Author Topic: Dumb question  (Read 1198 times)

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Astro

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Dumb question
« on: October 18, 2021, 08:34:10 PM »
What kind of balance do you guys have as far as watts in to inverter size??
I mean I know you can have 1000 ah pack and a couple 6,000 watt inverters running off it, but at some point it is going to go dead if you are not putting enough back in to it. I am collecting parts for a smaller version of my mill design and I am wondering how many watts I need to make to accomplish a couple things.
I want to run my fridge and freezer full time off inverters and while I can figure out how many AH I will need for x amount of time, I am wondering how many watts I am going to need to be able to keep up. I also understand wind conditions dictate. I guess what I am asking is is anyone doing this or a similar load, full time, with a 500w mill? !000 watt mill? 1500w mill? I figure to the high side in these things and not including inrush, say I am using 1500 watts when both fridge and freezer are running. But I have no idea how often they run. Again, I understand it matters how much the door is opened, ect. We get into them pretty often. Freezer is new so pretty efficient but fridge is older.
I thought I would ask for some real world experience about what is working for you guys.
 I have some more dumb questions, but we will start there.


Astro

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Re: Dumb question
« Reply #1 on: October 18, 2021, 09:36:16 PM »
Well I think I figured it out. Google says the avg fridge runs 8hrs a day. it takes about 600 watts. Not counting start up. So if I have a freezer also, figure 1200 watts (in the previous post I rounded up to 1500 watts). 1200 watts for 9 hrs (again I figure high in these things) 10,800 watts a day. Say 11,000.
SO a 500 watt mill would need to produce for 22hrs a day.
A 1000 watt mill for 11 (obviously)
and a 1500 watt mill for about 7.5 hrs a day.
Does that sound about right to everyone??
SO if I am building a small mill and wind it with 14 awg wire, can I push it to 30 amps? 25 is probably safer huh? At 24v that is 600 watt max, correct?
It would seem if these numbers are correct, to run a 5 amp fridge for 8-9 hrs a day, one would need a 5-700 watt mill at a minimum. Plus enough AH storage in case you do not get wind for a day. A 500 watt mill would need to charge for 9.6 hours a day to keep up with a 5 amp fridge running 8 hrs a day.
Does this sound about right??

Astro

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Re: Dumb question
« Reply #2 on: October 18, 2021, 10:01:19 PM »
Ok, it has been a long day. LOL Watts out equals Watts in. LOL hello Einstein.

So what equipment is available for me to utilize a small system to it's maximum? Say I am making 500 watts and gradually, maybe in a day, maybe in 3 days, my pack gets down to 80% and shuts off. If I put in a automatic transfer switch it will switch back over to grid power. But I do not want it to go back on off grid power until the battery bank is fully charged again. That may take a day it may take 2 or 3.
I am thinking that a regulated output of 12,24 or whatever volts on the charge controller when it goes into dump load would be nice (because the pack is now fully charged) then I could fire a relay and trip the automatic transfer switch back to off grid power until it runs down to 80% again. Or just a set of contacts to wire into  on charge controller that are tripped when it goes into dump load, would work as well.
SO what I am asking is, how am I going to keep the transfer switch from switching back to off grid until the batteries are fully charged?
Does someone make something like that or am I stuck trying to figure it out with a transfer switch and how to trip it back to off grid once the batteries are fully charged?? Maybe a voltage or current sensing relay on the output of the controller to the battery bank or dump load output??? I do plan on making another mill in the future obviously if I want to get both the fridge and freezer off grid, but I would like to get every ounce out of the one I am building now.
 Sorry for the dumb questions, I have no idea what is available on the market for off grid controls. Totally new to it all and am dumb to what is available. If they do not make it, they should and if not I kind of already gave the answer, of how to do it, by you guys letting me ramble on and on and talk it through.

Good news is my wife has been not interested in this idea at all. She does not understand it and just lets me ramble. But running the numbers in this post, I told her that if I can get just the fridge off grid, we will save what our highest bill in the summer is (about 1700 KWH) by not running the fridge on the grid all year. Suddenly she is like "REALLY??"

Whoops. EDIT. If the Xantrex c40 can take 50v I could be pushing 1,000 to 1250 watts. on 14 awg coils correct?
So I might want to go with a c60 instead of a c40. Correct? IDK what kind of voltage I am going to be making, but it seems like a good idea to just go with the c60.
« Last Edit: October 19, 2021, 12:43:39 AM by Astro »

Simen

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Re: Dumb question
« Reply #3 on: October 19, 2021, 01:18:27 AM »
Well I think I figured it out. Google says the avg fridge runs 8hrs a day. it takes about 600 watts. Not counting start up. So if I have a freezer also, figure 1200 watts (in the previous post I rounded up to 1500 watts). 1200 watts for 9 hrs (again I figure high in these things) 10,800 watts a day. Say 11,000.

I think you misunderstood google a bit. ;) Those 600 Watts would be for the whole day; not for one hour... :) (A good fridge today use around 400-500 Wh a day.)

That would make it easier for you to get them off grid, but your wife less happy prebaps? :D
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SparWeb

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Re: Dumb question
« Reply #4 on: October 19, 2021, 01:45:26 AM »
Yes, I was going to just check on the difference between "Watts" and "Watt-hours", just to make sure.
One is a rate, the other's a quantity.  They get mixed up so often, usually in the context you can just "get it" and read on.  But when trying to figure it out with number, you have to use the right units or it won't add up.

The only stupid question is the one not asked.

The answers to your other questions are going to come, with time and research.  No easy answers from us folks in the internet (I don't live in your house).  I'd suggest being methodical.  Get a plug-in power/energy meter.  They're cheap and easy to use.  Leave your fridge plugged in to one for a day and tomorrow you'll know both: what the peak power was and how much energy it used in the past day.  Do the same for everything else in your house and then you'll know something solid that you can use.

Or just read your electricity bill.

Sounds "stupid" but I'm serious.  I did the same thing myself.  Made a lot of measurements until I was able to square what I was paying for with what I thought I was actually using.  In the end it added up, and all the details opened my eyes about how much I used to do what, and what I needed to improve.
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bigrockcandymountain

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Re: Dumb question
« Reply #5 on: October 19, 2021, 08:28:34 AM »
I will add that i like to use energy star labels. They will have kwh/ year rating. (kilowatt hours per year)

Say your fridge uses 365kwh per year(mine is very close) 

That's 1kwh per day.  365÷365

1kwh is 1000wh

1000÷24 = 42 watts continuous. 

A big fancy fridge might be 700kwh/year or more.
1.92kwh/day
80 watts continuous

Astro

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Re: Dumb question
« Reply #6 on: October 19, 2021, 09:18:05 AM »
I will add that i like to use energy star labels. They will have kwh/ year rating. (kilowatt hours per year)

Say your fridge uses 365kwh per year(mine is very close) 

That's 1kwh per day.  365÷365

1kwh is 1000wh

1000÷24 = 42 watts continuous. 

A big fancy fridge might be 700kwh/year or more.
1.92kwh/day
80 watts continuous

Yeah the freezer is a year old and I am sure we have the paper work around here, The fridge??? IDK I bought it used before we got married. I would guess it is 20-25 years old. Jesus 20 years old sounds old but that was only around the year 2000. I suppose I will buy a meter, because you are right, nothing beats knowing like,.... knowing.

As for Google, I didn't actually read it. I just read the couple of lines that came up when I typed the question in. It wasn't the only thing I was confused on last night. I was worn out and fell asleep sitting up in the recliner. LOL. Cat woke me up at 1:30 am and I finally went to bed and got some good sleep.
Getting old sucks. I do not know how all the old people I have ever known in my life did it. Do not let anyone lie to you, it sucks. I am still to young to get away with stuff and have people say "oh he is just old". I do not get cheap meals. Yet the old body has taken a beating, or 50. Told my wife if I could change one thing from my past, it would be that I knew how every one of those injuries were going to feel later on in life, so I wasn't so stupid.
Oh well.
Tanks for the ideas. I have been writing down a material list and vendors of the items. I think a current relay on the dump load side of the charge controller is what is needed to not kick the transfer switch back to off grid until the batteries are fully charged.
As for my "figuring" I thought something was not adding up. But I was tired and jut kept spinning out. Good news is, I figured out my mill should produce more then what I posted above and the more good news is ya'll just said that my fridge and freezer do not draw what I posted above (I thought that sounded like a butt load).
Thanks guys.

Bruce S

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Re: Dumb question
« Reply #7 on: October 19, 2021, 01:10:55 PM »
I like to be sure what my electrical appliances are actually drawing.
I purchased a Watt's up meter to get the actual readings.

They're not that expensive ~~ 30/USD last time I brought one.

Cheers
Bruce 
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DamonHD

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Re: Dumb question
« Reply #8 on: October 19, 2021, 04:25:01 PM »
Two quick notes:

1) A 20 year old freezer is likely to be a terrible energy hog and indeed may be on the the biggest loads, but measure it to be sure, and you might have to consider taking it out the back...

2) Fridges and freezers have very high start-up demand compared to their running load and as others will advise who have actually done it, you'd need an inverter with a name-plate rating several times higher than the appliance for it to start happily.

(I've been buried in legal docs all day etc and may have missed something above!)

Rgds

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Astro

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Re: Dumb question
« Reply #9 on: October 19, 2021, 05:45:12 PM »
I like to be sure what my electrical appliances are actually drawing.
I purchased a Watt's up meter to get the actual readings.

They're not that expensive ~~ 30/USD last time I brought one.

Cheers
Bruce

Yeah that is what I am going to do. I could put my clamp on it, but one that just plugs in and does it's thing and then the next day I can gather the info is worth it to me. Besides always an excuse to buy new tools, right.

Astro

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Re: Dumb question
« Reply #10 on: October 19, 2021, 05:52:30 PM »
Two quick notes:

1) A 20 year old freezer is likely to be a terrible energy hog and indeed may be on the the biggest loads, but measure it to be sure, and you might have to consider taking it out the back...

2) Fridges and freezers have very high start-up demand compared to their running load and as others will advise who have actually done it, you'd need an inverter with a name-plate rating several times higher than the appliance for it to start happily.

(I've been buried in legal docs all day etc and may have missed something above!)

Rgds

Damon

Yeah I had it figured in on the inverters. As for the fridge, I like it, it runs and runs, I see new all the time on the buy and sell sites that are broken down and people are trying to sell. So I do not want a new one until I have to.
I have kind of decided that I am going to end up with more than one mill anyway and much of what I am putting together for a system will make building and adding another less expensive then the first anyway. Like wire, I am ordering extra.I ordered extra magnets. My transfer switch will have enough ampacity for rwo mills. So when I go to add one, it won't be as expensive.
Question I have is How good of mill can I build and how much can I power with 1 single mill. But We are going to find that out.

Edit. I am going to buy a new watt/amp meter you plug into the wall, but just for now and fun I put a clamp on the fridge and opened the door, I did not get the start up current as I had the meter on dc. I went and grabbed my other amprobe meter and it said it was only drawing 2 amps and yes the compressor was running.
If that turns out to be accurate, I could run both freezer and fridge off of one converter. Even if they draw 15 amps at start up, that is only 1800 watts. So say a 4 or 5000 watt inverter that is rated for 1000 watts continuous.
But I am still going to do the other plug in meter because it is a side by side and it might draw more if both fridge side and freezer side both need cooling.
« Last Edit: October 19, 2021, 07:29:24 PM by Astro »