranking or deep cycle?  Whats the pros/cons of each?

thanks

[Tim1980]

I have two batteries on my boat I hook one to the trolling motor and one to the fish finder and lights.  If I kill the trolling motor battery just switch them because the fish finder and lights don't take much to run.  So to answer your questiuon deep cycle for me to have a back up battery on the boat.

[Jig Man]

You can hook it to either type of battery but it is best not to hook it up to a battery which is also hooked to a trolling motor.

If one of your's is for cranking then put the sonar on it.

[sneaker]

A fish-finder draws less battery power than the smallest lamp on my boat, if it doesn't include a GPS. So from a power standpoint it doesn't matter where you connect it. However the FF is most likely to shut down when starting your motor if you connect to the cranking battery. On the other hand, I found the t/m to inject a lot of noise on the battery and caused the FF to provide meaningless fish symbols on the screen (turning off the T/M removed the fish).

I carry a small (10 ampere hour ) battery that is just for fish-finders and radios. They do not connect to the engine ground, so are isolated from both engine and T/M noise.  The above problems were eliminated and the FF is providing some usefull data.