Running Washing Machines & Dishwashers on an Inverter.

Article 1.

Washing Machine Power Consumption

Modern washing machines are surprisingly energy efficient. If you are on a solar system and are shopping around for a new one, here are a few points to consider:

1) Buy one with hot and cold water connection and with a program whereby you can provide your own hot water rather than a unit that will heat the water with it´s own element!

2) The Star Label is a bit misleading if you are only considering power consumption and water usage is not a big issue with you. This is because the Star Label assumes that you are using electricity to heat the water. This means that washing machines which use a fair bit of water show a low star rating (due to all the water they are theoretically heating up).

3) Even though most washing machines only use 50-150 Wh/load (from our measurements of a few models), it still might need quite a large inverter, say 1200W, to power it for the few minutes while it is in spin dry mode, etc.

4) The Fischer & Paykel Smart Drive range use a DC type of motor which soft starts. They will normally work off a 600W inverter.

5) Most modern washing machines have a lot of electronics and need a sine wave inverter to operate. Don´t run them on cheap dodgy generators!

Some power consumptions that we have recently tested:

A) Simpson Ezi Wash 6.5kg used 106Wh on one full load. It has an AAAAA water rating.

B) Fischer & Paykel Smart Drive Excellence 7.5kg. This machine for our staff used 140Wh for a big load of one of our installers work clothes. It used 80Wh for a smaller load. It uses 240 litres of water on the lowest water setting.

C) LG 5kg. Model Fuzzy Logic WF-T502TH: This machine only used 36Wh on a small load and 54 Wh on a large load. It was observed to use 17-22W while filling; pulses of 160W while agitating; 35-60W to pump out; 23-54W while rising and 440W while in spin mode. My Energy Monitor 3000 showed a peak/surge wattage of 1443W.

A few measurements on older model units include:

D) Fischer & Paykel Smart Drive 600 Series 107 Wh/load.

E) Hoover Gemini 4kg: Used 110Wh/load and works off a 500W inverter

F) Hitachi 5kg - 10-year-old model - only used 50Wh per load and 150 litres of water

G) Asko 6 year old front loader used 90Wh per 'short' cycle. Maximum power was 600W.

H) A large 7kg Electrolux Ecovalve used 114Wh on the cold wash cycle & 360Wh with the temperature set at 60 degrees. Maximum power only 400W.

To summarize the results of all loads on all washing machines, the overall average was 85Wh/load.

If you would like to measure some power consumptions, buy one of our Energy Monitors! www.rpc.com.au/products/meters/meters.html

Article 2.

Running a LG 8013f on an Inverter
by Jonothan Rihan

Some front loaders have a high start up surge. This was borne out when we tried to use my mother in law's older front loader. It refused to start washing when connected to a 1200 watt inverter but runs fine on an Selectronic SE32 (2400w continuous). I suppose this is due to the power needed to start turning the drum full of wet washing.

The LG will run on a Selectronic SE22 inverter (at 12volts). This device has a maximum continuous rating of 1200watts. I don't have a smaller inverter here to try it on so could not say for sure how small you could go. I have measured most of the sensible cycles on the LG and can advise that the quick 30 program uses 36 watthours, a max power of 685 VA, a max current of 2.9 amps (AC).

The long cycle set on cold uses 135watt hours, max power of 812 VA, and current of 3 amps. Getting it to heat water to 30degrees makes quite a difference -259watthours, max power of 2170VA, and 9 (!) amps.

These measurements have been made with an Energy Monitor 3000 power meter. I have only had it (the meter) for a while and have to presume that the factory calibrations are accurate. Interestingly the washing machine has a constantly changing Power Factor ranging from unity at some points in the cycle to an awful 0.13 at others. One of the nice features of my meter is an indication as to whether a load is inductive or capacitive.

One of the major problems with using front end loaders with solar power systems is their propensity to heat the water internally. I am not aware of a way to override the internal heater and I have not yet managed to get the thing to use hot water straight from the tap. Swapping the hot and cold pipes over just means that the rinse cycle also uses hot water. Having solar hot water we have a surplus of suitably hot water but I wish I could find a way of feeding some of this water into the machine and not have to waste energy heating it.

The bosch washing machine saga has progressed - we had the generator tested by an electrical machinery specialist firm in Toowoomba. Their comment was along the lines of "Without spending a few thousand dollars more, this is the best you can get out of a gen set. It is one of the best sine waves we have seen from such a generator". They could not see why it would cause problems for the washing machine, and said that the sine wave definitely was not "clipped" (at one stage a Bosch technician said that this was likely to be the problem - but the other technician with whom we mostly dealt was pretty sure it was an example of an ongoing problem with Bosch washing machines).

The gen set is a Dunlite 2500L and we bought it (7 years ago) because it was said to have a good sine wave that would give no problems with electronic equipment. Apart from its total lack of problems with any other equipment apart from the Bosch machine it has been incredibly reliable - for quite a while it was our only source of power and was used for several hours every night.

After this gen set testing result was relayed to Bosch they advised us to approach the retailer (Harvey Norman) for a refund. Harvey Norman contacted Bosch and after discussing the problem with them agreed to a full refund.

We were told by the Bosch technician that this is a common problem with Bosch washing machines - "the complex electronics in the washing machines are not compatible with generators or solar power systems, without spending several thousand dollars to get a very good output from the power source" would be a fair summary of many discussions with him. He also asked one of their sales people whether there would be likely to be a model coming out that did not have these problems and was told that this would not happen in the forseeable future.

There is nothing on the Bosch website or in their warranty document that advises of this problem.

I think the lesson from this is that anyone contemplating buying a 4- star water or energy rated washing machine of any brand to use on generator or solar power, should contact the manufacturer to get a clear statement of its ability to run the intended power source.

I would like to point out that Bosch were nothing but helpful and open about all of this right through - and that the washing machine was a fantastically environmentally friendly item - 4 stars for both water and power, and did a good wash.

Gordon Claridge

Running a Dishwasher on an Inverter.

A Fisher & Paykel Dishdraw dishwasher used 380Wh per normal load on 'Eco' setting with a maximum power draw of 1200 Watts.

Dishwasher Test

In a normal Australian Standard test a particular dishwasher (made in China) used the following: Normal test: - Water inlet Temp: 20C +-2C 15.58 litres of water 0.971 kWhr/cycle

Hot Water Inlet Test:
Water inlet Temp: 60C +-2C
0.377kWhr/cycle
15.68 litres of water

Which equates to approx 354 kWhr/yr (cold water inlet).

That is using the appliance 7 times per week on the Normal Cycle.

The dishwasher had an energy star rating of 2.

And a water star rating of 2.5

Hot water inlet (60C) would equate to approx 137kWhr/yr

If you are connected to the AC grid, then at 15c/kWhr

354 kWhr/yr = $53.10

137 kWhr/yr = $20.25

A difference of approx. $32.85 per year.
Very significant when you add up the cost of running all your appliances.

 

Turning off the dryer heating to reduce power consumption.

One other thing our hot water feed is high pressure throughout our house.

Can you turn off the dryer?
Yes!
The program we used is called "Without Heater" which leaves thedishes to dry on their own. Weusuallylet them stand for about an hour or so inside the machine.

Contribution from Michael Laba

From observation most of the machines have a dry cycle which is a 30 minute period or so. This drying is done by the final rinse temperature.

During the final rinse the water is heated to a temp. of probably minimum of 45 Celcious, normaly 50 C, and then the machine will often leave that water in the machine to use as heat, and that somehow drys the dishes, there are some machines that have a fan in the front door to circulate the steam out of the machine, but it is rare to find a machine that drains the water before the drying cycle starts.

So from that you can gather that there are currently not many dishwashers that heat the air to dry the dishes. (there may have been some older dishwashers that did heat the air, this also melted the plastics). Therefore unless you take off the final rinse (generally 2 rinses after mainwash) you won't really gain much by trying to eliminate the drying cycle.

There are now machines with economy drying, and also economy heating during wash. But this is reflected on the Energy star rating (if tested in the economy mode). Some machines may have a program that dosn't include drying the dishes, but they are normally just rinsing cycles etc.

Also if you look in the instruction manual it will describe the cycle of the different machines.