Topping up leisure batteries from the motor

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Bronco99

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Hi

I'd like to know if I'd be damaging my motor for no real gain if I left it to idle/tiny bit of revs in order to charge the leisure battery through the split charge relay when the solar panels aren't getting any sunlight. There are times when I have to be stationary, need power but have no sun. I don't have shore power access and definitely don't have room for even a small genny.
It's a petrol honda 15.

What's the consensus?

Thanks for reading
 
Personally I would not let it bother me. The engine is easy to service, and the carburetor easy to clean. It’s a Honda so will last thousands of hours. Obviously make sure it doesn’t over heat. Honda put their little engines in generators that can idle forever.
Just be careful not to let a cloud of exhaust fumes engulf you.
 
We are talking a Honda 15hp outboard? Personally I would check the amperage it's putting through on idle. Most engines this size will only pump out a max rated average of 5 or so A/h. Enough to top up a starter battery or run Nav lights but not much more. At idle you may find it is charging but not producing enough current to really make a difference on a large leisure battery. As for prolonged periods of idling, I disagree with the consensus. Gain vs wear is simply not worth it. This isn't like a car where the engine can be divorced from the drive train. Your OB will be spinning gear shafts etc for most of the gearbox and idle will induce the most vibration and gear chatter exacerbating wear and stresses as continuity of motion is disrupted and is amplified through a low rev cycle.
 
The idle screw on the carb or the throttle cable adjustment will get the revs necessary to charge the battery
 
BruceK said:
As for prolonged periods of idling, I disagree with the consensus. Gain vs wear is simply not worth it. This isn't like a car where the engine can be divorced from the drive train. Your OB will be spinning gear shafts etc for most of the gearbox and idle will induce the most vibration and gear chatter exacerbating wear and stresses as continuity of motion is disrupted and is amplified through a low rev cycle.
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All use will cause wear but I think that in a Honda that will last many years and many thousands of hours that the extra wear will not be noticeable but the extra utility the OP will get from his boat will be
 
Is it a 2 or 4 stroke? 4t often has higher output.
The electric start is 12a.
Manual start is 6a
No idea what it is for a 2t but can't see it being a lot.

A generator has a load on it so not sure its comparable to a no load engine running at raised rpm.
I personally would not do that to any of my engines
 
It does seem to boost the voltmeter when the batteries are down and send me back up to a respectable level. is an electric 4 stroke.
 
Plenty of places selling them for that price,why dont you buy a largish solar panel that you can position when you need to charge battery and put it away afterwards,no noisy engine running,no fuel consumed.
 
peteK said:
Plenty of places selling them for that price,why dont you buy a largish solar panel that you can position when you need to charge battery and put it away afterwards,no noisy engine running,no fuel consumed.
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Yes i said I have solar panels 300w albeit flexible. Not so much sun now. Tbh I think my battery is ending its useful life. These prices are nothing like marina. Hope they'renot refurbished starters
 
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