Originally Posted by Sterling
this is an interesting thread... for a long time i've wondered why the need for an AC genset on a sailboat. the vast majority of the required power is DC - its so infrequent you'd need more than 2kw of AC if you can run Air Con, watermaker
, etc from DC power / house batteries.
anyhow - this gave me an idea. why not the 9hp Yanmar
engine plus the required accessory belts to power 1) large alternator 2) scuba compressor
4) mechanical refrigeration
? a clutch
or simple transmission
would be used to direct power to the correct accessory.
obviously they wouldn't all be run at the same time, but it would be a great way to make the most of the engine and space available.
I couldn't agree more with your comments about AC vs DC.
I told the yanmar dealer that I wanted a BIG output DC generator
, but he kept trying to sell me an AC Mase generator. They run at 3000rpm, are very noisey, use a lot more fuel than a 1GM10
@ 2000rpm and would only give a fraction of the charging
capacity through my AC battery charger
For refrigeration, if I was to bolt a compressor
on to the generator it would mean that I would have to run the generator at least once a day regardless of whether I was plugged in to AC shore power
or not. On balance, I've decided to go the DC fridge/freezer option (just ordered a new waeco freezer/fridge 12V DC system). I suppose I could have both systems, but it's not too high up the priority list at the moment.
When we re-engined to the Yanmar 4JH we got rid of the engine driven compressor on the old Perkins
. Now we will be able to leave the boat for a length of time with the food
in the freezer/fridge not needing regular gen set time (if on shore power!) However, I guess the disadvantage of this is that the batteries will get a deeper discharge since the fridge is running off 12V. Hence longer gen set run time for a recharge when away from shore power
We're going to fit a watermaker in the next year or so. I'm not convinced that running it off the DC genny is a good idea though. If the genny was to fail we would be without watermaking capabilty. However, if we got a 12V (of 230V off inverter) watermaker, we could run it when the main engine's on when underway too. And if both engines fail (e.g. bad batch of diesel) we can still run it off the battery charger
powered by our petrol Kipor 1kW AC genny.
Because it will be a 12V watermaker, we'll probably not get the same GPH rate as an engine driven compressor system, but I think the redundancy is a good compromise.
Anyway, I've gone off my own topic!
For the Yanmar 1GM10, I would like it to have a stop solenoid rather than the mechanical lever stop. I've had a good look online but haven't found of anyone who's added this to the 1GM10. Anyone have any ideas?
I've also been thinking about the need to control the throttle. I was thinking of just adjusting the idle screw all the way up to ~2000rpm.
The little engine generates just under 5hp at this rpm. But if I was to draw the full 150A DC from the alternator I'm worried that the engine will become overloaded and start to produce black smoke. This lead me on to thinking about automatic throttle control, somehow reading the alternators field control wire and adjusting the throttle accordingly. This seems overly complicated though. Perhaps just a manual throlle lever which I can adjust as required might be in order.
The aircraft vernier throttle adjustment sounds exactly what I should get. I've not heard of this before. Do you know where I can get one?
Of the folk that have a similar setup, do you ever find your engine overloaded? What actually happens?
noelex77 - many thanks for taking the photo
of your system. It looks very well engineered. It has given me food
for thought as to whether I should do the same with a small shaft and two bearings from the back of the engine or just bolt on the alternator to the usual spot.
goboatingnow - I've also looked into the kubuta engines. Is yours the Z482? That is an amazing price
for it fully marinized! Where is your source? I was quoted well over £3000 for a bobtail beta 14 (BZ482 based marinized) engine!! That's the price
you pay for living in rip-off Britain!
I've looked into getting a Z482 and marinizing it myself. I think I would just need a block heat-exchanger, raw water
and fresh water pump.
However, by the time I've spent all that money
it would be more expensive than the 1GM10 which is ready to go with a full warranty. The only benifits I can see of the kubota route
are hot water (since fresh water cooled) and smoother running (since 2 cyl). But that's quite a premium!!