Small DIY or plug n play ( Australia)

[Iristocratmusic]

Hi all

I’m from an area a few hours drive south of Sydney on the eastern coast of Australia.

We have a cabin in an isolated farming area. No mains power or water etc.

The house still has a solar set up..: but the agm batteries went about 5 yrs ago… just in time for us to buy the place.

We got quotes to replace the agm batteries but it was so expensive.

The solar panels are also quite old… 12-20 yrs old. 3 different types.

I’m seeking advice on the best solar upgrade option.

Till now I have run our Honda 2200 inverter generator at night for lights or to run the vacuum / washing machine. The fridge is gas. Oven is gas. Hot water is gas.

My wife and I are preparing to spend the next 4 months there.

I don’t want to be running the generator when the solar options are so much better.

I have looked at will’s videos… (really informative so from us in Australia:thank you ).

I’ve considered a plug and play unit… the bluetti 200max or ac300;

But then it doesn’t really need to be Portable.!

So I’ve looked a little at building my old w. 24v system w 240v inverter .

I don’t know much about electronics though… but al willing to learn and will have some time

In that 4 month period.. but ideally I need to buy the solar gear soon to be ready.

The expected load will be:

Lights ( led house lights … maybe 10 max)

Charging phones , laptops , tool batteries

Sound (music) system

Modem

Occasional :

Washing machine

Vaccuum

Guitar amps

Tv

Ceiling fans



After the 4 month living off grid we will be back to city work only returning every

2 months for a few days.



Any suggestions / ideas greatly appreciated

Thx

Luke ( bemboka , Nsw Australia)

 

[Rednecktek]

The washing machine and vacuum are going to be your heavy hitters inverter-wise. Do a search for "Blurb time" under my username and that'll help point you in the right direction.

Fortunately if your 2kw generator is doing enough, then a 3kw/24v or step up to a 48v system should give you comfortable overhead. Max out your solar and the Power Audit form will give you an idea of battery capacity needed.

 

[wattmatters]

Budget?

 

[SamDeleted]

Washing machine

Vaccuum

For me (depending on budget).... I would size a solar system for your smaller loads, lights, phone chargers, modem, tv ect . And then when you want the hoover/washing machine run your generator


The difference in price between a system for your small loads , and a system that can handle everything is going to be huge




What kind of space have you got for solar panels, is it good south facing , no shade ?

 

[wattmatters]

What kind of space have you got for solar panels, is it good south facing , no shade ?

You want north facing in Australia (except in places like Darwin where south is pretty good because of its tropical latitude and the wet season).

 

[SamDeleted]

You want north facing in Australia (except in places like Darwin where south is pretty good because of its tropical latitude and the wet season).

Yes sorry forgot they're upside down over there in Aus

 

[wattmatters]

Yes sorry forgot they're upside down over there in Aus

 

[Iristocratmusic]

Hey people
Thx for your responses.
Really great to wake up and check the forum to have these!
Regarding budget…in Aust dollars up to $2000.
Regarding good sun: yes really good position.
And yes north facing down here but got what you meant

Thanks
For suggestions on using the generator for occasional large loads and to size the system
for lighter loads ( led lights: phones / batteries etc)

System size
The suggestion on a 3kw/ 24v sounds good to me.
The system will be running a 240v inverter.
Wondering Why is 24v preferred over 12v.
(I don’t have any 12v appliances) just a general rooky question

another point/
Our generator shed is about 15 mtrs from the house… is this ok…if I have the system this far away from the existing circuit board?

Otherwise I have the option of installing it right next to the house.

The old solar panels are still up.(15-20 yrs old)
Should I buy new ones? To match the new system?

Thanks again
Luke

 

[Iristocratmusic]

Budget?

$2000 aust

 

[Rednecktek]

The suggestion on a 3kw/ 24v sounds good to me.
The system will be running a 240v inverter.
Wondering Why is 24v preferred over 12v.

Because watts = volts X amps, so if you draw 3000w at 12v you need a wire and fuses for 250a, whereas if you're doing it from a 24v system you only need wires and fuses for 125a which is MUCH smaller, cheaper, and easier to manage. Likewise if you went for a 48v based system it would only be 70a worth of wire and fuses, and if you ever decided you needed more power you can add another inverter off the same battery. 24v was kinda an interim size and the market has really moved away and towards the 48v world so getting stuff is a mite easier than 24v.

 

[wattmatters]

$2000 aust

That makes life a bit challenging. That will barely cover a battery with the sort of discharge current capacity you are looking at.

 

[otownjeff]

My Blue Carbon all-in-one 3kw 24v system cost USD1400. Eight 200w solar panels plus controller/battery/inverter are one unit. It would run your small loads around the clock on decently sunny days. If it rained all day you could beef up the battery before evening with your generator.

 

[Iristocratmusic]

That makes life a bit challenging. That will barely cover a battery with the sort of discharge current capacity you are looking at.

What size battery would I need for a 3000w 24v system? I can look into prices here.

 

[Iristocratmusic]

My Blue Carbon all-in-one 3kw 24v system cost USD1400. Eight 200w solar panels plus controller/battery/inverter are one unit. It would run your small loads around the clock on decently sunny days. If it rained all day you could beef up the battery before evening with your generator.

Thanks … I will need to see if blue carbon are for sale here. The price point is certainly great if that includes solar panels?
Bluetti and Ecoflow are available here.

But im also looking at the diy pathway tooX

 

[Iristocratmusic]

What size battery would I need for a 3000w 24v system? I can look into prices here.

I do have 1700w selectronic sine wave inverter and a decent solar charge controller from the old system I could re commission. Then I can focus funds on a couple of quality lifepo4 batteries.
These units are about 15 yrs old though … so I May need to beef up my budget and buy some new gear like victron. What do you think?

 

[Iristocratmusic]

Thanks for your suggestions as I work this out.
Here are 3 pics of the old system
Panels on roof
System control centre: inverter ( olive green) and charge controller (blue)
In situ: located outside the cabin
Id love to recycle what I can …but really not sure what I can use

 

[wattmatters]

What size battery would I need for a 3000w 24v system? I can look into prices here.

A battery needs to meet two two requirements:

- energy capacity (how long it will last)
- discharge capacity (how much power it can deliver)

The former depends on what your expected average power draw will be and for how long you need to keep stuff running from the battery.

With the latter, if you expect your battery to support loads up to 3 kW (or brief surges beyond that), then it better have the ability to deliver enough current.

Adding say 10% for DC->AC losses, that's 3.3 kW on the DC side. At a "nominal" 24 V, that's 137.5 amps. So you'll need a battery with a BMS rated to supply at least that much current. Generally the higher current rated batteries are also bigger capacity batteries, which are more expensive. I'd expect a 200 Ah 24 V battery would be the minimum.

 

[50ShadesOfDirt]

It costs you nothing to go ahead and run through the design steps ... a few calculations, power audit, and such will help you know what an "ideal" system is.

From there, you can do what-if's to keep parts of the old (possibly piece-meal?) system components, or choose to go with all new, all mostly trouble-free components.

The generator is a key backup component to your system, so that part is mostly done. Solar panels are there, but you'll need to poke around with them and get numbers off of each set, and figure out how they were layed out (how many "strings" of what kinds of panels). I'd investigate each existing component, and make a listing of it all ... post it back here if ok with sharing the info.

The design steps:

1. Go here, and enter in each appliance's values (watts, hours/day you want to run it, etc.):
https://unboundsolar.com/solar-information/offgrid-calculator

2. Go here, using numbers from above, and fiddle with various entries/components, and you'll see in real-time what your system component (inverter, mppt, panel) sizing is:
https://www.altestore.com/store/calculators/off_grid_calculator/

There are many similar website pages/calculators, but these two pages should help you get through most of the necessary calculations. This helps you quickly decide if you can do what you want to do, and you can vary component choices for what-if scenarios.

This is remote, off-grid, so a small, standalone system would likely consist of an AIO inverter, a battery-bank (even if just one battery for now), and solar panels, along with connecting bit & bobs (cables, fuses, etc.); generator would be a backup to recharge battery-bank if solar not cooperating, or if powering large occasional loads.

Reference voltage (as others have mentioned) is 12v, 24v, or 48v ... don't know what it's like sourcing components down under, but a 12v or 24v is easy to do, especially if power needs and distances are small. 48v is for larger needs & distances, at more cost.

See Will's videos & diagrams for example systems, under "DIY Solar ..." drop-down list at top of this forum.

Hope this helps ...

 

[Iristocratmusic]

A battery needs to meet two two requirements:

- energy capacity (how long it will last)
- discharge capacity (how much power it can deliver)

The former depends on what your expected average power draw will be and for how long you need to keep stuff running from the battery.

With the latter, if you expect your battery to support loads up to 3 kW (or brief surges beyond that), then it better have the ability to deliver enough current.

Adding say 10% for DC->AC losses, that's 3.3 kW on the DC side. At a "nominal" 24 V, that's 137.5 amps. So you'll need a battery with a BMS rated to supply at least that much current. Generally the higher current rated batteries are also bigger capacity batteries, which are more expensive. I'd expect a 200 Ah 24 V battery would be the minimum.

Thanks … that’s great info.

 

[Iristocratmusic]

It costs you nothing to go ahead and run through the design steps ... a few calculations, power audit, and such will help you know what an "ideal" system is.

From there, you can do what-if's to keep parts of the old (possibly piece-meal?) system components, or choose to go with all new, all mostly trouble-free components.

The generator is a key backup component to your system, so that part is mostly done. Solar panels are there, but you'll need to poke around with them and get numbers off of each set, and figure out how they were layed out (how many "strings" of what kinds of panels). I'd investigate each existing component, and make a listing of it all ... post it back here if ok with sharing the info.

The design steps:

1. Go here, and enter in each appliance's values (watts, hours/day you want to run it, etc.):
https://unboundsolar.com/solar-information/offgrid-calculator

2. Go here, using numbers from above, and fiddle with various entries/components, and you'll see in real-time what your system component (inverter, mppt, panel) sizing is:
https://www.altestore.com/store/calculators/off_grid_calculator/

There are many similar website pages/calculators, but these two pages should help you get through most of the necessary calculations. This helps you quickly decide if you can do what you want to do, and you can vary component choices for what-if scenarios.

This is remote, off-grid, so a small, standalone system would likely consist of an AIO inverter, a battery-bank (even if just one battery for now), and solar panels, along with connecting bit & bobs (cables, fuses, etc.); generator would be a backup to recharge battery-bank if solar not cooperating, or if powering large occasional loads.

Reference voltage (as others have mentioned) is 12v, 24v, or 48v ... don't know what it's like sourcing components down under, but a 12v or 24v is easy to do, especially if power needs and distances are small. 48v is for larger needs & distances, at more cost.

See Will's videos & diagrams for example systems, under "DIY Solar ..." drop-down list at top of this forum.

Hope this helps ...

Yes; much appreciated… I will crunch some numbers w those links you added.. good place to start. I will ‘poke around’ with the pv panels and find out how they’re wired.
If I want to test then what is the best way?
I have a volt meter.
Thx