Hello, i have been working on building a solar system to power a small shop for quite some time now but i am having some trouble calculating battery and solar array size so i decided to make an account here to ask for help.
So, what i plan to power is:

Two tall see thru fridges that each draw 4.6kwh in a day

Two bigger see thru fridges that each draw 10kwh in day

A freezer that draws 9.4kwh a day

Other that these are lights and a barcode reader machine which is about 350w per day?

I did these measurements using a tool that goes between the outlet and plug

Looking at the amount they constantly draw a 3kw inverter with 6kw surge seems to work but i cant get a good result for battery and solar array size. i also cant pick between flooded or carbon gel, both have some good upsides(cost, maintenance free)
the battery system can be both 12 or 24 volts by the way.
Thanks in advance

 

Welcome to AAC.

I am about to be... at least “non-helpful” but... I am a dad, of six, it’s too much to suppress.

A battery for the solar system would be enormous. Think of the practical problems, too! How would you wire it? How would you charge it? And when it was at end of life, disposal would be an insurmountable problem.

I say stick to a star, it’s a proven and much more practical solution.

By the way, there are solar capacity calculators online and they include the average number of sunlight hours for your location which is absolutely critical for capacity planning. Have you tried any of these?

 

This website will work it out for you.
I presume that you are not in Britain otherwise you would have written "socket" instead of "outlet" - If you were, I might be doing myself out of a job.
Go to the off-grid tab and input your battery size.
You can probably buy slightly used forklift truck batteries for a reasonable price (we normally install 40kWh). And in ten years when they are worn out, a scrap-metal merchant will pay you good money for it. About the same amount of money as it would cost you to dispose of a similarly sized lithium battery.

 

Hello, i have been working on building a solar system to power a small shop for quite some time now but i am having some trouble calculating battery and solar array size so i decided to make an account here to ask for help.
So, what i plan to power is:

Two tall see thru fridges that each draw 4.6kwh in a day

Two bigger see thru fridges that each draw 10kwh in day

A freezer that draws 9.4kwh a day

Other that these are lights and a barcode reader machine which is about 350w per day?

I did these measurements using a tool that goes between the outlet and plug

Looking at the amount they constantly draw a 3kw inverter with 6kw surge seems to work but i cant get a good result for battery and solar array size. i also cant pick between flooded or carbon gel, both have some good upsides(cost, maintenance free)
the battery system can be both 12 or 24 volts by the way.
Thanks in advance

Not practical unless you are rich and need to be very isolated to the point a utility line to the shop is impossible. As a minimum today I would use a 48V 1200Ah+ ~60kWh LiFePO4 battery bank for that usage level, then you would need at least twice your daily energy usage in solar panels to keep the system charged and have a generator or utility charger backup.

 

My solar panels out out 50KWH on a perfectly clear summer day. My average daily usage is about 35KWH. No battery backup, grid tie.

And they are providing roughly 60% of my annual usage.

So double the daily average sounds about right.

 

My solar panels out out 50KWH on a perfectly clear summer day. My average daily usage is about 35KWH. No battery backup, grid tie.

And they are providing roughly 60% of my annual usage.

So double the daily average sounds about right.

It depends a lot on your geography.
My brother-in-law lives in Denver. I ran the calculations for his address, and for a similar latitude in Europe (south of France). You would need a lot more solar panels in France than you would in Colorado, because France has rainy winters and Colorado has dry winters. You need four times as much in Britain because there is only 7 hours daylight in the winter (but the sun doesn’t set until 9:30 at the moment, but it sets so far north of west that by then, it is shining on the back of the panels). The TS hasn’t said where he lives.

 

I did think about a grid tie system but those inverterters are lacking surge power which is very needed for fridges, would it make sense if i got about 1350w worth of solar panels and used a 200ah gel battery to power them at day and switch to grid at night, that way i dont spend a ton on batterys and still have a little bit of on time when there is a blackout.
Looking online where i live gets 6.7 peak sun hours on avrage

 

I did think about a grid tie system but those inverterters are lacking surge power which is very needed for fridges, would it make sense if i got about 1350w worth of solar panels and used a 200ah gel battery to power them at day and switch to grid at night, that way i dont spend a ton on batterys and still have a little bit of on time when there is a blackout.
Looking online where i live gets 6.7 peak sun hours on avrage

You probably will spend a ton on batteries - gel batteries are good for about 300 cycles - it will be dead within the year.
A grid tie system doesn’t need surge capability, as the grid can provide that.
I have a customer in the Mull of Kintyre who shoots and butchers his own venison, and keeps it in several freezers. He has been running of nothing other than solar power all summer (Never had to start his generator)

 

You probably will spend a ton on batteries - gel batteries are good for about 300 cycles - it will be dead within the year.
A grid tie system doesn’t need surge capability, as the grid can provide that.
I have a customer in the Mull of Kintyre who shoots and butchers his own venison, and keeps it in several freezers. He has been running of nothing other than solar power all summer (Never had to start his generator)

I heard these systems cuts power if grid isnt present to prevent islanding, is that true?
Also the gel battery i was taking about is the orbus carbon gel deep cycle battery with atleast 1000 cycles.

 

Grid-tied systems have to shut down when the grid disappears, to prevent the supply conductors being live when they should be isolated. Some grid-tie inverters provide an extra output, which is maintained when the rest of the system is off and that can be used to supply important loads.

 

I have a customer in the Mull of Kintyre who shoots and butchers his own venison...

I must admit that while I am not a fan of hunting I felt a twinge of disappointment that you didn't finish this sentence "...with an directed energy weapon powered by his PV array..." or the like.

 

I must admit that while I am not a fan of hunting I felt a twinge of disappointment that you didn't finish this sentence "...with an directed energy weapon powered by his PV array..." or the like.

he’d need a long cable. . .

 

I must admit that while I am not a fan of hunting

That’s a personal preference, but I note the following:
venison is about the most environmentally friendly meat you can get, especially If you shoot it and butcher it yourself. Scotland has had no predators such as lynx and bears since about the time of the Vikings (wolves died out more recently, about 300 years ago) so easily gets overpopulated with deer.
He sent me some at Chritsmas, and I sent him some cheese from the local dairy (also environmentally friendly)
https://lincolnshirepoachercheese.com/about-us/our-ethos/

 

I did think about a grid tie system but those inverterters are lacking surge power which is very needed for fridges, would it make sense if i got about 1350w worth of solar panels and used a 200ah gel battery to power them at day and switch to grid at night, that way i dont spend a ton on batterys and still have a little bit of on time when there is a blackout.
Looking online where i live gets 6.7 peak sun hours on avrage

I'm developing a monitoring system using a solar system similar to what you propose.
This is what you get from that investment.
https://forum.allaboutcircuits.com/...rge-controller-datalogger.194146/post-1830877

 

That’s a personal preference, but I note the following:
venison is about the most environmentally friendly meat you can get, especially If you shoot it and butcher it yourself. Scotland has had no predators such as lynx and bears since about the time of the Vikings (wolves died out more recently, about 300 years ago) so easily gets overpopulated with deer.
He sent me some at Chritsmas, and I sent him some cheese from the local dairy (also environmentally friendly)
https://lincolnshirepoachercheese.com/about-us/our-ethos/

Didn't want to get off-topic. I don't eat any meat, but having several rural (US) friends who literally depend on taking their quota of deer during in the season in order to eat over the winter, I do understand that among the ways to eat animals, it's better that most.

Many more details, so terribly off-topic, must cease typi