I have bought a 4 stroke genny from good old Nettos for under a 100 quid.
I am about to test it on powering up my house in the event of the next power 
failure (of which we have many and prolonged...the last one was over 12 
hours!).
Other than a limit on th current drawn by things like kettles, cookers, hobs 
etc how do the switched mode power supplies within user equipment like TV's 
PC's videos, DVD's cope with a genny?...that is always of course providing I 
limit the power drawn to the stated max of the genny.
I was thinking in terms of frequency control, or any harmonics which may be 
there or spikes.
Anyone got experience of what not to connect to the generator please?

biggirlsblouse wrote:

> I have bought a 4 stroke genny from good old Nettos for under a 100 quid.
> I am about to test it on powering up my house in the event of the next power 
> failure (of which we have many and prolonged...the last one was over 12 
> hours!).
> Other than a limit on th current drawn by things like kettles, cookers, hobs 
> etc how do the switched mode power supplies within user equipment like TV's 
> PC's videos, DVD's cope with a genny?...that is always of course providing I 
> limit the power drawn to the stated max of the genny.
> I was thinking in terms of frequency control, or any harmonics which may be 
> there or spikes.
> Anyone got experience of what not to connect to the generator please? 
> 
> 

Modern electronics with switch mode supplies take the input and 
immediately turn it to dc - so won't generally care about frequency or 
harmonics and are pretty excellent at dealing with spikes too.

Of course, things like electric clocks will not have the same accuracy*.

Things like motors with high starting currents may trip the genny whilst 
trying to get up to speed.

*Some modern (typically "lightweight" models) genny often generate at 
high frequency, convert to dc and have an inbuilt, crystal-controlled 
inverter for producing mains frequency output. These vary prime-mover 
speed in response to load but keep their output frequency very accurate. 
They use much less fuel on light loads than a normal genny. Much cheaper 
to run, IME.

If you are planning to be out for hours, regularly, it may be worth 
considering getting a couple of big deep discharge batteries and a good 
charger and inverter. You then only run the genny on full load 
(supplying the household load and fast charging the batteries). Then 
have periods of blissful silence when the household load is being met 
from the batteries alone. Typically, you can run the genny for an hour 
and then have 4 hours running off the batteries - but it does depend on 
batteries, loading, etc.

One problem with a small genny is the waveform tends to not be a 
"perfect" sinewave but has a flattened top and bottom.

If you run the house off a battery bank and inverter, you will find that 
the inverter's inbuilt charger section performs very badly off a small 
generator. They usually are designed only for running off mains supply 
when it is available. It typically needs a 6kW genny to run the inverter 
and charge the battery bank, even when you are only loading it to 1.5kW.

Buy an inverter/charger designed to run off a small genny or get a 
separate charger meant for the purpose.


HTH
Sue