First attempt with solar, need advice.

VR Nicastro

New Member
Joined
Jun 19, 2021
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7
I’ve always been intrigued by solar power and I now have an application I can use it for. I understand the components needed but having issues with sizing of the components.
I have an internet hosting site and beam the internet to my business using 5ghz radios. I would love for my first try with solar to be powering my hosting site.
I rent the location where my hosting site is because high speed internet isn’t available on the street my business is on.
I have calculated the total wattage to be a little less then 55 watts of all the equipment I use. I’m trying to figure out how to size the system I need. The system would be running 24 hours a day.
I would like for it to be able to run for 48-72 hours without needing a charge.
There is electric at my hosting site but I wanna give this a try.
I am located outside Philadelphia Pa.
How many panels would I need, recommended wattage?
How many batteries and what size would they need to be?
Proper size inverter? Charge controller?
Is there a network enabled system to view the solar system info off site? I know there are Bluetooth versions.
Looking forward to seeing what you all have to say.
Thank you
VR
 

HRTKD

Boondocker
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Apr 24, 2020
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Somewhere South of Denver
The system audit found in the Resources section of the forum is a good place to start. You figured out the wattage, just plug that into the spreadsheet and see what comes out.

 

snoobler

Solar Honey Badger
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Jul 10, 2020
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HBR, AZ
Welcome to the forum.

55W * 24h * 3 days = 3960Wh

You'd need a battery with that much usable capacity.

Your available solar:

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Sizing for December:

55W * 24h / 2.77h = 476W

You'd want 50-100% more than that to ensure you could "catch up" recharging the batteries on good days when you don't collect enough on bad.
 

VR Nicastro

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Jun 19, 2021
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I’ve watched a few videos on this and done some research. Batteries are the most expensive part to this whole equation.
I have been a carpenter for almost 40 years. I considered getting into this field probably 20+ years ago. It was even more expensive back then and battery technology wasn’t as good.
Back then hydro power was the easiest and most effective way to produce power but you needed running water on your property. Right now I am basically doing this as an experiment because I do have electric at the site. Maybe I should lower my expectations of how long I want the system to run without needing to be recharged. Just to get my feet wet and learn how to do it.
 

12VoltInstalls

Photon Sorcerer
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Nobody likes lead acid batteries anymore.

While the up-front is pretty low cost, you need to vent them properly. If you don’t drain them too low overnight they can last well. Then do LFP later.
I guessing you would want like 400Ah of batteries. Maybe 400W minimum of panel to exceed the need? At 55W that’s optimistically “one battery” (FLA) so double that, multiply by three is six walmartha Maxx batteries: $420
Lifepo will be a lot more moula.

Whst I wrote is just rough guessing off the top of my head for discussion’s sake. Do the math and it will reveal itself. Not trying to discount anything said above.

So batteries $500, true sine inverter $200, charge controller/panel kit 200W ~$250, two more panels $180-ish, mppt charge controller (since you won’t use the kit pwm) $240, mounting stuff $100, 8ga panel cables and other doodads $50-$100. Decent inverter-to-battery cables $70

$1600 and it won’t save you any money.
 

VR Nicastro

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Jun 19, 2021
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7
Battery options. I’ve seen many different options for batteries.
People using old 12v medical equipment batteries.
Tesla battery packs.
Forklift batteries (HEAVY!)
What about Prius battery packs?
I’ve also seen people making their own using 3.6V cells. To me this is a lot of work for not much in savings. I always figure my time in any project I undertake.
 

VR Nicastro

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Jun 19, 2021
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What about a hybrid system? Wind/solar. In my area there’s always a breeze. Lots of open farm land. I know the typical blade style turbines need around 5MPH to start up. The vertical style need around 3MPH. Anyone using a hybrid system?
 

snoobler

Solar Honey Badger
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Jul 10, 2020
Messages
8,430
Location
HBR, AZ
Battery options. I’ve seen many different options for batteries.
People using old 12v medical equipment batteries.
Tesla battery packs.
Forklift batteries (HEAVY!)
What about Prius battery packs?
I’ve also seen people making their own using 3.6V cells. To me this is a lot of work for not much in savings. I always figure my time in any project I undertake.

Any of the above are viable except for Prius batteries. Anything besides lead-acid batteries will require you to develop significant expertise with them.

What about a hybrid system? Wind/solar. In my area there’s always a breeze. Lots of open farm land. I know the typical blade style turbines need around 5MPH to start up. The vertical style need around 3MPH. Anyone using a hybrid system?

You won't get any meaningful wind below 10-12mph with a 6' diameter wind turbine.

Vertical wind turbines are generally garbage and produce less power than vertical.

Educate yourself on wind:

 

12VoltInstalls

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people making their own using 3.6V cells. To me this is a lot of work for not much in savings. I always figure my time in any project I undertake.

that’s a peculiar comment

what is your time worth?! the diy lithium battery packs cost what? 25% of the factory assembled units? I gather that savings can be like ~$800 and take 5 hours of time. or $160/hour
 

VR Nicastro

New Member
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Jun 19, 2021
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that’s a peculiar comment

what is your time worth?! the diy lithium battery packs cost what? 25% of the factory assembled units? I gather that savings can be like ~$800 and take 5 hours of time. or $160/hour
I’m one of those people that I feel my time is worth something.
For argument sake, If I’m at a store and I want a product that costs $10. I know another a store 2 miles away has it for $8. I’ll buy it for the $10.
Between gas and my time it’s not worth it for $2.
In my profession I average $100+ an hour. Don’t get me wrong, if I’m going to save hundreds of dollars on something that’s ready made I’ll take the drive but I wouldn’t waste days on building something. I’ll build things I can’t buy.
On pre made items that have a warranty I feel it’s worth it. That battery that I’ve saved (your number) 25% on, if a component fails and becomes useless in a year did I really save anything? Now I need to take it apart, figure out the issue or just call the manufacturer for a replacement.
 

VR Nicastro

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Jun 19, 2021
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I think it would be easier to convert many things in my home to 12v. The entire lighting circuit for one in the home. You can’t convert everything in a home to 12v but there is savings to be had in doing so. If I were to build a new home I would certainly consider powering it with solar planing accordingly.
 

12VoltInstalls

Photon Sorcerer
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-I’ve always been intrigued by solar power and I now have an application I can use it for.
-Right now I am basically doing this as an experiment because I do have electric at the site. Maybe I should lower my expectations of how long I want the system to run without needing to be recharged.
-Just to get my feet wet and learn how to do it.
There is electric at my hosting site but I wanna give this a try.
Well with the stated goals and conveyed concerns for batteries/cost for this ‘experiment’ your feet would be fairly wet learning how to assemble a battery.

I completely understand the cost accounting of time/value but in some cases- like this- the investment of R&D is usually factored for the increased benefit of production over time.
Like for your carpentry business: the cost of merely showing up to a job with tools/crew is probably what? $250-$350? For a four hour job that’s $75/hr cost, but for a three week remodel the cost to the consumer nearly disappears because mere travel to work is neither deductible nor is something most contractors charge for.
Once you balance, build, and implement your first battery bank that cost ‘goes away’ with both efficiencies and amortization over twenty years.
Conversely, if you wind up installing stuff for people, the battery becomes a marked-up commodity if you buy them instead of building; whereas if you build them, you have a raw cost and a small overhead factor as expenses, and a labor income you can leverage using an employee whose income expectations are less than yours.

YMMV
I think the suggestions (mine included) are quality parameters infused with getting the most for the dollars invested.

it’s just confusing to me because replacing grid with solar basically never saves money. Solar essentially only makes sense if:
one is willing to spend money on principle (regardless of the fallacies in that mindset); it is a fun hobby that cost or ROI isn’t the point; one is willing to invest for backup power should the grid be down; if it enables circumstances that provide an immediate cost offset justification; or there is no grid available.

$100/hr ~= $200K/yr. Pretty good income for a carpenter unless you’re in certain metros like Washington DC / Arlington VA then that’s way too low on one hand, and on the other hand your cost of living expenses have you busting it to maintain a $50K standard of living.

My gut tells me 55W is low. It feels too tight for any headroom/margin of error.
In your case if I were to build for that a) I’d have 150% of the watt hours needed to run 14 hours/day times 2 for useable battery Ah or Wh- minimum. Have enough panel to supply 150% of the 24-hour load in 8 hours. That might be the bare minimum for cloudy days that might work. And design the system to allow for both additional battery (-ies) and panels should the need or desire arise.
 

VR Nicastro

New Member
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Jun 19, 2021
Messages
7
As I said, I’ve always been interested in alternate forms of producing power.
It still seems the cost hasn’t come down enough in 20 years to make it a viable option vs grid power.
If you have the option for hydro power that would be the most cost effective way as it was 20 years ago.
Constantly changing the batteries. No need for a huge battery bank.
I guess I’ll wait another 20 years.. lol
 
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