Just had this enquiry come through and I thought it might be quite widely relevant so I have posted it here for your consideration. Please come back with any thoughts or personal experiences on the subject. Heres the question I received via email:
Would you mind if I asked you a quick question?
We’re wondering if we can use a more modern washing machine within our current marine set-up:
We have a Honda Eu20i, Victron 12/1200/50 Phoenix MultiPlus Compact Inverter and 2 Victron domestic batteries. We’d like to be able to use this Hoover w/machine which only has a cold-water fill, which uses 1.02 kwh. http://www.appliancesonline.co.uk/product/ophs612-hoover-washing-machine-white-22127.aspx
Do you know/think this is a possibility for us? We’d only be using low temp programmes, but gather that is insignificant to peak power?
Thanks is advance for any help you can offer us on this.
And here’s my answer:
A washing machine is to some extent an inductive load in that the motor starts up under load and will therefore draw more power for the first few seconds than it will once it’s up to speed. Thankfully washing machines are very high geared so the starting currents are much less than for many electric motor applications .The 1kw rating will probably relate to its consumption after the motor has started and its starting current could well be a multiple of this.
It very much depends on how much of the 1kw relates to the motor and how much to the heater element inside the drum. I couldn’t see any clear indication of this and it could be that the 1kw relates to just the motor consumption or that it’s a combination of motor and heater. Certainly I would have expected the motor to be in the 1kw range and for the heater to be a further 1kw or so. It may well be that the starting power exceeds the max 2kw rating of an EU20i but this is not necessarily a problem as long as the generator is able to respond and get the motor starting within a second or so or the same sort of time it takes to start on the mains. If the generator takes longer to get the motor started than the mains then there is a danger of cooking either the motor or the generator as the motor will be spending longer in the start-up phase than it is designed to. When the motor starts it is effectively just a heater element until it starts spinning and the fan starts shifting air through it.
You will almost certainly need to turn the ECO throttle mode off in order for the generator to respond rapidly enough to the load from the motor. If you have ECO throttle on then the generator will take too long to react and endanger the motor of the washing machine. If the generator struggles and starts vibrating a lot without quickly recovering then it’s not going to work out. I would contact Hoover and ask them the specific power of the motor and the heater separately.
One other issue you may come up against is that washing machines are often designed to run specifically on domestic mains supplies where the earth and neutral wires are tied together (referenced to earth). Portable generators are not wired like this for safety reasons and there is no connection between neutral and earth. This can lead some washing machine controllers to become confused about the supply. The solution to this is to tag the earth and neutral together as in domestic wiring but it is very important to make sure you have a good earth connected to the generator. In a boat this should be easy as you can pretty much earth to the hull if it is steel. You might want to consult an electrician if you find you do need to do this. I would try it without first anyway.