Generator or Inverter for residential use?

[cfvh600]

I have no idea what the going rate to install panels are. Only reason I did it myself was that it's just a bit of manual labour and nothing technical. Connect four strings, positive to negative and then the eight cables, two from each string, to the inverter.

The technical stuff is splitting the DB, installing change over switches and wiring up the inverter.

And soon they'll be powering your home

 

[AchmatK]

Just did the math and total cost for all equipment, materials and labour, the installation cost for 8kw inverter, 10.5kw batteries and 28 solar panels came to just under R200k.

At an estimated electricity saving of ±R3 200(8 540w x 5hrs/day x R2.50/kwh x 30 days) per month at my current average price of R2.50/kwh, it will take 5.2 years to break even. This reduces as electricity prices increases. Last electricity bill was R4 000.

Was my immigration fund but that's been put on the back burner due to covid.

Correct my maths and assumptions.

Edit

My initial plan was solar and inverter only with batteries only in a year or two but decided to rather just go all in.

 

[RonSwanson]

Just did the math and total cost for all equipment, materials and labour, the installation cost for 8kw inverter, 10.5kw batteries and 28 solar panels came to just under R200k.

At an estimated electricity saving of ±R3 200(8 540w x 5hrs/day x R2.50/kwh x 30 days) per month at my current average price of R2.50/kwh, it will take 5.2 years to break even. This reduces as electricity prices increases. Last electricity bill was R4 000.

Was my immigration fund but that's been put on the back burner due to covid.

Correct my maths and assumptions.

Edit

My initial plan was solar and inverter only with batteries only in a year or two but decided to rather just go all in.

In fairness, you run a relatively large household with a sizable appetite for electricity, so the payback of around 5 years is believable.

My own household only uses 342 Kwh per month maximum, and I calculated my payback on an estimated R160k investment to 11 years (factoring in Eskom increases of 6% p.a).

 

[AchmatK]

Last electricity bill

 

[Saba'a]

Hmm ... will add only 10 panels next year probably.

For me issue wasn't saving electricity but to mitigate loadshedding.

Maybe install the pv panel mounts in the interim but will see.

For now waiting on the inverter. They better update me tomorrow.

 

[thehuman]

In fairness, you run a relatively large household with a sizable appetite for electricity, so the payback of around 5 years is believable.

My own household only uses 342 Kwh per month maximum, and I calculated my payback on an estimated R160k investment to 11 years (factoring in Eskom increases of 6% p.a).

They allow grid tie there ?
2800w of panels should easily cover that with 2 x 1200w grid tie inverters, +- 4.5k ea excludes pannels and installation

 

[RonSwanson]

They allow grid tie there ?
2800w of panels should easily cover that with 2 x 1200w grid tie inverters, +- 4.5k ea excludes pannels and installation

grid tie? You mean selling back to the grid?
I based my calcs on money which I would have spent buying Eskom electricity, not on what I would sell to them, my understanding is that's not possible.

 

[wingnut771]

In fairness, you run a relatively large household with a sizable appetite for electricity, so the payback of around 5 years is believable.

My own household only uses 342 Kwh per month maximum, and I calculated my payback on an estimated R160k investment to 11 years (factoring in Eskom increases of 6% p.a).

why R160k with such low usage? surely you could get a much smaller system like R80k making it 5 years aswell?

 

[Gnome]

In fairness, you run a relatively large household with a sizable appetite for electricity, so the payback of around 5 years is believable.

My own household only uses 342 Kwh per month maximum, and I calculated my payback on an estimated R160k investment to 11 years (factoring in Eskom increases of 6% p.a).

Out of curiosity, do you guys factor in life of batteries? Or how does that work?

I always considered that the big blocker for going this road.
Taking 10 years to break even would mean you need a battery that will last 10 years and not a lot of data around on batteries that can do that and a lot can go wrong in that time.

In other words, does this 11 years for example include risk costs? (sort of like insurance cost)

 

[AchmatK]

Out of curiosity, do you guys factor in life of batteries? Or how does that work?

I always considered that the big blocker for going this road.
Taking 10 years to break even would mean you need a battery that will last 10 years and not a lot of data around on batteries that can do that and a lot can go wrong in that time.

In other words, does this 11 years for example include risk costs? (sort of like insurance cost)

I haven't factored in replacement costs.

What I have done is estimate the useful life I can get from the components.

Solar panels should give me 20 years.
Inverter has a five year warrantee but hopefully it would give me 10 years usage.
Batteries are counted in cycles. I worked out that I would on average do 4 cycles per week or 200 cycles per year and DOD of about 70%. The pylontech batteries will do 6 000 cycles so that's 30 years @ 200 cycles per year. I would probably triple that if i go completely off grid so would be 10 years at 600 cycles per year.

What I will also be doing is saving the money I would have paid in electricity charges every month into a unit trust account to cover me should I need to replace any component or upgrade in future. Putting away R3k every month will be a significant amount in 10 years time.

 

[RonSwanson]

why R160k with such low usage? surely you could get a much smaller system like R80k making it 5 years aswell?

That is what it costs, properly specced 5kVA system, going with the world leader. I received 5 quotes in March ranging from R500k to R110K. Just the batteries alone would be more than 80k. Then there's installation costs and other sundries.

 

[RonSwanson]

Out of curiosity, do you guys factor in life of batteries? Or how does that work?

I always considered that the big blocker for going this road.
Taking 10 years to break even would mean you need a battery that will last 10 years and not a lot of data around on batteries that can do that and a lot can go wrong in that time.

In other words, does this 11 years for example include risk costs? (sort of like insurance cost)

It depends on the cycles, whether or not you are using the batteries everyday, or just for load sheddding. Most lithium batteries would be guarranted for at least 10 years, subject to conditions. And if properly selected and matched, and treated well, they can still deliver substantial power after that.

But I get what you are saying, in ten years' time the battery manufacturer may have been liquidated and not in a position to honor the guarantee, in my own case it's a risk that will need to be accepted. I never factored insurance into it. You raise a good point, should consumers insist on a reputable finance house underwriting the guarantee / warrantee on the batteries? It would certainly drive the costs up.

 

[wingnut771]

Out of curiosity, do you guys factor in life of batteries? Or how does that work?

I always considered that the big blocker for going this road.
Taking 10 years to break even would mean you need a battery that will last 10 years and not a lot of data around on batteries that can do that and a lot can go wrong in that time.

In other words, does this 11 years for example include risk costs? (sort of like insurance cost)

found an interesting article:

Complete Home Battery Guide 2021 — Clean Energy Reviews

Detailed cost comparison and lifecycle analysis of the leading home energy storage batteries. We review the most popular lithium-ion battery technologies including the Tesla Powerwall 2, LG RESU, PylonTech, Simpliphi, Sonnen, Powerplus Energy, plus the lithium titanate batteries from Zenaji and Kilo

www.cleanenergyreviews.info

 

[Saba'a]

It depends on the cycles, whether or not you are using the batteries everyday, or just for load sheddding. Most lithium batteries would be guarranted for at least 10 years, subject to conditions. And if properly selected and matched, and treated well, they can still deliver substantial power after that.

But I get what you are saying, in ten years' time the battery manufacturer may have been liquidated and not in a position to honor the guarantee, in my own case it's a risk that will need to be accepted. I never factored insurance into it. You raise a good point, should consumers insist on a reputable finance house underwriting the guarantee / warrantee on the batteries? It would certainly drive the costs up.

My insurance indicated they can cover battery failure. Haven't pursued it yet as they require 1. COC and 2. Invoice of cost.

Asked Std Bank and Discovery for cover for the inverter system.

 

[Pho3nix]

That is what it costs, properly specced 5kVA system, going with the world leader. I received 5 quotes in March ranging from R500k to R110K. Just the batteries alone would be more than 80k. Then there's installation costs and other sundries.

That sounds very high. Got quoted R90k for a full system a couple months back as well. Mind sharing your quote?

 

[TheChamp]

That sounds very high. Got quoted R90k for a full system a couple months back as well. Mind sharing your quote?

What exactly do you mean by a full system? Full can be very relative, a full system in a one bed flat and a full system in an eight room mansion are two different things.

Going on assumption of a regular household yours sound too well priced.

 

[wingnut771]

What exactly do you mean by a full system?

panels, inverter and batteries?

 

[TheChamp]

panels, inverter and batteries?

Come on...

 

[wingnut771]

What exactly do you mean by a full system? Full can be very relative, a full system in a one bed flat and a full system in an eight room mansion are two different things.

Going on assumption of a regular household yours sound too well priced.

inverter = R15000
6 x 400W panels = R13200
2 x 3.5 pylontech = R42000

Total = R70200

 

[RonSwanson]

That sounds very high. Got quoted R90k for a full system a couple months back as well. Mind sharing your quote?

Everyone has different needs (usage) and objectives (off-grid, Hybrid, for loadshedding or everyday), perceptions of quality, and circumstances (where to store the batteries and inverter, roofing material, roof pitch, ceiling space, degrees off North etc. ). Unless we were aligned on all of these, there would not be any point.