Battery charging kit / guide for Mariner 2-stroke 5hp outboard

[BenMurphy]

Guys,

Honestly, I'm a complete layman when it comes to dealing with outboards. But I have a 5hp Mariner 2-stroke sail drive. From what I understand, I believe it has an alternator that, with some integration, can be hooked up to a 12V battery for charging purposes.

This is for a small sailboat, a Manta 19. I have a small solar panel for my leisure battery already, but I'd like to be able to use the engine to charge as a backup option to ensure that I always have power available for my VHF and depth sounder.

A simple Google search doesn't seem to reveal much. Does anyone know if there's a "kit" that can be purchased for this, or if there are any useful "how to" guides out there?

Thanks,
Ben

 

[TopBanana]

If this is the same outboard, it appears to be covered in Section 2B of this document - http://elrincondepitagoras.es/PAGIN...ry Mariner 4, 5, 6 4 Stroke Sevice Manual.pdf

 

[BenMurphy]

If this is the same outboard, it appears to be covered in Section 2B of this document - http://elrincondepitagoras.es/PAGINAS DEFINITIVAS/documentos/MANUALES/Mercury Mariner 4, 5, 6 4 Stroke Sevice Manual.pdf

Thanks, but that’s the 4-stroke model. I’ve got the 2-stroke, I think it’s set up differently. I have a manual for it, but it’s not really helpful in terms of setting up the charging kit.

 

[penfold]

What does the manual say on the subject? The manual I have for a similar Yamaha talks about needing a rectifier or regulator/rectifier, implying that all the engine is fitted with as standard is the stator coil and lead; a rectifier must be added to avoid cooking the battery.

 

[LONG_KEELER]

Just for information.

I have a 6hp 4T Mariner outboard that came with a charging circuit. I cannot recall what the output was but it was extremely low.

I expect it was possibly only for charging a motorbike type battery for electric starting. If
you do decide to make a purchase, it might be an idea to double check if it will meet your needs. Personally, I would look at increasing solar energy unless you intend doing lots of motoring. The 4T kit costs around £100.

 

[penfold]

Yes, they were once referred to as lighting coils which rather gives the game away; I'd be surprised if they will give more than 4-5 amps and that only at speed.

 

[Gwylan]

Had one, total rubbish. Just enough for a light, hence the name.

 

[peteK]

I fitted a lighting coil under the flywheel because the engine never came with one and used a bridge rectifier to transform it in to dc to charge the battery,I think it may have been a 60w coil,provided enough power to keep the battery topped up on a 19ft Seawych,with conservative use of the electrics.Mariner 5hp two stroke.

 

[William_H]

What does the manual say on the subject? The manual I have for a similar Yamaha talks about needing a rectifier or regulator/rectifier, implying that all the engine is fitted with as standard is the stator coil and lead; a rectifier must be added to avoid cooking the battery.

Sorry to be pedantic but just in case it causes confusion the so called lighting coil on an outboard is typically another coil (in addition to the coil used for ignition) which generates AC as the magnet in the flywheel perimeter passes the coil. The coil then produces firstly a positive wave then a negative wave of current. The rectifier then sorts the 2 polarities out to produce DC as required to charge a battery. The voltage generated depends entirely on engine speed. For an engine operated for a long time at speed and a small battery yes you could cook the battery. You would need a regulator to limit charge current when battery is charged. However mostly for a sail boat with a big battery ie 40 AH or more and short use of engine you would be unlikely to overcharge battery or indeed add any useful charge. (that last is just an opinion based on my experience of lighting coil on an old Johnson 6 that only produced 1/3 amp at cruise revs) ol'will

 

[VicS]

Guys,
Honestly, I'm a complete layman when it comes to dealing with outboards. But I have a 5hp Mariner 2-stroke sail drive. From what I understand, I believe it has an alternator that, with some integration, can be hooked up to a 12V battery for charging purposes.
This is for a small sailboat, a Manta 19. I have a small solar panel for my leisure battery already, but I'd like to be able to use the engine to charge as a backup option to ensure that I always have power available for my VHF and depth sounder.
A simple Google search doesn't seem to reveal much. Does anyone know if there's a "kit" that can be purchased for this, or if there are any useful "how to" guides out there?
Thanks,
Ben

You don't say exactly what model you have ( year and/or serial number) but the battery charging ("alternator") coil and rectifier are shown as accessories on this page
Mariner 5 HP (2-Stroke) Accessories Parts

ITYWF they are fitted as standard on "Sailpower" versions

My experience with a similar sized outboard on a small sailing yacht is that it would not be worth the cost of fitting the battery charging coil and rectifier. My engine,, an Evinrude Yachtwin, had battery charging fitted as standard but unless l used the engine a good deal it did not keep up with battery useage. It did perform a little better than William His Johnson though.

A solar panel, is a much better buy. Mine is only 5 Watts but recharges the battery between weekend sails. A 10 watt panel should be more than adequate for your needs. My plan was to supplement the 5 watt panel with a larger fold away panel if/when needed but I never got round to doing that.

 

[Blueboatman]

I had one one to a 2 stroke Marina 5 long shaft , it was done years ago now £100
Was worth doing , the output around 4A iirc useful when motoring . So you could use an autopilot AND gps AND put some charge into the battery

 

[ghostlymoron]

TBH I wouldn't bother as the output from the engine is very low. I think you'd get more bang for your buck increasing your solar.
I sailed for years in a small 17 footer with only a 10 watt solar panel for charging.

 

[Wing Mark]

£100 fr the lighting coil is similar money to another battery.
The OP will maybe need to think about how he uses his boat and how best to spend his cash.

I can see that being confident that the nav lights and sounder will work anytime the engine is running could be worth £100 to some people.
4A is not a lot, but it can be quite valuable as the sun goes down.
Personally, I d look for a second hand coil etc.