Using a generator to power a washing machine

vtmaps · January 2013

Re: Using a generator to power a washing machine

BB. wrote: »

The big question here is what is the kW of the load--For a typical motor load it is not unusual for PF to be in the 0.67 range--But for resistance heating for it to be in the 0.95 to 1.00 range... That will affect the kWH per gallon ratings... For example using 0.67 PF:
8.9 kVA per gallon * 0.67 = 6.0 kWH per gallon of fuel

Huh? I thought that poor PF had very little effect on energy consumption. There will be a bit of increased i²r losses in the wiring, but that should not have a large effect on fuel consumption.

--vtMaps

westbranch · January 2013

Re: Using a generator to power a washing machine

the way I understand it is the Watts stays the same but VA's increase for the same load with a poor PFC,
ie for Off Grid it is important because we need to know what the batteries have to supply.
So for an Edison bulb there would be close to 100VA for a 100w light bulb,
but for a CFL that is rated as 23w it may consume 50VA due to poor PF.
so in BB's example it is more KVA that has to be supplied

vtmaps · January 2013

Re: Using a generator to power a washing machine

westbranch wrote: »

but for a CFL that is rated as 23w it may consume 50VA due to poor PF.
so in BB's example it is more KVA that has to be supplied

I agree that more VA needs to be supplied, but the VA is not really 'consumed'. A 23 watt CFL consumes 23 watts.

--vtMaps

inetdog · January 2013

Re: Using a generator to power a washing machine

vtmaps wrote: »

I agree that more VA needs to be supplied, but the VA is not really 'consumed'. A 23 watt CFL consumes 23 watts.

--vtMaps

Let's say to make the numbers easy that you are running your 23 watt CFL on 115 volt AC. That would be .2 amps if the load were purely resistive, the inverter would supply .2 A RMS on its output, the batteries would supply 23+ watts at DC to the inverter to handle it. The peak DC from the batteries, as opposed to the average DC would be (whatever it is.)

If the CFL had a .5 PF, then it would pull .28 amps at a 45 degree phase angle to the voltage waveform. The inverter would have to deliver .28 amps RMS and it would take still take roughly 23+ watts from the battery. The average current from the battery would stay the same and the peak current from the battery may go up by a factor of 1.414.

The reason that we need to know both Watts and VA is that some calculations will use one value and other calculations will need the other. For battery sizing, it is the watts. For wire sizing it is the VA.

vtmaps · January 2013

Re: Using a generator to power a washing machine

inetdog wrote: »

The reason that we need to know both Watts and VA is that some calculations will use one value and other calculations will need the other. For battery sizing, it is the watts. For wire sizing it is the VA.

And to get a little closer to being on topic:
for generator sizing it is the VA and for gasoline consumption by the generator it is the watts. --vtMaps

NWCabin · January 2013

Re: Using a generator to power a washing machine

There's a lot of good information that people have shared, and I wanted to post an update. How ended up running things was to get a washer that I could run off of my inverter. My inverter is the MorningStar Suresine 300 and the washer is one of the Haier 1.0 cu ft washers. It's about a half of the size of a normal washer. For example, you can wash 3 pairs of jeans in it at a time. With the SureSine, I can power it, and when it agitates and spins it will draw the most wattage, so I need to watch what else is running at the same time, or it will overload the inverter and cause it to reset.

For the generator, I still don't have the budget to get something nice like a honda 3000 with autostart. Having something like that set up in a generator shed to be triggered by a battery monitor like the LinkPro would be a really great setup. Right now hauling my $299 propane powered generator out and pull starting it is pretty chilly work but not expensive.

BB. · January 2013

Re: Using a generator to power a washing machine

Just to be clear--A Honda eu3000i is not really configured for auto-start. It has a manual choke. People have configured to autostart by using a solenoid to pull the choke during starting. Also folks have configured them with remote start--basically a key fob with start/stop/manual choke control buttons (not sure about Honda, but have seen Yamaha and others with wireless remotes).

The smallest genset I have seen here so far that can be (more easily) configured to auto-start (automatic choke) is probably the Honda EM4000SX that Chris Olson is using. The choke/mixture is controlled by the electronic engine controller.

-Bill

NWCabin · January 2013

Re: Using a generator to power a washing machine

Thanks BB, I didn't know that.

Are there any small wattage generators that come configured off the shelf to autostart? In my system, the only purpose the generator has is to run the battery charger when there have been too many overcast days in a row. I don't really need the 3000 or 4000 watt capacity. Or maybe I do, and someone will share their generator/charger/battery bank size combination.

BB. · January 2013

Re: Using a generator to power a washing machine

NWC,

I kind of got lost here--Exactly what is the battery bank configuration (AH, 12/24/48 volt, series/parallel, flooded cell/agm, etc.).

And what brand/model of charge controller are you looking at?

If your system is configured/purchased/installed, if you can add a signature to your profile and "turn on signature" (next post, go to Advanced Editing and click on "show signature" check box)--It would keep things a bit more focused.

http://forum.solar-electric.com/profile.php?do=editsignature

-Bill

ChrisOlson · January 2013

Re: Using a generator to power a washing machine

BB. wrote: »

The smallest genset I have seen here so far that can be (more easily) configured to auto-start (automatic choke) is probably the Honda EM4000SX that Chris Olson is using. The choke/mixture is controlled by the electronic engine controller.

I'd like to point out that the little 46538/46539 Champion generators also have an auto-choke and I have mine configured for auto-start with the Trace/Xantrex GSM on the SW Plus inverter. When our Generac would fail to start in cold weather I used the Champion as a backup with the auto-start and it works fine.

It is basically a three-wire start generator and you only have to tap into the wires on the back of the Combination Switch to do it, which is quite easy to do.
--
Chris

BB. · January 2013

Re: Using a generator to power a washing machine

Neat--Now two "small" AC Generators that can be configured for auto start.

-Bill

PS: Added above information to the Working FAQ thread, generator post:

http://forum.solar-electric.com/showthread.php?5556-Working-Thread-for-Solar-Beginner-Post-FAQ&p=133095#post133095

ChrisOlson · January 2013

Re: Using a generator to power a washing machine

BB. wrote: »

13.6 hours * 3.8 kVA / 5.75 gallons of gas = 8.9 kVA per gallon of gasoline

The big question here is what is the kW of the load--For a typical motor load it is not unusual for PF to ge in the 0.67 range--But for resistance heating for it to be in the 0.95 to 1.00 range... That will affect the kWH per gallon ratings... For example using 0.67 PF:
8.9 kVA per gallon * 0.67 = 6.0 kWH per gallon of fuel

I can provide an update on the fuel consumption numbers of the Honda EM4000SX now. I bought an hour meter for it, because it didn't come with one from the factory. I kept track of all my fuel slips every time I bought gas for it for the whole month of December, and now that we are into cold weather I expected the fuel consumption numbers to be better (due to the cold dense air). Turns out it wasn't.

We burned 51.48 gallons of gas in the Honda for the month and clocked 107.2 hours. So the fuel consumption, on average, was .48 gal/hr. The loads are a little harder and I can only estimate them. Roughly 90% of the generator hours is for Load Amps. I have the maximum amps set to 31 and the charger amps set to 30. When it runs for Load Amps it typically runs at full load because the inverter won't start it unless the amp draw on the inverter is over 40 amps. But it also ran 10-15 hours for battery charging during the month, and it doesn't run at full load during battery charging. So coming up with an average kVA output is hard to do being I don't have a kWh meter on the gen's output.

My best wild guess would be an average output for the whole run time during the month of December of 3.5 kVA. So 375 kWh and 51.48 gallons of gas figures out to 7.28 kWh/gallon. The price of gasoline for just about the whole month was $3.29/gal here. So it cost us 45 cents/kWh for gen power for the month. That's really darn expensive compared to what power from the grid would cost - especially considering that roughly 33% of all our power for the month came from the generator.
--
Chris

icarus · January 2013

Re: Using a generator to power a washing machine

ChrisOlson wrote: »

I can provide an update on the fuel consumption numbers of the Honda EM4000SX now. I bought an hour meter for it, because it didn't come with one from the factory. I kept track of all my fuel slips every time I bought gas for it for the whole month of December, and now that we are into cold weather I expected the fuel consumption numbers to be better (due to the cold dense air). Turns out it wasn't.

We burned 51.48 gallons of gas in the Honda for the month and clocked 107.2 hours. So the fuel consumption, on average, was .48 gal/hr. The loads are a little harder and I can only estimate them. Roughly 90% of the generator hours is for Load Amps. I have the maximum amps set to 31 and the charger amps set to 30. When it runs for Load Amps it typically runs at full load because the inverter won't start it unless the amp draw on the inverter is over 40 amps. But it also ran 10-15 hours for battery charging during the month, and it doesn't run at full load during battery charging. So coming up with an average kVA output is hard to do being I don't have a kWh meter on the gen's output.

My best wild guess would be an average output for the whole run time during the month of December of 3.5 kVA. So 375 kWh and 51.48 gallons of gas figures out to 7.28 kWh/gallon. The price of gasoline for just about the whole month was $3.29/gal here. So it cost us 45 cents/kWh for gen power for the month. That's really darn expensive compared to what power from the grid would cost - especially considering that roughly 33% of all our power for the month came from the generator.
--
Chris

Thanks Chris,

This post might be waved in the face of all those that think that pie in the sky, going off grid to save tons of money from corrupt
utility companies is a good (financial) idea,

Take a hint guys,,if it was cheaper, then everyone would do it!

Tony

ChrisOlson · January 2013

Re: Using a generator to power a washing machine

icarus wrote: »

Take a hint guys,,if it was cheaper, then everyone would do it!

Yep. When you start running washing machines or clothes dryers, etc with a generator - it can be done for off-grid but it's not cheap no matter what you do for a generator. The difference between a tiny generator and a bigger one with more capability is usually so small (in operating cost) that buying an under-sized generator is not a good idea either. December and January are the worst months of the year for us, traditionally, and we've gotten used to that. For a part-time off-grid cabin, running these things with a generator is not really that bad when you consider the location (and why it's off-grid because of the location), and you have to accept it in trade for being able to enjoy your off-grid cabin. When you live off-grid 365 days a year it's a little different and you have to do things to make it as efficient as possible and still be able to live a fairly comfortable lifestyle.

From our own standpoint we've made huge strides in being able to enjoy the things that people on grid power have. But the generator is a big part of being able to do that. Without the generator we'd be living pretty meager here. I've spent lots of money and swapped out inverters twice in the last three years to have a setup that is more efficient and ultimately burns less generator fuel. And there's no real "manual" you can refer to on how to do this - it's all seat-of-the-pants experience and what works best for you.

When I look at this thread from a practical standpoint, I see nothing inherently wrong with running a washing machine with a generator to save on sacking the batteries for an off-grid home or cabin. But the first choice of the OP with that little generator, I think, is a bad one. It would be bare minimum. And when you look ahead to the future things always tend to get expanded, or add things to your system. My "mission" is tell other folks how NOT to make the mistakes I have made with some of this stuff.
--
Chris

ChrisOlson · January 2013

Re: Using a generator to power a washing machine

My wife put a load of clothes in the washer and I happened to see the load amps on the inverter panel so I took a video of it. We were actually on gen power at the time, with the generator running on the countdown timer on Load Amps due the dryer running, but at the end of the cycle in cooldown.

But this is what the washer does to the load amps:

[video=youtube_share;zGTtmN0stzs]

http://youtu.be/zGTtmN0stzs[/video]

That would wreak havoc with a little 1.2 or 1.4 kW generator with a mechanical governor. The governor would be worn out and shot inside 6 months, and I suspect with a little generator there would be some pretty serious surging. I also put my Fluke meter that has high point capture in it on the line to see what the motor in the washer draws during surge when it starts on spin cycle. 22.7 amps.
--
Chris

Using a generator to power a washing machine

Comments

Categories