Apartment fridge install

[Sabatical]

Tell me if this seems reasonable. The capacity of the solar panel to produce and the amount of energy allowed into the batteries are two different things. My take on it is that usage created a 54ah hole in the battery bank capacity that the solar filled.

It is quite possible that i am oversimplifying to meet my apprentice level of undersanding.

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[Sabatical]

that is under ideal conditions. so unless you are tracking the sun you would only multiply the 13a by 4-5 hours depending on several factors. highdesertranger

We are definately not set up ideal. Flat mounted panel cleaned once every other week and out of direct sun after 3pm or so.

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[Sabatical]

This is my panel. Sorry for crappy picture.

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[jonsun]

When the battery starts to get full the charge controller limits the voltage, amps taper.  The rest of the energy is not harvested, not measured, shut off, those amps never flow.

How much you get today depends on what you used last night.

oh yeah, derr. I guess I assumed it was overall produced instead of sent to battery. The batteries are filling up by eve though, right?

so great this actually gives a good indicator of fridge and inverter usage.

 

[highdesertranger]

you are correct as far as, if you use X amount of energy you controller is only going to replace X plus a little more counting for loses. highdesertranger

 

[jonsun]

that is under ideal conditions.  so unless you are tracking the sun you would only multiply the 13a by 4-5 hours depending on several factors.  highdesertranger

years ago when I was first researching panels there was a calculator site that I looked at. Its summation doing the math of the suns arc relative to latitude was around the summer solstice between 35n-45n with flat panels a calculation of 8.8hrs was ideal.

 

[tx2sturgis]

And!!!....the learning continues....I am SO glad this thread was given a second 'lease' on life.

Earlier in the thread I mentioned that DC-AC inverters are really noisy during operation, when it comes to RF, they pretty much pollute the RF spectrum in the 'near field', with a broadband RF 'hash' or 'buzz', especially in the lower end, the HF frequencies, but also all the way up into the VHF and UHF range.

Then I got curious about Sab's curvy little Morningstar inverter...and looked it up.

Here is a passage from the description:

"The Morningstar SureSine SI-300-115V-UL is an ideal inverter for small off-grid systems including cabins, RVs, boats, and remote power systems for telecommunications and other off-grid applications. Morningstar equipment is especially popular in the telecommunications industry due to exceptional reliability, an efficient design, and low radio frequency interference."

WhooHooo!

This means that the Morningstar SureSine inverter might be on the short list for my future setup!

SCORE!

There are few manufacturers paying much attention to this stuff...I'm glad MorningStar is...I have several smaller MorningStar solar controllers...they do seem to make good, quiet, reliable units.

Anyway, sidebar over, class resumed!

An apple for the teacher, Mr Sabatical....

 

[jonsun]

Oh yes Sabatical we have to factor in the hours when the panel is actually running the fridge by itself and charging the battery. So we should be looking more around double those figures I think. We'll see soon enough with the killowatt though.

 

[jonsun]

And!!!....the learning continues....I am SO glad this thread was given a second 'lease' on life.

Earlier in the thread I mentioned that DC-AC inverters are really noisy during operation, when it comes to RF, they pretty much pollute the RF spectrum in the 'near field', especially the lower end, and the HF frequencies, but also all the way up into the VHF and UHF range.

Then I got curious about Sab's curvy little Morningstar inverter...and looked it up.

Here is a passage from the description:

"The Morningstar SureSine SI-300-115V-UL is an ideal inverter for small off-grid systems including cabins, RVs, boats, and remote power systems for telecommunications and other off-grid applications. Morningstar equipment is especially popular in the telecommunications industry due to exceptional reliability, an efficient design, and low radio frequency interference."

WhooHooo!

This means that the Morningstar SureSine inverter might be on the short list for my future setup!

SCORE!

There are few manufacturers paying much attention to this stuff...I'm glad MorningStar is...I have several smaller MorningStar solar controllers...they do seem to make good, reliable units.

Anyway, sidebar over, class resumed!

An apple for the teacher, Mr Sab...

Could try putting the inverter in a steel box.

 

[tx2sturgis]

Could try putting the inverter in a steel box.

It's not the case of the inverter that radiates the noise, its all of the interconnecting cables that propagate the noise. In fact most of the inverters have a metal case already. And of course, inverters need air flow.

On the system in my cargo trailer, I have installed several 'snap-chokes' and a few toroids. It helps.

 

[John61CT]

Low RFI is a niche requirement, marine-class vendors a good place to start, look for FCC "type B" rating at least, type A even better.

Samlex PST is apparently OK.

Ham radio forums are the place to google, search the eHam threads for lots of discussions.

 

[tx2sturgis]

Low RFI is a niche requirement, marine-class vendors a good place to start, look for FCC "type B" rating at least, type A even better.

Ham radio forums are the place to google, search the eHam threads for lots of discussions.

I know about Type A and Type B. And Part 15.

Most of this stuff is Type B, either by labeling or by default. If you see one that is FCC rated or certified Type A let me know. RFI filtering adds cost and complexity, and solar controllers and inverters are now a consumer commodity, and every dollar added to the price means a drop in sales. They are mostly sold for the mass market. "Filtering? we don't need no stinkin filtering!"

And most ham radio forums are boring as hell....have you ever surfed into one from a random search?

Snooze-ville. 

BTW I have posted several reviews on eham. Yep....been there....done that...got the t-shirt.

 

[John61CT]

Also Projecta is very well shielded, but being Aussie probably don't do 110V.

 

[Sabatical]

Educating myself on how to turn the kill a watt numbers into something i can understand. The link is part of what i found and explained in easy to understand terms, which is what i needed.

http://forum.solar-electric.com/discussion/10596/formula-for-battery-amp-hours-watts-used-etc

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[tx2sturgis]

I found this little bit of interesting information:

Sab, the inverter you are using has a low-power stand-by function operated by the #1 dip switch.

Which mode are you using for these tests?

Apparently the 8 watts you have been assuming is standby wattage, is actually a 'trigger' that turns the unit on. With an AC load under 8 watts, it goes into standby and consumes a lot less (one tenth of 450 ma, am I reading that correctly?) So 45 ma?





The kill-a-watt plugged into the inverter may be keeping the inverter from going into standby even when the fridge compressor cycles off!

Lets assume the inverter can go into standby when not needed...this is gonna knock the standby power consumption down a fair bit...or so it would appear.

I'm sure liking this little inverter!

 

[tx2sturgis]

WOW!

More info! 

55 milliamps on standby!

Does NASA know about this thing?

 

[Ballenxj]

55 milliamps on standby!

Does NASA know about this thing?

Even if NASA knows about it, you can bet the Chinese will beat them to duplicating and marketing.

 

[tx2sturgis]

Even if NASA knows about it, you can bet the Chinese will beat them to duplicating and marketing.

Man....we could sure use SW's expertise in the math department right now...but I'm not sure he's talking to us anymore...



If my math is correct, the standby on the inverter would consume roughly 16 wh per day, if it was on standby for 24 hours.

Of course, the standby will be interrupted when the fridge compressor kicks on, so lets say 8wh per day.

Lets say your average 200 watt solar array can make 1000 wh per day, with 5 hours of good sun exposure.

Lets say the fridge is using 60 watts when running. At 50% duty cycle, that's 720 watt hours per day. (it might be less in the cooler evenings)

Further, the inverter is listed as 92% efficient. So, that's about 66 watts equivalent.

The inverter specs list .450 amps for 'operating' current. So that's about 67 wh a day, for 12 hours a day when the compressor is running.

Added up:

8+720+66+67=861wh per day.

Iffy, on 200 watts of panels.

300 watts of panels might make it doable with some reserve for cloudy days and lower sun angles.

Now, 861 watts divided by 12.5 battery voltage is about 69 ah drain per day, if there was zero solar charging.  Am I close on the numbers?

If the math guys get in here and have better numbers, by all means...jump in!

Sternwake, HDR, John61CT, IGBT, GotSmart, jimindenver, anybody? 

Help out please....

(crickets).....

:-/

 

[John61CT]

Actual measurements are needed IMO not worth arguing how many angels fit on a pin.

Start with a pair of GC's, be ready to add another pair if during testing there's any indication they'll be needed.

A solid shore charger, custom setpoints and absorption duration, minimum 60A, 100+ better.

A good AH-counter ideally full battery monitor, plus DMM.

Get the fridge set up as efficiently as possible, record AH/day usage in various scenarios.

Maximize panels on the roof anyway, to me a given. If not, wait for testing results to see how many to buy.

They will produce in real life on average way below the STC ratings.

 

[tx2sturgis]

Oops...caught an error in my calculations...720 should have been 792.

The total watt-hours would then be 933 wh per day.