What is typically hook up to your trolling motor batteries and what is on the cranking battery? I have 2 trolling motor batteries and 1 cranking battery. My battery alarm will go off when using the trim after I have been out for about an hour or two. Or if I turn on my live well it will go off after 15 minutes.

trolling motor batteries: trolling motor.
cranking battery: sonar, livewell, bilge, lights, horn, etc.

which battery is setting off the alarm? how old is it? most car parts stores will load test it for free, best way to tell if it's ready to recycle

I replaced the Cranking battery. And still the same problem. Never had a problem with the trolling motor as far as low power. Guess I will need to check the trolling motor batteries. How would you know which battery is setting off the alarm. Usually the alarm goes off when I use turn on the livewells or when I get ready to move to another part of the lake and the motor is up when I use the trim to lower the motor the alarm goes off then after I get to the spot to fish when I raise the motor the alarm does not go off.

If its an alarm on one of your depth finders, you may just have a wiring problem. It can be a bad switch, bad connection, even a faulty fuse holder.

I think its the alarm for the battery because the battery symbol lights up on the dash as the alarm is going off.

has the battery ever failed to start the engine after sounding the alarm?

89.4% of all boat electrical problems are caused by corrosion and/or loose connections...go round the boat & inspect your wiring, connectors need to be took apart & cleaned until they shine. where you have multiple wires on the battery posts, corrosion can get down between 'em and cause weird symptoms. If the battery cables are connected with wing nuts, tighten 'em with pliers.

If that don't fix it, couple possibilities come to mind:
1. get yourself a voltmeter & measure the battery voltage when the alarm sounds. a dragging motor (pump or tilt) *might* cause enough voltage drop to sound the alarm. seems like it ought to blow a fuse if it's that bad, though.

2. two things: a piece of electrical tape and a radio. put the tape on the dash, and turn up the radio louder than the alarm.

Tthanks I'll give that try

Checked all the connections all tight and no corrosions. Your right a piece of tape and a louder radio helps.

Thanks

your battery should be pretty much fully charged at the end of the day, otherwise could be a problem with the motor's charging system. is the tachometer working?

I'd be testing the battery alarm system by checking the battery voltage when the alarm goes off...maybe just a shot sensor or something.

Tach is working fine. I'll check the battery voltage. Didn't think about a bad snsor.

As stated before on terminals need to be clean. Before you go checking a bunch of different things you should take those connecters off and clean them with a wire brush really good and then clean them again. After you do that then you should check the wire going into the connecters and make sure they don't have broken wires and to much gunk in the wires. Now take a volt meter and check the main battery first and see what voltage it reads and then try to make the alarm go off and check the voltage while the alarm is going off and see if the voltage is down. If you don't see a big change there then you need to check the voltage when the motor is running and see if the system on the motor is putting out what it should be,. Good luck