# What Size Generator will i need to run my Karcher HD 6/13



## sevv (Jan 14, 2013)

Hi 

I wonder if anyone can help me 

I have a Karcher Hd6/13 Commercial pressure washer and i would like to know the minimum size generator i will need to run it properly as i wish to do mobile valeting

i am really confussed as a few people tell me different things as it has a max load of 2700w but in the start up it nexts extra power 

some people have told me 20% extra an additional 540watts some say 2-3 times the 2700w 5400+ watts 

please could anyone help as i am really confussed 

does anyone have a karcher Hd 6/13 that they are using on a petrol generator is so what sie generator do you have 

i appreciate anyone advice 

thank you


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## AllenF (Aug 20, 2012)

Its complex math
What is the plate on the motor saying.2700watt is 2.5 hp thats going to roughly need three times that to start it so your going to be looking at about a 6.5or7kv gennie mate not gonna be cheap.


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## Azonto (Jul 22, 2012)

You would be 100000000000x better off investing in 3 or 4x 50m extension cables, and for those cars that will be valeted in the middle of a field, I'd suggest moving them first..


Or if you must have complete mobility, I'd recommend picking up a much smaller jet wash for use with generator


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## sevv (Jan 14, 2013)

thank you for your help so would a wolf pro wp7600 6500watts /8.75kva 14hp be suitable to run it


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## Mark Chandler (Nov 7, 2011)

I have a 3hp compressor, it ran well on a 6.6Kw 'silent' diesel generator, I started off with a 4.5Kw which went back the same day as it could not start the compressor so was forced to upgrade.

Silent it was not, cost around £800, when I added 300 watts of lights the compressor started to struggle to start, once it was spinning over it was fine.

Based upon this what you are suggesting will be perfect, it will however be very heavy. It's the high load to start that's the issue so I suggest you take you PW to the machine seller and try in the first instance.

It was also remarkably cheap to run on red diesel.

Would you not be better off looking at a lavor PW with a 5.5hp Honda engine, much lighter and cheaper.

Regards Mark


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## carfix (May 28, 2010)

Don't take this as gospel lads, but the reason that you need 3 x the power to start a Compressor with a genny, is because you have to get over the inherent spike caused by the back pressure of the compressed air in the cylinder already. 
I got by as a pauper smart repairer for a few years by starting a 2hp compressor with a 2.3 hp genny ( £250 from Macro) as i used the dump valve ( nearest i'll ever get to a Scoobie) to drain the tank when i needed to fill up with more air. If the Karcher doesnt have backpressure, do you need the extra power to get over whatever inertia may be present ? What we need is a good leccy to tell us.


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## Topman c (Feb 8, 2013)

*hi*

you will need a honda 5.5- 6 kva hondas electrics are equivalent to 10 kva i got 
a honda eu65is will run everything


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## Bero (Mar 9, 2008)

carfix said:


> Don't take this as gospel lads, but the reason that you need 3 x the power to start a Compressor with a genny, is because you have to get over the inherent spike caused by the back pressure of the compressed air in the cylinder already.
> I got by as a pauper smart repairer for a few years by starting a 2hp compressor with a 2.3 hp genny ( £250 from Macro) as i used the dump valve ( nearest i'll ever get to a Scoobie) to drain the tank when i needed to fill up with more air. If the Karcher doesnt have backpressure, do you need the extra power to get over whatever inertia may be present ? What we need is a good leccy to tell us.


That's not the biggest reason, when you switch any electric motor on there is a spike of current to get it moving, before it settles down to operating current. Similar in theory to giving something a big push to get it moving, and a lot less force to keep it moving.

That's why circuit breakers in your house/industry have different sensitivity (B,C and D) ratings depending on the circuit and if there will be motors on it. For example a 10A MCB with a 'D' rating will not trip untill a spike reaches 100-200Amps! A 10A 'B' rated MCB will trip with spikes greater than 30-50 Amps.


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