Trolling motor battery charge

[Okanaganfisher]

Hey guys,

So I have a legend xtr 18 and how the rig is setup is the motor and all the electronics on the boat are run off the same battery, which is fine as I never have gotten close to draining that battery.

They have a pre wired in optional 2nd battery bank to run the electric trolling motor, which is completely separate from the other battery and all the electronics.

My question is I have been looking at the add a battery from blue sea, but I don't see the need for the switch as the circuits are already isolated. In my case would I be fine to just run the acr so I can charge my trolling motor battery or is there an actual need for the switch as well?

Will the acr always charge that trolling battery when the main motor is running?

I'm kind of confused with the things I've read so if you can dumb down your answers for me would be much appreciated!

So to recap the circuits are separated already and I'm just wanting to charge my trolling motor battery when I'm running my motor.

Looking forward to your suggestions!

Thanks,
Okanaganfisher

 

[alldodge]

Howdy

As with all questions, we need to now what you have. The legend xtr18 is a nice boat, but since your taking about charging capabilities, we need to know what motor is on the boat, more then what kind of boat it is.

Your thought is correct, but your issue is the alternator in your outboard charges just enough amps in most cases to just keep the starting battery charged. So installing an ACR will allow the ALT to charge the trolling bat, but you need a bigger ALT

 

[Okanaganfisher]

I have a 90 hp mercury with a 35 amp alt.

 

[alldodge]

At 35 amps I don't see the ALT providing much to recharge the other bat. The motor needs about half just to stay running and the rest to recharge the start bat

 

[fishrdan]

The battery switch is nice to have, in case your main battery goes dead, then you can flip the switch to start the outboard.

With only 35 amps output from the outboard, it would take hours (4-5, more?) to recharge a depleted trolling motor battery, which isn't realistic for most people. The ACR will help put some charge back into the trolling battery, but I doubt you'll be running the outboard long enough to recharge the trolling battery. It's best to have a dedicated 120V charger for the trolling battery, so you can charge it while connected to 120V power. They also have dual (triple, quad) bank 120V chargers, so you can keep the engine and trolling batteries charged up.