Solar to run a fridge.

Skippy · September 2016

Thanks for the reply bill.

I am really having "fun" with this washing machine - inverter combination. It appears that the motor may have a short in it.

Here is the story.
Had a friend over who also likes to "tinker" with solar stuff, and went to "show" him how the inverter would fault out . . . loaded up the washer, and when I pulled out the switch - it started right up !!
So I pushed the button back in, pulled it out again, and again - it started right up !!
O.k. fine - let the thing run thru the cycle - when it stopped to start the spin cycle - beep beep beep ......beep beep beep - it faulted out the inverter. Pulled out the manual, and yes, three beeps in a row means low voltage protection....
We all agree that the #6 wire is too small for this inverter, so we shut it all down, changed all the wires in the circuit to #4 AWG, and restarted it.
Pulled out the button to start the spin cycle, and the inverter faulted out again . . . beep beep beep beep beep . . . beep beep beep beep beep....
Pulled out the manual again, and five beeps in a row indicates a short circuit protection . . . so, my buddy asks "is the inverter grounded? " - no - so we took a few minutes, and ran a ground wire to the inverter.
Pulled out the button again, and it faulted out again . . beep beep beep . . . . . beep beep beep . . .
Back to low voltage protection . . . so we both figured that since the washer ran the first two times we started it - no problems - there must be a fault or short circuit in the motor itself . . . if it stops in just the right spot, it will start again on the inverter, if it stops on the faulty section - beep beep . . . since this machine has always been plugged into dumb old a/c power - it just powers its way thru the short regardless . . . now that it's plugged into an intelligent inverter - it senses a problem, and shuts down . . .

So, I have upgraded the wiring to the big inverter to #4 AWG, and just to check to make sure, we plugged in my microwave oven, and for a short time (1 min. or so) it was drawing 1,100 watts at 12 amps (at 12:00 noon - nice sunny day) .... did not want to stress the batteries too much, so I pulled the plug.... the inverter works....

So, whenever I have a problem starting this 30 year old washer, I plug it into a/c - turn the motor a bit, and then plug it into solar.... then it runs fine . .. until the next restart . . . then it's a crap shoot . .

Now to make the grounding more permanent . .

What do you guys think ? 1 green wire - inverter to inverter to tristar ? I know there is a grounding lug inside the tristar . . . Will have to check for more info on this one . . .

Oh ya bill, I have all my fuses and breakers on the hot wire, nothing is hooked up to the negative wires . . . . not a very good picture of the layout . . . should I be grounding the negative on the batteries ?

Skippy · September 2016

Just found the info.

Use copper wire to connect the grounding terminal in the wiring box to earth ground.

Can you translate this next part ? :

Do not connect the system negative conductor to this terminal. NEC requries the use of an external ground fault protection device (GFPD).

I know that the 1,000 watt - PSW inverter has a ground fault circuit in the plug, but I don't think the large inverter has any ground fault protection . . . and I certainly won't be wiring any wires inside the CC to that lug . . never heard of a GFPD though . . .

????

jonr · September 2016

Note that motor start surge is highly dependent on exactly where in the 50/60 hz cycle the switch closes. If the problem is random, I'd blame it on this.

mike95490 · September 2016

The batteries themselves may not be able to sustain the starting current required.

A 1Kw inverter is pretty small to try to run a large motor with.

manich · October 2016

Just wondering if the EnergyGuide tags that come with new appliances can be accurately used to figure a demand on a solar setup. I just recently replaced my "basement beer fridge" with a 3.1cf 220kWh/yr compact Frigidaire. If I divide that by 365, I get .603 kW per day. Is this a correct assumption? I bought this fridge in case I decide to expand my (2) 100w panels>120aH battery> 600w psw inverter in the future. Right now my system is just for rving and grid down events running just electronics and led lights, maybe 300w. Wonder how much I would have to expand to handle this little fridge?

petertearai · October 2016

here in Newzealand , the kw per year is conservative. My fridge uses about the rated energy for the first 12 hours after start up.
But once running it comes in under .

Skippy · October 2016

jonr said:

Note that motor start surge is highly dependent on exactly where in the 50/60 hz cycle the switch closes. If the problem is random, I'd blame it on this.

You may be right . . . I am going to have to do more laundry . . I just did two loads on fri . . the first load faulted out on almost every restart - even tried to do a restart by turning on the inverter while the machine was turned on - by using the inverters "soft start" function . . still faulted out . . . while the second load only faulted out one out of 4 .. . . and that one time the soft start worked !

Then yesterday, I did a load of laundry, and it did not fault out once.

I am starting to think that the motor may have a "dirty" spot on it, and the more I play with it, the more it wears thru and makes contact . .

Keep you guys updated.

Skippy · October 2016

mike95490 said:

The batteries themselves may not be able to sustain the starting current required.

A 1Kw inverter is pretty small to try to run a large motor with.

I tried to run my microwave which is 1100 watts @ 12 amps - and it started fine. don't really think it's the starting current.....

I did try to run the washer with the 1 KW . . . and your right - it won't run the washer - the "small" 1 KW inverter is just for the fridge - that is why I am using the large 2.5 KW inverter for the washer .. .

Skippy · October 2016

manich said:

Just wondering if the EnergyGuide tags that come with new appliances can be accurately used to figure a demand.....

Unfortunately, I threw that little yellow tag out years ago . . .

Good question though....

Re-did your math for ya, and your right - 220 kwh divided by 365 gives you .603 kw per day - your fridge is using about the same as mine with the foam all over it . ..
Now to get a kill - a - watt meter and plug it in for a day and see what it actually uses . . .
Then go from there. If the meter reads the same as the tag - then yes you can . . .

Skippy · October 2016

petertearai said:

here in Newzealand , the kw per year is conservative. My fridge uses about the rated energy for the first 12 hours after start up.
But once running it comes in under .

Please explain .. ?

If you take the rated usage per year and divide by 365 you get per day usage - what is your per day usage ? Do you have a kill-a-watt meter ?
The fridge cycles several times per day - every day - depending on how often you open the door of course.

Skippy · October 2016

Worth its weight in gold !

BB. · October 2016

Summer/Winter Room temperature (and probably humidity), how often the doors are open (the teenager factor), how often do you put room temp food in from shopping, do you make a lot of ice, do you clean the condenser coils, how old the fridge is, is the insulation water logged, etc. all matter.

For me, the "yellow energy star" tag is conservative--But I live in a moderate climate. I believe, the numbers (in US) are for a 95 degree room and a few door openings, no ice making (at least it seems to me).

I guess the procedure for testing is in here somewhere (after going through a 100 pages of gov.talk, I gave up):

https://www.law.cornell.edu/cfr/text/10/part-430/subpart-B

-Bill

Dave Angelini · October 2016

Definately agree Bill. Our 3 year old 22 cubic foot Whirlpool was rated at 1.3 KWH and the next year when Energy Star testing was changed the US went up to 2.2 KWH but the canadian useage stayed the same. I had a client buy one because of the bottom freezer and she measured about what I was getting on the same model.

petertearai · October 2016

when i turn on the fridge after arriving at holiday home , I measured the usage for the first 12 hours or so . this related to to enery star rating .( measured by a kilowatt meter) . once the temp gets down to the fridge set temps the power usage goes down . Of course as bill says depends on the ambient temp and how often the door is opened and what is put in .

mcgivor · October 2016

Much like EPA fuel consumption figures, they are based on ideal conditions, hence a guide. Inverter refrigerators are by far the most efficient and despite being common in most countries where electricity is expensive, they are apparently not readily available in the U.S.

My Panasonic, model nrbw415v, 400 liter total with bottom 124 liter freezer when compared to the same model without inverter, uses 40% less energy. To add to the benefit the compressor soft starts thereby virtually eliminates inrush current.

Two things to remember.
Good not cheap and cheap not good.
Figures lie and liars figure

Dave Angelini · October 2016

There is one more thing on my list. Never be among the first to buy something that is really important to you!

There are a few inverter compressors in the US/Canada. The LG 22 cubic foot is on my list but I will not buy one until there are technicians who are trained with the refrigerant they use. I know of 2 warranty cases with Samsung where they gave the customer their money back and they bought another brand without R600a. The linear compressor has a 10 year warranty but there were leaks in the systems and anyone who has reapired refrigeration leaks knows they can be a challenge. This was from last year BTW, anyone know different?

Skippy · October 2016

BB. said:

Summer/Winter Room temperature (and probably humidity), how often the doors are open (the teenager factor), how often do you put room temp food in from shopping, do you make a lot of ice, do you clean the condenser coils, how old the fridge is, is the insulation water logged, etc. all matter.

-Bill

I will have to agree with ya there bill.... now that I am on solar powered batteries, I am really alot more aware of the weather, and the usage of the fridge . . . if I open the door twice - the compressor comes on . . but if I leave it alone, it will go for hours - just sitting there . . . you don't really notice things like this when you have unlimited - non stop power (wall outlet) . . .

I have noticed something that I would like some help on.... the batteries . .

5 am in the morning, I wake up, and first thing is too check the system status. . ya . . . go figure . ..:)

Here are the facts :
Absorb time varies from 0 up too as high as 300 min - with no float - it does go into float, just not very often . .

Here is what the midnite meter reads - sitting solidly on 80 %

Here is what the tristar reads - notice the read and yellow l.e.d.s at the top, with a voltage of 24.6 - this is WITH the battery sense wires connected and working . . 5 am just before the sun comes up.

Problem that I am having, is that the tristar meter manual states the following for red and yellow lights :

Have not been able to even find (section 11.0) for the state of charge voltages

So, I have one meter reading 80 % DOD (midnite)
I have the tristar reading 24.6 V
But I also have the tristar telling me with the red and yellow l.e.d. that it's down to 0-35 %

I saved this picture from somewhere else, and going by the chart, the 24.6 is between 50 and 75 % . . . hmmmm

The extra long absorb charge time can be explained by this :

If the battery happens to get down low enough, it will do this :

But, I have NEVER seen this battery bank down to 23 V yet . . .

Image: https://us.v-cdn.net/6024911/uploads/editor/eh/u8i2e2kuk36x.jpg

So guys . . . anything I should do differently ? or is it running fine . . just worrying too much ?

mcgivor · October 2016

Nothing wrong there, Tristar state of charge led's indicate state of charge whilst charging, so yes just worrying too much, I thought the same till reading the manual more carefully.

mcgivor · October 2016

One more thing, to check true state of charge disconnect any loads, including the inverter and wait a while, the voltage will creep back up. Recommendation is 2 hours but not practical.

Skippy · November 2016

Now that we are into November and December time of year, I am getting alot of cloudy days . . .
So far, I can run the fridge 24-7 . . . except for the times when I get three days of cloud in a row. . . About 1 a week or so . .. Then I unplug the fridge for a couple of days (60 % on the meter) and once it gets into float stage, I plug back in and use it until the next cloudy period.

So far so good.

Good news is, My 2 KW array has produced 2.4 MWh from November 1 to November 1.

Skippy · March 2017

Well guys, here is an update for ya . . .

I unplugged the fridge around the end of November - since it has been grey and cloudy since then . . let the batteries get into "float" charge, then disconnected everything and let it sit . . .

Not sure if that was a good idea or not, but I did not want to have the solar panels overcharging the batteries, when I was not using them for anything . . .

Just last week, we are starting to get more and more sun - I can tell, because the solar water heater is coming on more and more

So, I turned on the inverter, and plugged in the fridge - last Saturday . . . for one day, I had too unplug the fridge and let the batteries come up (wed-thur) - more clouds . . .

Just today however, I was able too do 2 full loads of laundry - with the fridge plugged in all the while . .
At the start of the washing, the CC had a reading of this :

Image: https://us.v-cdn.net/6024911/uploads/editor/yz/y354p4rg1lh7.jpg

All the while - I was doing laundry, the voltage kept going up, until the end of the last load of laundry . . .
As soon as the washer shut off, about one second later, the meter went right into absorb . . and the voltage and amps dropped accordingly . .

Image: https://us.v-cdn.net/6024911/uploads/editor/up/huekvyjbdl3j.jpg

I said before that I am probably over paneled on this system - just too run my fridge . . .. but it is REALLY NICE to be able too do multiple loads of laundry - off grid - on a sunny day . ..

I'm happy with it .

mike95490 · March 2017

I don't see that the voltage went down. It actually went up as it transitioned to Absorb: 29.5V If it dips too low, it falls out of absorb and goes back to Bulk MPPT

Virtuousdesires · March 2017

Amazon has a pure sine inverter by Aims @1200 watts continuous for $139.00. It seemed to run my fridge just fine. It wouldn't run my washer in high speed spin cycle though. I know you get what you pay for, but I bought it to get me by till I can get a Magnum inverter. It's a hard wire only model aimed more at the RV market. Though I haven't used it much it seems fine. My fridge is a Frigidaire 18 Cubic foot. The start up is something like 300 watts and running about 100 watts. I still don't know how much the defrost cycle eats up though. 210 amp hours seemed to power it 15 hours just fine using 30 percent of my battery capacity. But I think I don't have enough panel to charge the batteries because they didn't charge all the way on 200 watts worth of solar and that was all day charging with no load and plenty of sun.

Just thought I would share that in hopes it would help.

Skippy · May 2018

mike95490 said:

I don't see that the voltage went down. It actually went up as it transitioned to Absorb: 29.5V If it dips too low, it falls out of absorb and goes back to Bulk MPPT

Been a while since I have been on, so sorry for the delay.

But you are right. The Amperage and Wattage dropped accordingly.

Typo !

Solar to run a fridge.

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