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I guess its time for me to start my own Home shop thread.

Just out of curiosity, how big of an area does that cover?
Just to put some scale in my head.


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I am Ox and I approve this here post!
panels are 7.5x4ft. 90 of them stacked next to each other would take up ~3000 square feet.
 
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The big thing with batt insulation and pole barns is that critters love it! I don't see why rockwool would be any different. If mice can get in your walls they'll tell all their buddies and they'll fill those walls up!

Rodents won't chew Rockwool, or so they say.

I've been doing bookshelf girts and 24" rockwool batts. The bookshelf girts make it easy to build the wall plumb and straight.

20240425_102027.jpg
 
You are gonna need some honking big batteries, and you are gonna need a lot of solar panels running for days between each usage, and you will not be doing any work in your shop during the winter months. Doesn't seem like an outstanding strategy to me.

I have a very large solar array (50KW), and even in sunny california, 70% of the annual power is produced during the 3 summer months, June/July/Aug, during winter months you get maybe 5% of your annual solar production over 4-5 months.

One viable solution: buy a diesel powered generator, and view that as your primary power source, with solar just supplementing to save a little diesel here and there.
It's a matter of running the numbers and planning the system. 2 key factors: conservation and usage. The solar array will be larger than a gridtie system because the goals are different.

With gridtie the goal is usually (depending on the state) to cover one's annual usage with solar. Easy to do. Generate more than usage in the summer, use the excess credits in the winter when usage exceeds generation. Every generated watt is useful - it either goes back into the grid or is used onsite.

With off-grid the goal is to keep the power on 24/7. The ideal scenario is: sun comes up in the morning, PV panels charge the batteries to at least float stage by 10am and continue to charge the battery bank in float mode till the sun goes down. In float mode, there's lot of excess solar capacity that isn't being used. (It's possible to divert it to some other use - heat, pumping water, etc, but it's not contributing to the main loads.) The system size needs to be larger to compensate. Using the generator is usually necessary occasionally during November and December, but increasing solar capacity is usually cheaper than generator operating costs. Hard to do it all from solar - there's always a five day gloomy period every winter that requires a generator, but engine driven power is way more expensive than solar.

I'm on the grid, run a full manual machine shop with a CNC mill and lathe and average less than 300kWh/month in the summer months. That's peak usage, mostly due to dehumidifiers.

A 50kW array? Wow. What are the loads that require that much energy?
 
It's a matter of running the numbers and planning the system. 2 key factors: conservation and usage. The solar array will be larger than a gridtie system because the goals are different.

With gridtie the goal is usually (depending on the state) to cover one's annual usage with solar. Easy to do. Generate more than usage in the summer, use the excess credits in the winter when usage exceeds generation. Every generated watt is useful - it either goes back into the grid or is used onsite.

With off-grid the goal is to keep the power on 24/7. The ideal scenario is: sun comes up in the morning, PV panels charge the batteries to at least float stage by 10am and continue to charge the battery bank in float mode till the sun goes down. In float mode, there's lot of excess solar capacity that isn't being used. (It's possible to divert it to some other use - heat, pumping water, etc, but it's not contributing to the main loads.) The system size needs to be larger to compensate. Using the generator is usually necessary occasionally during November and December, but increasing solar capacity is usually cheaper than generator operating costs. Hard to do it all from solar - there's always a five day gloomy period every winter that requires a generator, but engine driven power is way more expensive than solar.

I'm on the grid, run a full manual machine shop with a CNC mill and lathe and average less than 300kWh/month in the summer months. That's peak usage, mostly due to dehumidifiers.

A 50kW array? Wow. What are the loads that require that much energy?
thats kinda what i'm thinking...

so lets say the machine i'm planning on using has a 20KVA spindle, the actual load wont always be 20KVA but lets assume the worst.
1714061596101.png

so if i ran this machine 8 hours a day full blast, it would take 6 8 hour days of all out run time to drain my 800kwh battery bank. this is of course assuming there's ZERO power coming in from solar, which is the worst case scenario. so this setup would get me through a week of essentially complete darkness as the worst case, in reality the machine would only see full load for about 20-30% of the time.

unless my train of thought here is completely wrong, i SHOULD be ok, but in the worst case i can always add a generator down the line. of course there will be other loads on the system besides the machine itself, but still, i dont think i'm completely off base here, am i?
 
No shop thread yet, too embarrassing. Picture your building with a few machines, random lighting and virtually zero consideration for permanent, organized storage. Everything in here was given just enough thought to do the job at hand. Most of the lights are plugged in with extension cords strung through the trusses, air is supplied by hoses run across the floor.

I didn't finish the building before I started building a shop - the money wasn't there at the time. Now I'm hustling to finish jobs while trying to sort out the building, it's a mess. I have half of one short wall and half of the adjacent long wall insulated. I have to move 15k pounds of stuff before I can go further.

I will probably start a shop thread once I get things sorted out a bit better. You are definitely going in the right direction by focusing on infrastructure first.


If you google "Rodents nest Rockwool" there's substantial evidence to the contrary.

Rodents can't chew through metal or concrete. They get into anything else.

I stand corrected. Damn internet lore 😅
 
No shop thread yet, too embarrassing. Picture your building with a few machines, random lighting and virtually zero consideration for permanent, organized storage. Everything in here was given just enough thought to do the job at hand. Most of the lights are plugged in with extension cords strung through the trusses, air is supplied by hoses run across the floor.

I didn't finish the building before I started building a shop - the money wasn't there at the time. Now I'm hustling to finish jobs while trying to sort out the building, it's a mess. I have half of one short wall and half of the adjacent long wall insulated. I have to move 15k pounds of stuff before I can go further.

I will probably start a shop thread once I get things sorted out a bit better. You are definitely going in the right direction by focusing on infrastructure first.




I stand corrected. Damn internet lore 😅
i know how that goes! looking forward to seeing your thread when you do start it. no need to be embarrassed at all.
 
I'm with you on your plan and your vision of how much energy it takes to run a CNC spindle. The math you've done looks good to me!

Good start to focus on the big loads, that'll get you an idea of the biggest loads required, determining inverter capacity etc. It's the small loads, the ones used the most, that take the most energy. Parasitic loads, like inverter idling current, wall warts, etc are brutal. And the rule of thumb is refrigeration and water pumping take up 60-75% of the average offgrid energy budget. Clearly, your shop usage will reduce those percentages, but they'll still take a significant amount of energy.

Not a bad idea to start thinking about a generator now. Dunno how much energy they'll need to contribute, but in the smaller units, inverter generators are the most popular. True sine wave, so the charger likes it better, and the best part is they'll run only fast enough to handle the load, so a lot of fuel is saved. Some are also stackable for 3phase, though that may not be needed.
so lets say the machine i'm planning on using has a 20KVA spindle, the actual load wont always be 20KVA but lets assume the worst.
View attachment 437335

so if i ran this machine 8 hours a day full blast, it would take 6 8 hour days of all out run time to drain my 800kwh battery bank. this is of course assuming there's ZERO power coming in from solar, which is the worst case scenario. so this setup would get me through a week of essentially complete darkness as the worst case, in reality the machine would only see full load for about 20-30% of the time.

unless my train of thought here is completely wrong, i SHOULD be ok, but in the worst case i can always add a generator down the line. of course there will be other loads on the system besides the machine itself, but still, i dont think i'm completely off base here, am i?
 
I don't git the talk about a gen/set?
How on Earth did that git into the eqazsion?

Originally Em said that he was expecting to add a batt charger as needed.
I see no reason that a charger hooked up to the grid is anything to be shunned?

He ends up with a small steady load as needed, and the sun does what it can.
Not seein' the issue here?

ANYTHING is cheaper than a gen/set!
ANYTHING!

A feller that I know actually unhooked his 3ph from the grid somewhere back around 1990, when the Demand charge was killing him, and Edison was likely charging him $.14/kwh as well. He bought a pr of big gen sets (1 Cummins and 1 Detroit - only needed one at a time) and bought bulk red fuel for $.50/gal.

The Gen/sets needed rebuilt regularly, and I doubt that he saved 2 nickles over the years. But he prolly felt accomplished by unhooking from Edison (and I git that..) although he did still have a 240 1/phase line still hooked up.

Today, I doubt that you're paying any more than the $.14, and you shouldn't have any demand fee, and fuel is a WHOLE LOT more than $.50, even in 10,000 gal lots!


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I am Ox and I approve this here post!
 
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I think this is the place to share how much of a shitpile our shops are- What we do with what we have to work with. Just take care to leave out the markets you serve and specifics of what your products are or who your customers are. You might not want them to see the squalor their parts get made in lol.

But for the folks that get shit done with what we got it's probably far from ideal and this is the place to show it where people that do the same will appreciate it.

My shop's not so bad now, but I still have a temporary 14ft tall x 20ft wide main door made from junky used tin and there's a spot that's still gravel floors and water flows up when it rains heavy. I still have some romex and extension cords strung through the trusses and airhoses across the floor. It is what it is.
 
I'm with you on your plan and your vision of how much energy it takes to run a CNC spindle. The math you've done looks good to me!

Good start to focus on the big loads, that'll get you an idea of the biggest loads required, determining inverter capacity etc. It's the small loads, the ones used the most, that take the most energy. Parasitic loads, like inverter idling current, wall warts, etc are brutal. And the rule of thumb is refrigeration and water pumping take up 60-75% of the average offgrid energy budget. Clearly, your shop usage will reduce those percentages, but they'll still take a significant amount of energy.

Not a bad idea to start thinking about a generator now. Dunno how much energy they'll need to contribute, but in the smaller units, inverter generators are the most popular. True sine wave, so the charger likes it better, and the best part is they'll run only fast enough to handle the load, so a lot of fuel is saved. Some are also stackable for 3phase, though that may not be needed.
noted, i truly appreciate the input!

currently my plan is to build this and slowly start operating it while i still have a full time job. that being the case, it'll give me an opportunity to see how my energy usage is during cold/dark days while i dont HAVE to have everything running. once i get that data, i can make the corresponding decision on if i need to get a generator or some other solution.
 
I don't git the talk about a gen/set?
How on Earth did that git into the eqazsion?

Originally Em said that he was expecting to add a batt charger as needed.
I see no reason that a charger hooked up to the grid is anything to be shunned?

He ends up with a small steady load as needed, and the sun does what it can.
Not seein' the issue here?

ANYTHING is cheaper than a gen/set!
ANYTHING!

A feller that I know actually unhooked his 3ph from the grid somewhere back around 1990, when the Demand charge was killing him, and Edison was likely charging him $.14/kwh as well. He bought a pr of big gen sets (1 Cummins and 1 Detroit - only needed one at a time) and bought bulk red fuel for $.50/gal.

The Gen/sets needed rebuilt regularly, and I doubt that he saved 2 nickles over the years. But he prolly felt accomplished by unhooking from Edison (and I git that..) although he did still have a 240 1/phase line still hooked up.

Today, I doubt that you're paying any more than the $.14, and you shouldn't have any demand fee, and fuel is a WHOLE LOT more than $.50, even in 10,000 gal lots!


--------------------

I am Ox and I approve this here post!
average of 20 cents per kwh for last month...
 
thats kinda what i'm thinking...

so lets say the machine i'm planning on using has a 20KVA spindle, the actual load wont always be 20KVA but lets assume the worst.
View attachment 437335

so if i ran this machine 8 hours a day full blast, it would take 6 8 hour days of all out run time to drain my 800kwh battery bank. this is of course assuming there's ZERO power coming in from solar, which is the worst case scenario. so this setup would get me through a week of essentially complete darkness as the worst case, in reality the machine would only see full load for about 20-30% of the time.

unless my train of thought here is completely wrong, i SHOULD be ok, but in the worst case i can always add a generator down the line. of course there will be other loads on the system besides the machine itself, but still, i dont think i'm completely off base here, am i?
My Speedio is rated 9.5 KVA, but I normally only see about 9 amps load most of the time it's cutting parts. At 195v that's 1,580W if I guess a .9PF.
Your biggest draw will probably be your air compressor by far, and HVAC if you'll be using it.
 
My Speedio is rated 9.5 KVA, but I normally only see about 9 amps load most of the time it's cutting parts. At 195v that's 1,580W if I guess a .9PF.
Your biggest draw will probably be your air compressor by far, and HVAC if you'll be using it.
ya so my battery bank could run that thing for over a month... lol
 
More the question is - how long would it take you to charge them up?

That post above about 70% of total charge comes in 3 summer months was an :eek: for me!
I wouldn't'a guessed it being THAT drastic!


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Think Snow Eh!
Ox
 








 
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