Outboard alternator

[Stuart]

I was wondering if its at all possible to modify an outboard alternator to pump out more amps to help charge the battery faster?.

Stu

[Spaniard_King]

With my limited outboard knowledge I would say no to 2 strokes and possibly with a 4stroke by changing to a larger capacity Alternator.

[mercury'srising]

Hi Stuart, What model motor do you have and why do you need to charge faster?

[Stuart]

Its a Yamaha 2003 175 2 stroke. I want more grunt to charge faster rather than taking up to 30 minutes to put back in what it takes to start the engine. Its just an idea I dont realy care all that much as I have 1 x 750 CCA battery for starting and 2 x 6 volt deap cycle batterys with 240 amp hours.

Stu

[mercury'srising]

OK You've got plenty of battery power. I am not familiar with an upgrade for one of these, however, check with your Yamie man anyway. Although, providing that your charging system is working to specs you should be OK. Note that the alternator system on an outboard is not as powerful as a motor vehicle. It is a very simple flywheel driven alternator producing AC current which is converted to DC current by a rectifier directly into the electrical system. In my experience with all types of o/boards I have found that they tend to regulate output by battery condition. I would not rely on the alternator on an outboad to fully"recharge" a battery. What you may expect is if you have a battery at say 80% of it's capacity then it may not get any higher. My rule of thumb is to always have fully charged batteries as I believe that apart from never being caught and embarassed at the ramp it also relieves some pressure from the outboard charging system. I have had outboards for nearly 40 years and have "never" had to replace a stator or rectifier in any of them. For convenience in recent years I have been using a small solar charging panel plugged into the auxiliary power circuit when in the garage (panel in window) Best system I have ever used, cheap and safe. Some guys even leave it onboard just laying on the dash. Would'nt hurt eh. Projecta brand p/no SPA100 about $40

[Noelm]

unless there was a later/bigger model available and it is exactly the same as yours, then it would be way too expensive to even attempt to increase charging capacity.

[Noelm]

OH, and I dont think ti would take 30mins to recharge a good battery after a normal start.

[mercury'srising]

I agree Noelm. seems a bit long. I would check alternator output and especially battery condition before going any further with spending $$$.

[Stuart]

30 minutes was just an guess. I wont worry about it, I have plenty of battery grunt and I will get a good charger to charge things up after each trip.

Stu