Hi All
I'm Thinking of purchasing the Wolf Power 720 Watt Generator from Screwfix for £79.99...I would appreciate if anyone can tell me what you can run off it....My requirements would be a fridge freezer, telly and a couple of lights in the event of a power cut... Thanks in Advance Cal.
That all depends on the power consumption of said fridge freezer, telly and a couple of lights! :-)
You need to take a look at the labels and/or instruction books for the TV and the fridge/freezer and that should give you some sort of indication of the power consumption. Add the totals together, plus the lamp wattages and, if they add up to less that 720 watts you're OK
- maybe.
The issues that may affect this are:-
The fridge/freezer will take its power in 'lumps', quite a bit of power when the compressor is running, none at all virtually when it's not. In addition the compressor start-up load may be too much for the generator to cope with. A 720 watt generator may simply not be big enough to run the fridge/freezer even though the average power consumption is well within the generator's capability.
The TV will probably take rather less power than the label indicates, in addition it probably won't have much of a start up surge/inrush.
The lamps will have a significant inrush current but this really shouldn't be a problem as the result will simply be that they start up somewhat slower than they would on 'real' mains.
Do you really need the generator to run the fridge/freezer, it takes many hours for contents to warm up dangerously, espcially if you minimise opening the door as far as possible.
This is quite likely to be the show stopper, especially of there is a couple of hundred watts of load for the telly and few lights already on it. A typical motor needs 2 to 3 times it's rated power to start, so a 150W fridge freezer (ball park) will require at least 450W. OK in theory that is well within a 720W genny but these things are made down to a price and the spec might be optomistic. Not to mention that this is a sudden load rather than a gently increased one or steady state. The engine could stall or slow so much that the volts drop to low for anything to happen.
The only way to find out is to try it I think.
Depends where you are, power cuts here are measured in seconds or
come out and fix it. I suspect if the 1/2 mile or so of line feeding just us came down in a storm we could be without power for *a lot* longer...
Just to add insult to injury, the fridge compressor will almost certainly be powerd by an induction motor which will present an inductive load to the genny. If the genny is rated at a genuine 720W you may be ok, however you may find it is rated at 720VA, and hence the poor power factor of the fridge will eat even further into its available output.
A freezer should be good for at least 24 hours, if you keep the door shut. Enough time for the shops to open, so you can rent a genny?
It'll last longer, and use less power, if you keep a darn great lump of ice in the top - our Bosch even came with some plastic bricks full of water for just this reason.
Andy
I have one of these. They're good, but not great. The engine's ok. The output isn't exactly clean, but it's fine for emergencies.
It'll power your TV and lights with no problems. As for the fridge, it really depends on the fridge. I used it to run a 400W jigsaw, so it will run motors, but depends on the motor.
BTW, if you're anywhere near Devon, mine is up for sale.
If the storm has bought the line down and, if the MetO are to be believed re a cold winter, there is a good chance that we won't be able to get to the shops 20+ miles away as the roads will be blocked... We get cut off at least 2 or 3 times per winter.
Both of our freezers also came with big cold blocks. They are both A rated as well, in the last power cut of 8hrs or so the one with the temp display had got up to -12C from -24C. OK not thawed but in another 16hrs?
TV and lights should be no problem. Both eat large surges at switch on, but for a short enough time not to dog the genny down.
Fridge freezer is another matter. The prime problem is that the fully loaded induction motors need a pretty large power surge to get running, and I doubt the gen could provide that. If you had one its worth a try, but I think quite likely it wont work. You can expect a lot more tban
3x surge current, it may be as much as 10x or more.Realise the Vout will drop during this surge, and this is known for frying fridge compresors.
Same is true for tvs: portable gens produce some large surges when loads switch off (eg thermostatic fridge), and electronic supplies are not necessarily capable of surviving them.
Also be aware that gnerators are rated in VA, not watts, and the VA rating of any motor is greater than its wattage rating.
If for some odd reason you were real determined to run a fridge compressor off a small gen, I'd suggest either using a motor generator set with flywheel, or, giving less capacity, bolting a damn big flywheel to the wolf gen.
NT
Makro are selling an 850 Watt genny for 39-99 + Vat, if any one is interested.
Dave
TV and lights should be no problem. Both eat large surges at switch on, but for a short enough time not to dog the genny down.
Fridge freezer is another matter. The prime problem is that the fully loaded induction motors need a pretty large power surge to get running, and I doubt the gen could provide that. If you had one its worth a try, but I think quite likely it wont work. You can expect a lot more tban
3x surge current, it may be as much as 10x or more.I run with a 6kva unit during mains outtages, and with TV / Lights etc on, when the fridge fires (ok so its a large amercian style one) up there is still a very noticable drop in voltage and the engine feel quite a hit.
I would say that instantaneous statup load is 8-10x normal running current simply because the motor is starting against a load and with the unit stationary, its virtually a dead short to the supply.
One of those 'joke'VA Wolf et al gennys wont have a chance with a compressor type load.
Tim..
They had somw 1.8kVA diesel ones a while back as well - that sounds like a more useful output.
That does, and all my other garden machinery is diesel. A 1.8kW generator would run my electric chainsaw among other things, and the hedge trimmer.
You can't remember how much the diesel generator was can you?
It was a SIP model IIRC, about £160 perhaps... I did not look that closely, but noticed a number of folks buying multiples of it at a time.
No doubt running on red rather than road diesel as well...
It might, see the previous caveats about starting motors. The lecky chainsaws I have looked at are rated around 1.5kW. OK so it's not starting under load like a fridge or compressor but...
Look on e-bay then...
I had a look today (had to pop in for more paint!) They had two different ones there at the mo, a NuTool 1kVA one that I did not look at closely, and a SIP Medusa 1kW. The SIP was £129 + VAT - but I think that was a petrol and not a diesel.
It's worth noting that a modern freezer should keep things frozen for ~24 hours if the door is kept shut.
sponix
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