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Agility · 16-08-2008, 12:08

I'm specking out a new Atlantic 57 Cat and we are currently using Volvo D55 Saildrives with very high output alternators (Mastervolt 24/150). I don't want the weight and maintenance of a genset.

I could get a similar amount of power output from a couple of Yanmar bolt-on generators and I think the design would be a simpler and more robust so I'm considering swapping the Volvo's for Yanmar's.

Anybody have any experience with the new Yanmar KMG65E?

All I could find was http://www.cruisersforum.com/forums/...tor-12355.html which argues in favor of the Yanmar conceptually.

Nordic cat · 16-08-2008, 14:13

I am going for them on my new 40 ft cat, using the 39 hp engines. You can go up to 6 kVA with an extra control box, weighing around 15 kgs.

You need to take care that only one engine at a time can supply AC power to the mains ring on the boat.

My decision is to also split my battery banks in 2, with 2 chargers, to get the shortest possible charge times.

A simple interlock relay will fix the problem.

The advantage is that these don't load up the bearings at the front of the engine like a high output DC alternator does.

I will just keep the standard alternators and let them charge the start batteries only, and make a manual DC crosslink between the engines if one of the start batteries dies on me.

cheers

Alan

Agility · 16-08-2008, 15:24

Quote:

Originally Posted by Nordic cat

make a manual DC crosslink between the engines if one of the start batteries dies on me.

This made me smile. Sounds like jumper cables....

Agility · 16-08-2008, 15:30

Quote:

Originally Posted by Nordic cat

I am going for them on my new 40 ft cat, using the 39 hp engines. You can go up to 6 kVA with an extra control box, weighing around 15 kgs.

You need to take care that only one engine at a time can supply AC power to the mains ring on the boat.

Wow, somehow I missed that in the spec. So are you getting the generator unit on both engines or just one?

Tim

Nordic cat · 16-08-2008, 15:31

Well - that would save me a few bucks....

Any pictures of the new boat yet?

Cheers

Alan

Nordic cat · 16-08-2008, 15:39

Quote:

Originally Posted by BlueRhapCity

Wow, somehow I missed that in the spec. So are you getting the generator unit on both engines or just one?

Tim

Yes -don't want to unbalance the boat

so both. This power source is important, so therefore will be a redundant setup.

I will also have around 600 -800 Watts of solar panels running through a smart controller.

Alan

priusron · 16-08-2008, 16:06

What RPM does the motor have to turn? This may cause problems if you are motoring and need power but are not going fast enough to generate power. It may also get noisy if you have to turn 3600 RPMs to generate power

Ron

Marinheiro · 16-08-2008, 16:43

from the Yanmar brochure for one power box, approx

1000rpm - 900 watts
1500rpm - 1800 watts
2200rpm - 3000 watts
I initially thought this sounded like a good idea but when I saw these numbers changed my mind. Better to go for a big alternator/inverter combination IMHO

Agility · 16-08-2008, 17:41

Quote:

Originally Posted by Marinheiro

from the Yanmar brochure for one power box, approx

1000rpm - 900 watts
1500rpm - 1800 watts
2200rpm - 3000 watts
I initially thought this sounded like a good idea but when I saw these numbers changed my mind. Better to go for a big alternator/inverter combination IMHO

Hum, seems lie a roughly similar power curve - see attached.

Marinheiro · 16-08-2008, 17:52

But remember the Mastervolt curves are alternator speed, so you can play around with pulley ratios to maximise alternator output, ensuring you do not exceed the alternator's max speed at max engine speed