Solar, inverter, battery thread

[Düber]

Design modifications at Medupi and Kusile: Peak performance unlikely to ever be achieved

Much has been written about the cost and time overruns at Eskom’s flagship new-build mega-projects – the Medupi and Kusile coal-fired power stations in South Africa. This article focuses on the boiler plant design defects and the status of rectification work currently in progress.

www.dailymaverick.co.za

I will be investing in an online system soon. This is going to go for another five years and I’m gatvol of it. Since 2008!

If you can afford to do it, it will be money well spent. The problems at Eskom are bigger than a quick 5 year fix.

 

[biometrics]

Lol if you think it will be fixed in five years you're an optimist.

And that is why I decided to go for it. Not as large as you and @Spizz went, targetting between R20k and R40k. My needs are less and not doing PV for now.

 

[Sinbad]

And that is why I decided to go for it. Not as large as you and @Spizz went, targetting between R20k and R40k. My needs are less and not doing PV for now.

Make sure you have the option to go towards PV with the system though. Electricity prices are going to skyrocket and the price of PV tech is coming down.

 

[biometrics]

I’m going to work out my constant and peak usage this weekend but a rough calculation tells me I may be using a constant 1kW. So a 3.5kWh lithium battery should last three hours. This should charge back to 100% at 60A in two hours. If I boil the kettle then I should be ok with a 5kW inverter.

These aren’t researched, just browsing, but for example I could use:

Pylontech Lithium Ion 3.5kW US3000C Battery

This is Pylontech's new US3000C with a DOD (depth of Discharge) of 95% The Lithium Ion 3.5kW US3000 battery is the recommended battery for your solar energy storage system

www.inverter-warehouse.co.za

and

Growatt SPF5000TL

The Growatt SPF 3000-5000TL HVM series of inveters are ideal for Off-Grid Solar, or Grid Connected applications with full system monitoring.

www.inverter-warehouse.co.za

For R18,500 + R11,500 = R30,000.

I’m guessing the db components and installation is another R10,000.

So R40,000 total.

Due to the charge time this should get me through level 4 load shedding without too much concern. Higher than that and have to start conserving.

Does that sound about right?

 

[biometrics]

Make sure you have the option to go towards PV with the system though. Electricity prices are going to skyrocket and the price of PV tech is coming down.

See above.

Looks like all these type inverters do both grid and solar, couldn’t find one that only does grid (was hoping it is cheaper).

 

[Rudolph Hart]

I’m going to work out my constant and peak usage this weekend but a rough calculation tells me I may be using a constant 1kW. So a 3.5kWh lithium battery should last three hours. This should charge back to 100% at 60A in two hours. If I boil the kettle then I should be ok with a 5kW inverter.

These aren’t researched, just browsing, but for example I could use:

Pylontech Lithium Ion 3.5kW US3000C Battery

This is Pylontech's new US3000C with a DOD (depth of Discharge) of 95% The Lithium Ion 3.5kW US3000 battery is the recommended battery for your solar energy storage system

www.inverter-warehouse.co.za

and

Growatt SPF5000TL

The Growatt SPF 3000-5000TL HVM series of inveters are ideal for Off-Grid Solar, or Grid Connected applications with full system monitoring.

www.inverter-warehouse.co.za

For R18,500 + R11,500 = R20,000.

I’m guessing the db components and installation is another R15,000.

So R35,000 total.

Due to the charge time this should get me through level 4 load shedding without too much concern. Higher than that and have to start conserving.

Does that sound about right?

No. 18 500 + 11 500 = 30 000, not 20 000. So total is 45 000.

 

[biometrics]

No. 18 500 + 11 500 = 30 000, not 20 000. So total is 45 000.

Lol, I was fixing as you posted. Also reduced the components and installation as I figured it's not such a complex setup. So estimating R40,000.

 

[biometrics]

When the grid is available can the house draw more than the inverter or is that the max whether on grid or battery?

 

[Johnatan56]

When the grid is available can the house draw more than the inverter or is that the max whether on grid or battery?

Do check whether Hermanus has the same rules as CT in terms of max inverter size/what it can pull from the grid.

 

[Tinuva]

When the grid is available can the house draw more than the inverter or is that the max whether on grid or battery?

If it is a hybrid inverter, house cant draw more than the inverter can handle. The reason is, hybrid inverters mix multiple input sources at the same time. So the protected output wont do more than the rated rating. Even then, you dont want to run max at that capacity the whole time, only spikes.

That growatt you looking at is dirt cheap, but then also that shop says out of stock.

Still think Sunsynk is a better option

 

[biometrics]

If it is a hybrid inverter, house cant draw more than the inverter can handle. The reason is, hybrid inverters mix multiple input sources at the same time. So the protected output wont do more than the rated rating. Even then, you dont want to run max at that capacity the whole time, only spikes.

That growatt you looking at is dirt cheap, but then also that shop says out of stock.

Still think Sunsynk is a better option

Budget is limited, I'm trying to spend max R40k. Can you suggest an inverter + battery pair for my budget (components and installation included)? I'd like to be able to use more than the inverter rating when on-grid (so a pass-through inverter?). When off-grid I want to use say 1kW continuously with short peaks for a kettle/oven/microwave/iron staying within the inverted limit and obviously cognizant to limit heavy loads to save the battery.

If it supports solar that would be nice for the future but it's not all that important to me as 40% of my electric bill is service fees I can't get rid of anyway. We only used 410 kWh in January, so don't use all that much.

 

[biometrics]

Do check whether Hermanus has the same rules as CT in terms of max inverter size/what it can pull from the grid.

Nah, not telling them.

 

[Tinuva]

Budget is limited, I'm trying to spend max R40k. Can you suggest an inverter + battery pair for my budget (components and installation included)? I'd like to be able to use more than the inverter rating when on-grid (so a pass-through inverter?). When off-grid I want to use say 1kW continuously with short peaks for a kettle/oven/microwave/iron staying within the inverted limit and obviously cognizant to limit heavy loads to save the battery.

If it supports solar that would be nice for the future but it's not all that important to me as 40% of my electric bill is service fees I can't get rid of anyway. We only used 410 kWh in January, so don't use all that much.

Well mostly I just dont know Growatt, it could befine.

That said, its a hybrid, so you can only use 5kW on it.

As for using a kettle or microwave on top of 1kW base load while on battery....I think that wont work with a single US3000c, but I might be wrong. You actually want to 2x batteries to be able to handle the AMPs. Its a pylontech specific thing. I have 2x US3000b batteries which is why I can do that, as they both work fine with the load in parallel.

Other brands like Hubble, you can do that on a single batter.

Maybe you should explain better why you want to use more than 5kW while Eskom is available. Like what is your use case/example?

 

[biometrics]

Maybe you should explain better why you want to use more than 5kW while Eskom is available. Like what is your use case/example?

I don't quite get the different inverter types.

Bottom line, when there is Eskom I want to use that with no limit. When there isn't I want to have the backup power switched to automatically.

When it's on battery I expect to use no more than 1kW continuous, with the occasional 5-20 minute peak using a 2kW kettle or a 3kW stove (not at the same time).

 

[Tinuva]

I don't quite get the different inverter types.

Bottom line, when there is Eskom I want to use that with no limit. When there isn't I want to have the backup power switched to automatically.

When it's on battery I expect to use no more than 1kW continuous, with the occasional 5-20 minute peak using a 2kW kettle or a 3kW stove (not at the same time).

ok I think you need to understand the limitations of different types of inverters and what you can do on different budgets and then make a decision between that.

If you want to use max that Eskom give and this is for devices on the inverter, you can go for a cheaper non-hybrid axpert inverter, that is in online mode. Then it just passes through Eskom and you can do what you want. The downside on this inverter is, when you later on add solar, if your solar only provide 300w but your usage at the time is 301w, the inverter will get all 301w from Eskom, where as a hybrid inverter will mix, it will take the 300w generated by the solar 1st and then that extra 1w needed from Eskom, saving you as much as it can.

If you want to use 8kW when Eskom is available on a hybrid, some of your stuff should not be on the inverter.
Like geysers, electric stoves, ovens, etc. is best kept on Eskom only power.
Stove you should consider going gas, then you dont have an issue with it on the inverter, so you can use it any time regardless.

Also, in our house, with less power usage than you, our base load is 550w. This is with 3 fridges, 2 laptops with 3 external monitors and sometimes even the TV and whatever lights, then maybe, it goes up to 770w but during work hours its 350-550w base load.

When I made up our order for a 5kW inverter and the 2 batteries, my wife was outraged when I said you can only use 1 big appliance at a time. She was adament, for the price we pay, we must be able to use more at a time.
I sat her down and said, well fine we can go for 8kW inverter in parallel with a 2nd and add more power, but then the cost rise from what we can afford to double that. She quickly realized I have done my homework and then relaxed and accepted the fate. And you know what, it really haven't been an issue. We have been fine with our limitations. The difference is, when the street is out, we stay on and go on with life forgetting about loadshedding when we not out and about.

I hope that helps you understand better.

 

[biometrics]

ok I think you need to understand the limitations of different types of inverters and what you can do on different budgets and then make a decision between that.

If you want to use max that Eskom give and this is for devices on the inverter, you can go for a cheaper non-hybrid axpert inverter, that is in online mode. Then it just passes through Eskom and you can do what you want. The downside on this inverter is, when you later on add solar, if your solar only provide 300w but your usage at the time is 301w, the inverter will get all 301w from Eskom, where as a hybrid inverter will mix, it will take the 300w generated by the solar 1st and then that extra 1w needed from Eskom, saving you as much as it can.

If you want to use 8kW when Eskom is available on a hybrid, some of your stuff should not be on the inverter.
Like geysers, electric stoves, ovens, etc. is best kept on Eskom only power.
Stove you should consider going gas, then you dont have an issue with it on the inverter, so you can use it any time regardless.

Also, in our house, with less power usage than you, our base load is 550w. This is with 3 fridges, 2 laptops with 3 external monitors and sometimes even the TV and whatever lights, then maybe, it goes up to 770w but during work hours its 350-550w base load.

When I made up our order for a 5kW inverter and the 2 batteries, my wife was outraged when I said you can only use 1 big appliance at a time. She was adament, for the price we pay, we must be able to use more at a time.
I sat her down and said, well fine we can go for 8kW inverter in parallel with a 2nd and add more power, but then the cost rise from what we can afford to double that. She quickly realized I have done my homework and then relaxed and accepted the fate. And you know what, it really haven't been an issue. We have been fine with our limitations. The difference is, when the street is out, we stay on and go on with life forgetting about loadshedding when we not out and about.

I hope that helps you understand better.

I doubt I will ever go solar at this house, so I am removing that from consideration. Ok, so I need a "non-hybrid axpert inverter, that is in online mode".

I have a smart plug that shows the watts being used. Will do an audit this weekend. The base load was just a rough top end calculation last night.

 

[biometrics]

Btw I see there is a Mecer branded Axpert. Is this any good. From my experience with Mecer in the 90's I have stayed far away from them since.

 

[Tinuva]

Btw I see there is a Mecer branded Axpert. Is this any good. From my experience with Mecer in the 90's I have stayed far away from them since.

There are lots of different Axperts and then even more with different brands putting their logo on and selling them.
There were so many different options it made me go

Anyways, I looked again at https://www.inverter-warehouse.co.z...rs-1/products/growatt-hybrid-inverter-spf5000 and I think I confused it with https://www.sustainable.co.za/growatt-spf-5000tl-hvm-p-5kva-5kw-48v-hybrid-inverter-with-wifi.html

The latter is a true hybrid, but the one you linked is not. Both are spf-5000tl-hvm but the latter is spf-5000tl-hvm-p.

So maybe you ok with that initial idea. Just need to go with different batteries, 1x pylontech might not work for a burst to 3kW. 2x US2000s might work.

 

[Spizz]

ok I think you need to understand the limitations of different types of inverters and what you can do on different budgets and then make a decision between that.

If you want to use max that Eskom give and this is for devices on the inverter, you can go for a cheaper non-hybrid axpert inverter, that is in online mode. Then it just passes through Eskom and you can do what you want. The downside on this inverter is, when you later on add solar, if your solar only provide 300w but your usage at the time is 301w, the inverter will get all 301w from Eskom, where as a hybrid inverter will mix, it will take the 300w generated by the solar 1st and then that extra 1w needed from Eskom, saving you as much as it can.

If you want to use 8kW when Eskom is available on a hybrid, some of your stuff should not be on the inverter.
Like geysers, electric stoves, ovens, etc. is best kept on Eskom only power.
Stove you should consider going gas, then you dont have an issue with it on the inverter, so you can use it any time regardless.

Also, in our house, with less power usage than you, our base load is 550w. This is with 3 fridges, 2 laptops with 3 external monitors and sometimes even the TV and whatever lights, then maybe, it goes up to 770w but during work hours its 350-550w base load.

When I made up our order for a 5kW inverter and the 2 batteries, my wife was outraged when I said you can only use 1 big appliance at a time. She was adament, for the price we pay, we must be able to use more at a time.
I sat her down and said, well fine we can go for 8kW inverter in parallel with a 2nd and add more power, but then the cost rise from what we can afford to double that. She quickly realized I have done my homework and then relaxed and accepted the fate. And you know what, it really haven't been an issue. We have been fine with our limitations. The difference is, when the street is out, we stay on and go on with life forgetting about loadshedding when we not out and about.

I hope that helps you understand better.

Thanks for this. Good explanation.

 

[Spizz]

I doubt I will ever go solar at this house, so I am removing that from consideration. Ok, so I need a "non-hybrid axpert inverter, that is in online mode".

I have a smart plug that shows the watts being used. Will do an audit this weekend. The base load was just a rough top end calculation last night.

What is this plug you speak of? I'm keen to know how much W I use at any one time in the house.