Seeking advice for a project or do you want to share the outcome of one? Various technical tips and questions.
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Joined: Sun Jan 25, 2015 2:57 pm
Location: Switzerland


Post by hloerch » Thu Jan 18, 2018 7:58 pm

Hi gang,
I would like to know a bit about your experience with generator.
I think about the new EFOY to to power, up to 240 Amp a day, or a Diesel Generator eg. the Picolo which makes approx. 4 Kw.
Both are around the same price.

What have you on your boat?


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Location: Sardegna / Italy


Post by Milva » Sat Feb 10, 2018 3:37 pm

Grüezi :lol:

I'm thinking about installing a 220 V AC Generator directly on the main engine.
There a two devices on the market:
Dynawatt (Switzerland) ... /index.php

Whisperpower (Netherland) ... power.html

From my point of view they are more or less the same, avaiable in 3.5 and 5 kW versions. Pricing from 3 to 5 grands.

The problem is attaching the gen to the main engine, the volvo penta set is very expensive and made for either a mastervolt or a volvo generator.
Nevertheless i'm not sure if the volvo set is strong enough to transmit 5 kW of mechanical power.

My toughts in this solutions:

- No extra motor, extra tank or petrol
- Producing power AND hot water while running the main engine
- Enough AC power to run a watermaker, the same time
- The engine ist running anyway more or less every day
- No extra maintenance
- Less weight

- More expensive then a Honda 2kW
- Difficulties on attaching the device onto the main engine
- Not portable

Adieu merci

SY Milva

Many thanks to Michael for this forum.

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Location: USA, WA, Seattle

Post by TimOnders » Thu May 10, 2018 4:02 am

The auxiliary engine isn't a particularly good option for power generation if other options are available.

First, the belt-driven accessories won't provide enough load on the engine. Running diesels at light load is both bad for wear and likely to build internal carbon deposits.

Second, your aux engine is very expensive relative to other potential power generators, and life is generally measured in operating hours. Running your aux for power generation uses some of the life of the engine, which is hour-for-hour more expensive than a generator or other power source.

Third, it tends not to be very efficient. Diesel power generation is most efficient when the load, generator and engine are all reasonably well matched and can run at constant speed. Since a generator on the Aux needs to accommodate variying speeds, the regulation system is going to introduce some losses.

If you have space, a diesel generator is probably the most cost-effective solution. You can feed it from a day tank that draws from the main fuel tank, or draw directly from the main.

The EFoy fuel cells are quite nice in that they're easy to install and essentially silent. They're probably more expensive to operate, and you need to consider availability of fuel in your cruising grounds, but they are quite nice (although limited in output capability).

If you don't have any major draws to accommodate (like air conditioning), consider buffering through a battery bank and inverter. You can charge the batteries from the generator/fuel cell at optimal generator output, and consume the power as needed through the inverter.


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Re: Generator

Post by Milva » Sun Jan 13, 2019 7:51 am

Tim, i don't agree:
When you start the motor to move the boat, the system starts to produce the power, the load is enough. The aux itself is taking about 4 kw (arund 10% of the motor power) which is enough to load the crankshaft preventing overwinding.

Second: i found a used one, the whole system (overhauling, pulley etc). was a total of around 1100 euros. S second motor for a generator needs maintaining, additionl weight, lost space etc. I think TCO is fine.

Third: The efficiency of the system is 96 %. Again, in the reality you will use your main engine anyway and while using it, you will consume maybe 50 %of the avaiable power of the motor, THIS is inefficiency...

Running heavy power consumers like a.c. trough an inverter is in my opinion impossible. the battery bank must be huge, the batteries won't last for long.

Anyway i'm very happy with my solution, nobody has to follow, here's a picture:
geni.jpg (58.5 KiB) Viewed 240 times
SY Milva

Many thanks to Michael for this forum.

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