Using a Honda petrol generator offshore

GHA said:
Rcd
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RCD is useless without an earth of some kind surely? If there is no earth the power would travel through the human and by necessity have to go back up the neutral wire meaning the RCD won't trip because there would be no residual current without a third path. Of course, if you happen to be standing in the water then you're safe as houses :) I'm not an electrician but I know enough that trusting the magic that is RCD isn't a good strategy here.
 
BarryH said:
Most gensets will have an earth stud. Threaded stud that you can connect a decent size cable to. Connect somethibg to this and bung the end over the side., Much the same as lightening protection.....
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That's a better solution than "RCD", I wasn't aware of the earth stud and can only assume others here weren't either, thanks.
 
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lustyd said:
RCD is useless without an earth of some kind surely? If there is no earth the power would travel through the human and by necessity have to go back up the neutral wire meaning the RCD won't trip because there would be no residual current without a third path. Of course, if you happen to be standing in the water then you're safe as houses :) I'm not an electrician but I know enough that trusting the magic that is RCD isn't a good strategy here.
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Well I know it works because I've tripped it before. But never really considered how. If you have a frayed live and you touch it the current won't be going back down the neutral if you get a zap, but how do you get a zap? Still, 30mA ain't much.
 
lustyd said:
That's a better solution than "RCD", I wasn't aware of the earth stud and can only assume others here weren't either, thanks.
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We will be taking the generator with us to the Channel Islands in June. You can test out the theory while I watch from the coach roof, wearing thick wellies. If it shorts out we should have a plentiful supply of electrocuted fish for the BBQ.
 
Laundryman said:
It will run your mains battery charger and that will be much more efficient than the 12v output of the genny.
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Er, why? Are you asserting/assuming that the genset produces 240V or so direct from its alternator which has to be down-converted, with losses, to 12V DC? (From other comments I have no wish to look up the original specifications!)

Mike.
 
No, I'm saying that when it comes to charging the batteries, a mains charger will do the job better than the 12v 8amp output from a suitcase genny. I can't see why anyone would buy a 240v generator, fire it up, ignore the 240v available and use the 12v instead. It would be easier to run the engine and that would provide faster charging too. How or whatever inefficiencies are involved in the generating process is irrelevant. The aim is to charge the batteries. A job that is more easily achieved with a 240v 30 amp charger, than the 12v 8 amp supply from a suitcase genny.
 
Laundryman said:
No, I'm saying that when it comes to charging the batteries, a mains charger will do the job better than the 12v 8amp output from a suitcase genny. I can't see why anyone would buy a 240v generator, fire it up, ignore the 240v available and use the 12v instead. It would be easier to run the engine and that would provide faster charging too. How or whatever inefficiencies are involved in the generating process is irrelevant. The aim is to charge the batteries. A job that is more easily achieved with a 240v 30 amp charger, than the 12v 8 amp supply from a suitcase genny.
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OK, so you really meant "efficacious", not "efficient" (in post #17). I cannot disagree with that, given the numbers you cite.

Also, to charge a battery you need quite a bit more than 12V. Does a nominally 12V output have enough headroom to be useful for charging anyway?

Mike.
 
Also, to charge a battery you need quite a bit more than 12V. Does a nominally 12V output have enough headroom to be useful for charging anyway?

Mike.[/QUOTE]

Don't know. I've never checked the dc output which is described as 12v but may be more. I'm of an age that still thinks of mains as being 240v but I think it is more often 220v these days. I'm no technical wizard, I'm just a generator user. Plugged into the shore power socket gives me the comforts of mains electricity, within reason. Thanks. Alan
 
Generators (in general)
See top left of diagram, two secondary coils, top one produces 240v AC
Lower one is rectified to produce 12v DC.
MainsGen.jpg
 
dancrane said:
Really? The bigger one is said to emit 59db at full load, here... http://www.justgenerators.co.uk/pages/HondaEU20i.htm

...the same site says that at 25% rpm, the smaller one emits the same 52db as the bigger does...won't the EU10i likewise get a little louder at full revs?
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Our EU20i runs very quietly at low speed when running 60amps of chargers but quite noisy when running flat out to power the microwave, I'm surprised it's only 52db. Can't see why anyone would charge batteries from the 12v 8 amp outlet. I don't bother earthing it. There's an RCD immediately after the shore power socket which will trip boat circuits as it senses any imbalance between live and neutral BUT, it won't trip if the imbalance is between the genny and the shore power socket. To protect that bit, an RCD can be plugged into the genny output socket and the lead plugged into that.

I've used it underway a couple of times but it has to be kept fairly level or the oil level sensor will stop it.
 
I don't think that there is any question as to whether or not a petrol generator will charge a battery at sea. The question is whether or not it is practical taking into account the conditions likely to be experienced on the passage to the Azores under race conditions to use a free standing genset in the cockpit
 
Laundryman said:
Had to google "efficacious". Last time I heard that word used was in 'Lilly the Pink' by Scaffold around 1967 ish. You are however correct. It would have been the word to use. Thanks. Alan
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Yes, I remember that despite my aversion to pop. (I call it lithophobia, though I have no idea what the distinction between rock and pop is.)

Now I wish I had been less pretentious and just written "effective" instead of "efficacious". Nearly as good and easier to spell!

Mike.
 
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