15 HP Mercury alternator question

[aeviaanah]

I am waiting on my new Mercury 15hp outboard to come in. The specs show it has a 12amp (138 watt) alternator output. Just curious what is needed to get this thing to charge my batteries. How does this work? Does the motor hook straight up to battery?

My plan was to use a car battery for starting since I have a pull start for emergencies. I thought I may be able to use car battery for bilge pumps as well.

I will go out and buy a deep cycle solely for the trolling motor. After a bit I can upgrade the other battery to deep cycle as well.

Can the alternator charge both batteries at once? Roughly how long will it take to charge a battery off this motor?

 

[fucawi]

Re: 15 HP Mercury alternator question

well if its electric start then it will charge the battery straight out the box ..Car starter battery is fine in my opinion ...you could fit a two way switch or VSR to charge two batteries .your choice. 12A is a good output but the charge current will not be the full 12 A ..thats a rating for powering lights etc ..charge may only be 3 or 4 amps reducing so charge when you get home and before you go out .

 

[aeviaanah]

Re: 15 HP Mercury alternator question

well if its electric start then it will charge the battery straight out the box ..Car starter battery is fine in my opinion ...you could fit a two way switch or VSR to charge two batteries .your choice. 12A is a good output but the charge current will not be the full 12 A ..thats a rating for powering lights etc ..charge may only be 3 or 4 amps reducing so charge when you get home and before you go out .

Are you saying it will charge but not too quickly? Curious if I could get away with one deep cycle battery for the whole boat. Its a 12' boat and i will only have a recirculating pump, bilge pump and 12v trolling motor.