Generator Question

[Chris_Robb]

On my new boat (new to me) I have a 4.5KVA HFL genset. I am not sure about the quality of the installation, as it has no dials to show output voltage and amps drawn.

How do I know how near the limit of the gensets power I am taking. What happens if you over do it? Does it just labour and overheat the alternator, or does it trip? The distribution board - which has a master and 3 sub switches cannot do the tripping on overload, can it?

Exhaust system is a straight through rubber exhaust - with good swan neck - but makes a hell of a noise outside, and there is no anti syphon device - which is a bit nasty as it is installed around the waterline, so I always close the cocks when I shut it down.


Any ideas please.

Chris

 

[brianrunyard]

Generator max output = 18.75 amps at 240v.
Hasn't the generator got an overload trip built in? The master switch in the distribution board could be a trip or could possibly be replaced with one.

 

[SolentPhill]

I cant comment on the installation.

4.5 KVA is quite good you can run a few bits with that.

You need to check the cooling system is working ok it should pump out warm water out from somewhere whilst its running.

As far as output goes you can add a few bits yourself take the 2 live wires and put them into a volt meter which you can mount easy. you can make a nice display yourself by taking the live wires out from the output which you can intercept. A panel made out of a panel light in a nice blue that will tell you power is coming out. Then a volt meter will tell you the volts coming out all going through a 16amp RCD. I cant see a generator not having a trip switch 4.5kva you will struggle to overload it unless your running air con and loads of bits at the same time. All these bits can be bought from RS components I just added blue panel lights to mine and it looks great.

 

[ccscott49]

I have a 4.5 kva fisher panda, very similar, I also have no meters on it, but mine does have an overload/overheat/oil pressure/exhaust cut out.
I can tell when I'm pushing mine, it black smokes! But never overloaded it yet, dont think I could even with everything mains I've got, switched on!
Mine is also quite noisy, close up, but not at about 10meters away.
You can get wet/dry exhausts for these wee units, which are really quiet. They split the exhaust into water and gas after it has cooled the exhaust. Halyard make them I think.

 

[Heckler]

i have a standby genny at home, 4.5kva honda petrol, it will run my bungalow but starts to grunt a bit when i put the kettle and stove on together!
stu

 

[Anonymous]

I fitted a moving iron 50A direct reading meter from RS when we first bought the boat - we have a 6.5kVA FP and live aboard mostly with 15A shore power.

The ammeter has prevented us from tripping the shore supply even in the coldest winter weather in the UK and the heat of the summer in Cadiz with aircon running.

I have mounted the ammeter where the cook can see it as well as where I can see it most of the time. As far as I am concerned it is THE solution as it not only informs you of the actual load but trains you to know the current drawn by each piece of apparatus.

Despite having 6.5kVA (28A) available we target a max of 20A but in practice it is seldom up there. I did some sums and discovered that since we buy our diesel as DERV it costs about eight times as much to heat a kettle with the genny as it does with Spanish gas from a large €11.80 cylinder. So we don't do that now /forums/images/graemlins/smile.gif

 

[Chris_Robb]

Hi - your set up sounds ok. I am just worried that if I am not on the boat, someone may try to run too much stuff - the old owner I think said it would stall the genset.

Even in UK I think it would still be cheaper to use the gas!

Have a good summer - hoping to join the circuit in 2009 - roll on!!!

 

[Anonymous]

These small diesels do not like to be overloaded and the alternators are themselves water cooled and can't be run on full load continuously. If I was going to let others have access on my boat I would set the trip to a low level. On ours, I would go for a 15A breaker. Did you say yours is 4.5kVa (can't see the OP in write mode) in which case you might consider fitting a 10A breaker. You can always wire out the breaker when you are in command.

 

[Chris_Robb]

In the same vein, they do not like been run unloaded (bore glasing) so my only feeling is from the engine note on load. - so yes, I will fit strainght away a shunt ameter, followed by a trip, when I have worked out what the normal combination of load is. Battery charger - 70amp - what power is actually taken when batterioes are neary full? Immersion heater 700W - etc

 

[Anonymous]

Re glazing, I think that with the very small diesels we are not in the same territory as bigger ones. There is a not inconsiderable shaft load in running the dc generator, water pump (fresh), raw water pump and ac alternator. You will always have the battery charger running as well and presumably you would never run the generator after the batteries had reached C/50 or C/100 rate unless you needed power for something else like hot water? You are a long way from glazing territory.

Greater damage is caused by flicking the genny on for the odd cuppa as the fuel servo swings hard over until the revs reach the correct level.....starting flat our every time (at least, that's what the FP seems to do). And constant start/stop means that the engine is often running at non-optimal temperature.

I use a moving iron ammeter without a shunt. It is non linear giving you the scale where you want it. Mine is nominal 25A full scale 50A from RS 287-2059 £19.65 each.

When to stop charging by generator? Do you have wind and solar? If so, you want to stop charging with the genny when the solar can take over and finish the charging off right up to equalisation. I stop charging at about 15A to 20A and I have 560 Ah. If you don't have wind or solar then you are in a tricky situation as you are going to have to run the genny for hours every few days to finish off the charging. Best to get some solar if that's the situation.

 

[LadyInBed]

[ QUOTE ]
What happens if you over do it? Does it just labour and overheat the alternator, or does it trip?

[/ QUOTE ]
The hint is in the KVA - if you try to draw too much current, the supply voltage drops /forums/images/graemlins/frown.gif

 

[Chris_Robb]

Thanks Lemain - no we don't have wind or solar - but as soon as we set sail for foriegn seas - probably the Med, we will add solar cells.

I used to have a big Rutland on my last boat, but the regulator was so crap, it either boiled my batteries in a gale, or the voltage (again in a gale) was then set so low by Rutland, that it never exceeded 13.2V, and was dumping to the heat sink!. They had some 5 goes to set it before I gave up, and dumped the whole lot back on them. Things have probably moved on since then (1999), but I really could not stand the vibration created on the mizzen!