Sorry if this is a silly question, but I’m looking for a cheap way to generate 230v AC on a boat, with a load of up to about 3kw.
I’ve been told that fridge trailers have a separate small diesel engine to run the fridge unit, and that if I get one from a scrapyard I’ll be able to use it as a generator. I had assumed that these engines just ran compressors rather than generating electricity to run an electric motor, in which case I’d have to just use the basic engine bit and add a 230v alternator.
Can anybody enlighten me on this please, and if this is a viable idea can anybody recommend a scrapyard? (I’m in the Midlands but can travel!)
By the time you’ve finished mucking aorund with a diesel engine and getting hold of the right alternator to do the job you would be better off buying a sine wave inverter. Much quieter too.
The problem about using diesel engines to drive AC alternators to drive domestic equipment is that if you don’t get the alternator and the engine match right you will end up with either a voltage or a frequency problem and that gets expensive.
Do they still do gas powerd fridges for caravans etc?. I know they use to.
This could solve the lack of electricity problem.
When I worked in the building trade a thick farm labourer was wound up by the spark who was stripping out the old wiring.
The farm labourer was sent to his boss with a saled note from the spark to claim his goverment grant so he could convert tv, fridge etc to gas as we were not replacing the wiring.
The same farm labourer also went to the police station for a new wiring licence after we changed our minds & fitted new wires.
Thanks for all the responses, but I guess the answer to my original question is that the engines on fridge trailers don’t generate 230v AC to run the fridges!
Gas fridges are OK except in the height of summer, but a new installation on a boat has to be room-sealed. I’ve never seen a gas freezer, and I probably wouldn’t be able to find a gas-powered washing machine or dishwasher!
Inverters are good for things like fridges, freezers, computers, etc because they provide power on demand and are virtually silent. The big drawback with them is that to get enough power to run a washing machine they are expensive, and you have to have a battery bank that will provide around 200 amps for maybe 30 minutes or an hour at a time, without discharging below 50% capacity. Assuming the batteries are in good condition and you can get them charged up to about 85% that would need a total capacity of about 600 amp-hours.
And, for a boat without an electric hookup, you have to run the propulsion engine to recharge the batteries before you do the next wash. Even if you add an extra alternator that means running the engine for several hours at a time.
So for heavy loads that don’t need to be run at night, a generator with good soundproofing is probably the best option.
AC generation for marine purposes has come a long way over the last
couple of years. The common (and high tech) answer is to have a 2nd alternator fitted to the engine. This reduces the battery capacity requirement.
There is plenty of internet info availab;e on the subject as it’s having such a life changing effect on boat users and their requirement for domestic AC power.
I didn’t really think about it, on the occaisions that I was running with reefers, however I think the motors run generators and the power supplied runs the reefer units. As, when you are on the inside car deck on a ferry, so can’t run the engine, you get hooked up to an electrical input, I assumed that it was a 240v supply for simplicity.
What type of boat is it? Inland canal boat or open water cruiser?
There are different rules for inland canal boats now. These came in a few years ago. This site has inland waterway connected links to all sorts of info here, you should be able to find the info you need in there somewhere.
Many thanks for all the help on this. We’re going to try a low-tech solution first - a portable hot-fill washing machine that’s only 135 watts so can be run from an inverter, and a separate spin dryer.
I suspect this is going to be too much hassle long term, and I’m going to check out some scrapyards to see what’s available from fridge units, but we’ll probably end up with a 230v alternator on the propulsion engine.
The mopacc unit looks good, especially with air conditioning , so I’ll be following that up too.
, so I’ll be following that up too.