Isolator question for 97 johnson

[mnw001]

I have a 97 carbed johnson 115. <br />I believe the alternator output is only about 15 amps. I have two group 31's for my troller and group 24 starting batt. I'm wondering if I bought a 3 batt isolator such as the one JC whitney sells could I charge my trollers on long runs. Is there a better way to do this same thing or should I just buy a $600 honda Generator. I don't want to fry my stator that much I know..Many thanks as always you guys are great.

 

[Mod2]

Re: Isolator question for 97 johnson

Moving to Electrics/Electronics forum.

 

[Boatist]

Re: Isolator question for 97 johnson

If your planing on making a 6 hour trip between troller motor use then you might gain some battery life. If your trips are 15 to 20 minutes then it not going to help at all.<br /><br />Trying to charge 2 group 31 and a group 24 with 15 amps just means your starting battery will get no charge at all. With an isolator it will charge the weak battery first and since trolling batteries will normaly be at a lower charge than the starting battery almost all the charge will go to the trolling batteries. Charging a single group 31 battery after trolling with a 15 amp charger will take 12 hours or more.<br /><br />Also if your troling batteries are in parallel for 12 volt then you only need a two output isolator. If they are in serries for 24 volts then you can not charge all 3 batteries with an isolator.<br /><br />Last alternator will be at max load all the time and may over heat.