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Using Generator as electric hook up problem.

I have purchased a Generator (Clarke FG3000/2.8kva), to use via my elctric hook up socket. On the boat i have a sterling iverter/charger(1600watts) which the hook up passes through and the inverter automatically recognises if it's the engine charging the batteries or whether it's on the hook up.
My problem is that when i connect the gen to the inverter it switches to "shoreline power and fast charge" for about 10-20 seconds and then switches off to drawing power straight from the batteries and then back to "shoreline power" and so forth, when it switches to "shoreline" you can hear the gen go under load and then off, in time with the inverter. Do i need to buy a special generator for use with the inverter ?
The generator does run 230volt appliances if plugged directly into it and powers them fine, it only plays up when i try to use it as my shoreline power.
I don't like to run my engine every day to charge my batteries and use the inverter for my 230 volt equipment, which is why i have bought the generator. Thanks for taking the time to read this and all advice is gratefully received. Lee.

Asked by: Lee Farrell  | 7.25pm, Sunday 14 February

WW says:

It does sound like the voltage- or possibly more likely, the frequency- of the generator is changing when under load, which is confusing the electronics in the combi unit.
The sudden demand for power might cause the generator to "dip", and this can be enough to cause the combi to revert to battery power (ithe charger then assumes that there is something wrong with the mains supply to the combi).
Most simple petrol generators only have a very basic control of the output voltage and frequency- as the throttle is just set to one speed, and the control of the generator output is purely based on the RPM of the generator.
More expensive/complicated generators, actually produce electricty that is of a purer waveform and frequency than from the mains supply- they use an inverter to ensure the voltage/frequence are maintain within strict parameters.
If you have access to a SUITABLE multimeter (or a friendly electrician) then you can check the AC voltage (which should be 230V +/- 10V) and the frequency (50Hz +/- 5 Hz). If it changes dramatically when the combi is plugged in, then this might be the cause.
if not, let us know!

Mark Langley  | 2.02PM, Monday 15 February

Readers say:

As an ex electrician (although not a marine expert)I have to ask Lee why is your invertor wired thru your mains hookup ? I have a small invertor on the narrow boat i have just purchased.
I have the manual on the installation and it takes both the battery leads to its connection terminal.There is no mention of passing the electric mains hook up thru it at all.

edward Connolly  | 3.40PM, Monday 1 March

Firstly thanks to WW, i have had the gen sent back to the manufacturer who tested it and say all is ok. I've also taken the circuit from the inverter back to Sterling in Droitwich who done a free upgrade for me, which allows a greater frequency tolerence but this has not helped. The issue is just that the gen won't produce the pure sine wave needed to power the inverter. I should have bought an inverter generator but need at least a 2.0kva unit which are very expensive.
I've been advised that an "auto voltage regulator" may help resolve the problem but it's not the voltage, it's being able to maintain a stable frequency that's the problem.
Secondly, Edward my inverter is a combi unit which not only gives me 230v but charges my batteries directly from the shoreline power hook up too. As i have a washing machine aboard which is digital and a microwave, they need pure sine wave. i would guess that your inverter doesn't charge your batteries when on shoreline power?

Lee Farrell  | 4.36PM, Monday 1 March

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