Help me understand how Solar is cheaper at home.

boobook

Well-Known Member
Been watching this guys video's over the weekend and found them very informative.
I'm looking at setting up my shed to be off grid and trying to decide whether I go 12/24/48V.
I'd go 48V out of those 3. There is a large ecosystem around 48V batteries, inverters and solar for homes with off-grid systems using 240v
 

RBJET

Well-Known Member
I guess it makes sense in most ways. The only concern I has was wiring my own accessories off the system.
12V lighting is easy using automotive accessories but I'm unsure what happens when I go 48V. Do I use a 12V converter or do I step everything up to 240?
 

boobook

Well-Known Member
I guess it makes sense in most ways. The only concern I has was wiring my own accessories off the system.
12V lighting is easy using automotive accessories but I'm unsure what happens when I go 48V. Do I use a 12V converter or do I step everything up to 240?
Personally, I'd have the place wired by an electrician for 240V and run off grid. There are plenty of low-energy lights and fittings that are designed for indoor use with the right mounts and range

However, there are tons of 48V to 12V converters for sale. Also, I understand below 50 V is ELV so you can do it yourself. Though check that.
 

Petunia

Well-Known Member
i would use 48, step that up to 240, then step that down to 12, then step that down to usb 5 ........... reality? or bovine excrement ?
reality i just use 12 in 12 out 12 roundabout
a week of rain renders all voltages equal

Please be not offended, nor take any notice for i have been on an elctric bill withdrawal program for 12 months now, getting the shakes seriously
 

Toyasaurus

Well-Known Member
I would stick with 48/240 myself.
You would also have to start thinking about voltage drops over long distances.

I`ve done some checking on the growatt inverters, it seem`s that the one I was thinking of only does 5kw.
So you will need 2 if you have to power more than 5kw at any one time,
They are priced around $2-2.4k each.

If you take that and the BYD batteries which should be here soon at $2600 each (5.1kw)
You could get 20kw/h storage plus your inverter`s for $15.5k.
Which is less than a single Powerwall 13.5kw/h with the gateway.

I`m sure there are some other bit`s and pieces that I`ve missed but that`s about the main part of the system cost.

Even for what I spent on my powerwall`s I could nearly double the storage on what you can get now.
 

Petunia

Well-Known Member
15.5K ...... ? .... 500 billings divide 4 per year carry the one ..... 125 years on the grid, cool bananas
 

RBJET

Well-Known Member
For reference I'm running a shed, not a house, so the power draw would be minimal.
Most consumption would be low. Any high consumption would only be for short periods.
I'm thinking 200-300AH of lithium, 600-800W of solar and a 3000W inverter.
I understand how to build a 12v system but am only just learning about 48V.
 

Toyasaurus

Well-Known Member
A 48v system at 100ah is the same as 4x 12v at 100ah.
If you series 4x 12v 100ah batteries together in series you get 48v@100ah.
If you parrallel 4x 12v 100ah batteries you have 400ah @ 12v.

I think Petunia needs a new calculator or a new sense of humor.
 

Petunia

Well-Known Member
I think Petunia needs a new calculator or a new sense of humor.
I know you need enable AU spell check :cool: I have a fantastic sense of humoUr.

watts divide volts = amps ........ therein 12 vs 48 is not as simple as Ah [amp hour]

hyperthetically plucked out me ......
48v / 3000w = 62.5Amperes
12v / 3000w = 250Amperes

and i dont use a calculator:cool:
 

Toyasaurus

Well-Known Member
Touche on the humour.

What is 500 billings divide buy four supposed to mean?

Depends on how they are setup and wired.

48v/dc 100ah of storage = 5.12kwh
 

Petunia

Well-Known Member
Touche on the humour.

What is 500 billings divide buy four supposed to mean?

Depends on how they are setup and wired.

48v/dc 100ah of storage = 5.12kwh
for your 15K investment that you dont count ROI
at the current price i pay for a billing that equals 500 billings
i am billed every 3 months
500 billings divide by 4 billings per year gives 125 years with NO. I
would you like a calculator?

48v dc @ 3000 Watts = 62.5 Amps ..... 100Ah will last 1.6 hours
12v dc @ 3000 Watts = 250 Amps ........ 400Ah will last 1.6 hours

therefor 5.12Kwh means Jacques Cousteau
 

boobook

Well-Known Member
needs a new calculator or a new sense of humor.

Electrical Calculator - Heavy Duty

1660681288771.png
 

Toyasaurus

Well-Known Member
I`m guessing you use bugger all power, have a solar array or are off grid, excellent.

For those who arn`t, some of us are just trying to help.
 

Petunia

Well-Known Member
For those who arn`t, some of us are just trying to help.
Ok !

Now where I would start to try to help is ''How much do you want to run?" work backwards, be realistic, toasters, kettles and hair conditioner will take some juice, jigawatts, angry pixies.
Add that up, no good running out of Killer What's when you plug the last appliance in.
EXAMPLE!! I have a 1 Killer What inverter in my car, it runs a 500W drill, yet a 550w angle grinder goes all spastic trying to start, don't bother to tell me why!

Shed .... so we not running cable down a Swiss snow covered mountain slope for a thousand meters, is a shed, logically panel/s may or may not be mounted on the roof. 5 meter run? maybe? 12v quite fine over 5m [not the swiss mountain slope, remember, where i would deffo go 48v for distance{ you may win that one} ]

After we find a Killer What total, we apply the magic calculator [god forbid cheap jack cask vinegar {vomit} ] find our battery storage value/volume and our Wattage value on our panels to put back what we take out ?

It's been a pleasure to be of such unbridled service, Thank you, Please call again.
 
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