Alternator on outboard

[Jack B]

Hi,
I have a mariner 2 stroke 2.5hp (now producing 3.3hp!) and was wondering whether it would be possible to fit an alternator so i could charge my batteries up?, is this possible and how much would it cost?
Thanks jack

 

[William_H]

In practical terms not likely. The OB may be capable of being fitted with a "lighting coil" This is an extra coil or 2 coils mounted under the flywheel where the magnets in the flywheel pass. These lighting coils tend to be designed to light 12v globes so after rectification do not provide a lot of voltage for battery charging. My Johnson would charge at about 1/3 amp at about 13v and I go this up to 1 amp using schotky diodes instead of silicon diodes (4).
If you had in mind an external car type alternator well anything is possible. I doubt you would find room under the cover for an alternator driven by a belt from the flywheel. You might just as easily build your own coils to go under the flywheel.
Most people accept that it can't be done and resort to solar power for battery charging or take the battery home. good luck olewill

 

[Uricanejack]

I can't swear to it but probabaly to small.
If its fitted with ellectrical starter can charge a battery
10 hp no problem its an optional extra.
40 hp comes standard.

 

[VicS]

Generally not available as an option on such small outboards. 4 hp the smallest I have noticed.
As William H says it would require a lighting coil to be fitted under the flywheel and a rectifier added to convert AC to DC.
No lighting coil is listed for the 2 or 3.3 hp models

Even if the 2hp would accept a coil and one was available it would cost several tens of £s plus a few more for the rectifier and for the small output you get would it hardly be worthwhile.

 

[John the kiwi]

http://crew.org.nz/forum/viewtopic.php?f=47&t=21038

well someone did it!
mind you a 3.3 doesnt give a lot of room to play with!

 

[Blueboatman]

I had a Mariner 5, also sold as the 4, 2 str that would accept a 4a lighting coil and rectifier. £100 to have it done some 15 years ago tho..