Here's 250k, design an off grid system

[Harmonic]

If you had 250k to play with and had the below constraints, what would you buy?

Constraints

• Budget 250k
• Max instantaneous load, 7kW
• Average usage per day, 10kWh with 70% of this used during daylight hours
• No grid backup
• Resiliant in the case of a panel, battery or inverter failing
• The system has gas geysers, water heating doesn't need to be considered
• Pumping water is not required
• A suitable generator has already been acquired, but design wise, more minimal generator usage is desired

 

[swakop_toe]

Solar Power Complete Kit Victron Lithium Giga

This is a 6.15 kWp solar system, a 5 kVA inverter, with an 11.3 kWh battery, sufficient for a medium-sized household. This kit is designed to expand your system i

sunstore.co.za

You may choose to double up on the batteries.
Add a decent 6kW+ generator with autostart that the inverter can start when the batteries reach the preset max. DoD.

 

[RonSwanson]

If you had 250k to play with and had the below constraints, what would you buy?

Constraints

• Budget 250k
• Max instantaneous load, 7kW
• Average usage per day, 10kWh with 70% of this used during daylight hours
• No grid backup
• Resiliant in the case of a panel, battery or inverter failing
• The system has gas geysers, water heating doesn't need to be considered
• Pumping water is not required
• A suitable generator has already been acquired, but design wise, more minimal generator usage is desired

• 2x 5K Sunsynk
• 5x Hubble AM-2
• 12-14K Panels
• Installation and letter of goodbye to the municipality

If I can get the UK 3.6K Sunsynk with the 7K MPPT, then I'd opt for two of those instead.

Edited panels to match inverters.

 

[Mike Hoxbig]

If you had 250k to play with and had the below constraints, what would you buy?

Constraints

• Budget 250k
• Max instantaneous load, 7kW
• Average usage per day, 10kWh with 70% of this used during daylight hours
• No grid backup
• Resiliant in the case of a panel, battery or inverter failing
• The system has gas geysers, water heating doesn't need to be considered
• Pumping water is not required
• A suitable generator has already been acquired, but design wise, more minimal generator usage is desired

In the other thread you said your usage is much higher than that...

1350kWh a month. That's mainly used by three geysers and two boreholes, one for irrigation and one for drinking water. Don't have municipal water. 25 odd outside lights but they've all been fitted with 2W leds. Gas for cooking but we still use the electric oven often.

Not sure how you're going to get away with 10 kWh per day when you're running 3 geysers and 2 boreholes?

 

[maumau]

In the other thread you said your usage is much higher than that...

Not sure how you're going to get away with 10 kWh per day when you're running 3 geysers and 2 boreholes?

@Harmonic, the internet never forgets, especially what you said yesterday ........

 

[Snyper564]

@Harmonic, the internet never forgets, especially what you said yesterday ........

Unless its two different properties etc

 

[Iwojima]

View attachment 1310756

Unless its two different properties etc

Or perhaps this theoretical system is not reflective of his current needs, but future ones?

 

[Snyper564]

Or perhaps this theoretical system is not reflective of his current needs, but future ones?

or this

 

[Mike Hoxbig]

Apologies, wasn't taking a dig at @Harmonic. Just a bit of missing context maybe...

 

[itareanlnotani]

10kW panels
8kW Sunsunk
20kWh battery

CoC + Signoff. 250k

I honestly wouldn't bother with redundancy for the inverter.

 

[Harmonic]

In the other thread you said your usage is much higher than that...

Not sure how you're going to get away with 10 kWh per day when you're running 3 geysers and 2 boreholes?

@Harmonic, the internet never forgets, especially what you said yesterday ........

It's not for my current, horribly energy inefficient rental

 

[Harmonic]

• 2x 5K Sunsynk
• 5x Hubble AM-2
• 6.4 - 6.5K Panels
• Installation and letter of goodbye to the municipality

If I can get the UK 3.6K Sunsynk with the 7K MPPT, then I'd opt for two of those instead.

One question, if you do run two say 5kw inverters, do they both run on the same circuit for say a max load of 7kw?

 

[Harmonic]

10kW panels
8kW Sunsunk
20kWh battery

CoC + Signoff. 250k

I honestly wouldn't bother with redundancy for the inverter.

One thing I'm concerned about is if say the inverter packs up, I'm left with no electricity until either the inverter is fixed or replaced. How reliable are these sunsynk inverters?

 

[RonSwanson]

One question, if you do run two say 5kw inverters, do they both run on the same circuit for say a max load of 7kw?

Yes, they parallel (up to 16 of them) the Load and Grid. 2x 5 will provide 11K load capacity, and 4 MPPTs capable of handling 12.8K solar / wind.
And I somewhat agree with @itareanlnotani , Sunsynk inverters are very reliable, so it's actually overkill (and adds unnecessary complexity, for example that Aux/Gen ports don't parallel). What use case do you have in your home that requires that level of redundancy?

 

[Harmonic]

For some more context, I haven't started thinking of a water supply solution yet, current thinking is to pump the water from a small dam on the property, up a hill and then potentially gravity feed the house. Elevation is probably 20m or so but I don't want to get too caught up with that yet.

In terms of the solar installation, current thinking is a ground based install on a patch of land, maybe 50m from the house. Need to figure out the logistics but was thinking of building a small structure to house the batteries and inverters next to the panels and run the AC lines underground to the house.

 

[RonSwanson]

TBH, for 10kWh per day, one 5.5k Sunsynk is more than enough. Just have to watch out for that peak of 7K, do some smart scheduling.

 

[Harmonic]

Yes, they parallel (up to 16 of them) the Load and Grid. 2x 5 will provide 11K load capacity, and 4 MPPTs capable of handling 12.8K solar / wind.
And I somewhat agree with @itareanlnotani , Sunsynk inverters are very reliable, so it's actually overkill (and adds unnecessary complexity, for example that Aux/Gen ports don't parallel). What use case do you have in your home that requires that level of redundancy?

I'm planning on not connecting to the grid at all. I do have a generator to charge the batteries for say a day or two of inclement weather but don't want to be in a situation where it needs to be run for extended periods of time

 

[Harmonic]

TBH, for 10kWh per day, one 5.5k Sunsynk is more than enough. Just have to watch out for that peak of 7K, do some smart scheduling.

I do a fair amount of wood working, running the table saw and dust extractor at the same time is probably only 4kw but I want to leave some spare for other things in the house plus some margin

 

[kolaval]

In terms of the solar installation, current thinking is a ground based install on a patch of land, maybe 50m from the house.

I hope your property is secure, it sounds like you're advertising take aways

 

[RonSwanson]

I do a fair amount of wood working, running the table saw and dust extractor at the same time is probably only 4kw but I want to leave some spare for other things in the house plus some margin

OK, then an 8K SS with maxed out panels on the MPPTs would be minimum.
You may want to consider a Solis inverter plus some panels at the pump, and then you can rig it to pump unused solar capacity to the Aux when it's not pumping water, great for overcast days.