b&q performance power generators

[Fred]

Hi,

I see there is a 2-stroke and a 4-stroke"performance power" generator reduced to clear at B&Q. Are either of them any good?

TIA

[Fred]

Sorry to reply to myself but I realised that my earlier post was thin on the ground.

Neither generator seems to be on B&Q's web site. They are cream in colour.

The 2-stroke is the typical 700ish Watts peak but does not seem to have the 12v output that some do. OTOH I think someone said it wasn't worth running a generator just to top-up a battery: something to do with it being a small load?

The 4 stroke is, I think, rated 2.4kW peak. I didn't have a proper look and was going to go back and read the box but if you don't think it's worth bothering with, I'll save my time an petrol.

I think both of them say "not for electronic devices". Why? I thought generator outputs were pretty clean?

I was looking for a small 2-stroke to keep the boiler going if the electric went off in this bad weather but I am wondering if the bigger

4 stroke would be more versatile and keep the TV on too!

BTW has anyone found the Auto express review of 2-stroke generators:

thought all 2 strokes were the same but they found the SIP sold by Tool station was not as good as the Wolf ones formerly sold by Screwfix and Aldi.

Why would that be? I thought they were all made by the same company and just painted differently.

TIA

[Peter Parry]

A lot of these magazine tests are carried out by asking the manufacturers to provide samples on loan. Some manufacturers prepare them better than others before handing them over. Even when they are bought usually only one is and the variation between individual samples of the same model of cheap generators is often considerable.

[Fred]

Is there much adjustment to be done? I thought it was just a matter of filling with fuel and pulling the handle?

Why is that? Don't they all have the same motors bolted to the same alternators, etc? If I buy one, let's hope I get one from a good batch rather than one of he poorer batches ;)

[Appin]

The message from Fred contains these words:

Far from clean and sometimes far from sine wave.

Voltage and especially frequency regulation is often very poor -- according to my electricity supply contacts it's the poor frequency regulation that kills the electronics in their experience.

[Peter Parry]

If you want one to do well you could rebuild the engine polishing out all the rough bits, select a generator with high output, check the regulator works properly etc.

Poor manufacturing tolerances and poor quality materials. The cheaper end of the Chinese manufacturing sector doesn't yet understand words like "consistency" so different components will be used randomly and many different sub-contractors parts used without any real quality checks. It is not for nothing that the useless "CE" mark is usually taken to mean "Chinese Export".

Oh yes - it's just that the "5HP" (or whatever) motor will produce anything between 1 and 4 HP and the alternator is good for a maximum out put of 100W, or 200, or 500 or some other pseudo random figure.

[Roger Mills]

A lot depends on the technology used by the generator - which, in turn, is reflected in the price.

Better - more expensive - generators produce DC which is fed into an inverter to produce AC - and these are *very* stable in all respects - voltage, frequency and accuracy of sine wave. Cheaper ones use AC alternators - whose output (voltage and frequency) is all over the place when the load changes.

[Fred]

Oh dear. So you really do get what you pay for in this case. I wonder at what point does something switch from electrical to electronic? When these generators say not for electronic devices, isn't everything electronic these days? I was thinking I would get the 4 stroke generator to power the freezer and the tv but now I am wondering whether to sit in the dark instead! I may just get the cheaper 2 stroke one and just run the boiler; at least we would stay warm. We haven't had any trouble yet but with the bad weather and reports on the news about people without electricity, it made me think. Once the snow melts, I'll forget about it for another year ;)

[Fred]

I was going to buy just in case of a power cut, which I hope is unlikely and infrequent occurrence so I can't justify buying a Honda for a once in a blue moon scenario. I thought a fifty pound 2 stroke might be worth looking at though.

[Andrew Gabriel]

Strange, I can't imagine frequency having any bearing on electronics.

[Roger Mills]

If you want an inverter-based generator without paying Honda prices, have a look at this one from Machine Mart:

's less than half the price of the equivalent Honda jobbie - but still a bit more than your £50 2-stroke model!

Bear in mind - if you want to be able to power your central heating electrics with it - that most boilers (except very old ones) have lots of electronics in them. I wouldn't risk using a very cheap generator with mine!

[Dave Osborne]

Well, a change in frequency would make a power transformer more or less efficient and would affect any real time clock which was deriving its timing from the mains frequency (unlikely I know in this day and age)..

But I would have thought that brownouts cause by changing load conditions would be generally more problematic than frequency variations.

[Andy Champ]

Switched mode PSU and quartz crystals in most modern gadgets...

Andy

[geoff]

In message , Andrew Gabriel writes

What about C-R dropper networks for providing e.g.24v where they are too pikey to use a transformer - widely used in central heating electronics

[Mark]

Yes even a secondhand Briggs+Stratton would be a better option at least you can get spares for them.?

[Andrew Gabriel]

Impedance of the C will change, but that's just [inversely] proprotional to the frequency change. A much bigger effect will be the capacitor coupling voltage spikes directly through to the low voltage side, so that a 20% mains voltage spike will generate of the order of 48V spike at the (probably crude) voltage regulator input. That's why I would guess dirty voltage would cause more problems, but it's not something I've tested.

[Fred]

I have an oil-fired boiler, if that makes any difference?

Perhaps I am better sitting it the cold for a couple of hours during a power cut rather than sitting in the cold for days because my boiler has blown up!

I found old threads about cheap and cheerful 2-stroke generators and they seemed to have been praised here before but now I am not so sure. If you rule out running anything with electronics in them, what is left to power?

This was only a knee jerk reaction because 5000 homes were reported to be without power because of the snow. Touch wood we haven't had a power cut for over a year, so I can't really justify buying an inverter genny that will probably sit unused in the garage for twenty months at a time.

[Roger Mills]

Dunno - I've no experience of those! What does it use electricity for? Does it have any electronics on a PCB?

Your choice!

Traditional light bulbs, heaters with resistive elements, maybe the odd electric motor as long as it isn't too fussy.

Again, your choice! But bear in mind that most local authorities have got very little salt for the roads because we haven't had a harsh winter for a long time. Climate change *could* result in more power cuts, even though we haven't had many of those in past years.

Maybe the thing to do is to wait until the summer, and then get an el cheapo genny and try your boiler with it. If it *does* blow up, you'll have time to fix it before next winter.

[NT]

Bad waveforms are very effective at kiling those. Resistor dissipation goes way up, and the magic smoke gets out

The biggest problem with electronics on gennies is voltage surges due to the gen being an inductive source. Other issues are low freq heating up transformers, and poor waveform greatly increasing dissipation in filters and crude power supplies.

NT

[Mike]

For what reason? The generators we built at school from coat hangers and a bit of enamelled wire produced near perfect sine waves!