2024 40 EFI Charging upgrade?

[FT1980]

I was wondering if there was a relatively simple way to upgrade the charging system on a 40 horsepower mercury outboard. I think they come with stators, not alternators. I believe it's 18 amps. I'd love to get it up a bit.

I have a minn kota 2 bank alternator charger. Problem is it recommends 25 amp input. It worked well for me when I had a 12 volt trolling motor (I only had one set of leads connected to the battery since it's independent). I definitely would get an extra hour of use throughout the day.

I figure if it's impossible or too complex/expensive to upgrade, I'll just leave it be. The system only works when the starting battery is fully charged and stops working when the starting battery falls below a set point (13.6 volts I believe).

If my reasoning is correct, it will charge the trolling batteries, but it will charge less frequently. If leaving it on is a bad idea, I'll just remove the stupid thing

 

[boscoe]

According to Mercury Marine it is an alternator. Just a different type. One that uses separate components instead of all components being mounted in one assembly.

The electrical output of your alternator is a function of the strength of the magnets mounted to the flywheel, the stator coils and the voltage regulator. If even doable it would not be cost effective.

What is the objective? To charge a second 12 volt battery? Or two 12 volt batteries? There are ways to do that.

 

[boscoe]

FYI

 

[FT1980]

According to Mercury Marine it is an alternator. Just a different type. One that uses separate components instead of all components being mounted in one assembly.

The electrical output of your alternator is a function of the strength of the magnets mounted to the flywheel, the stator coils and the voltage regulator. If even doable it would not be cost effective.

What is the objective? To charge a second 12 volt battery? Or two 12 volt batteries? There are ways to do that.

The objective is to charge 2 12v trolling batteries when the outboard is working. To buy a little bit of extra trolling time.

 

[FT1980]

According to Mercury Marine it is an alternator. Just a different type. One that uses separate components instead of all components being mounted in one assembly.

The electrical output of your alternator is a function of the strength of the magnets mounted to the flywheel, the stator coils and the voltage regulator. If even doable it would not be cost effective.

What is the objective? To charge a second 12 volt battery? Or two 12 volt batteries? There are ways to do that.

You are right, it's either not feasible or stupidly expensive to get more charging.

 

[boscoe]

The objective is to charge 2 12v trolling batteries when the outboard is working. To buy a little bit of extra trolling time.

This might be something to consider. What ever amperage is available from the alternator to the batteries will be split over all three batteries.

Trollbridge 12x24

Trollbridge 12x24 The Trollbridge 12x24 allows you to charge your 24-Volt trolling motor batteries from the 12-Volt alternator on your main engine, from your trailer hookup, or from any single or multiple bank 12-Volt charger without risk of running down your starting battery. It works...

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