Eskom ridiculous quote to connect!

[Zeo786]

Hi All,

Newbie here,with my first post.

After getting a ridiculous connection fee from eskom(100k to connect only). I've decided after doing my research it'll just be better to get solar and manage my own grid. With a payback option I think I'll be able to pay my system off much quicker if I use the 100k towards the solar.

I need to cater for about 1500kwh per month for 3 houses. It's a new development. A main house with 2 small flats.

This is what I'm looking at and we'll appreciate any advice:

Invertor:

Deye 12kW Hybrid – 3 Phase Inverter

Looking at a 3 phase

Battery: 

3x Alpha 10.1kWh – Lithium-ion Battery

Chose the above because of its 90% Dod with 8000 cycles. Best i could fine.

Solar panels: I'm looking at maxing out the solar panels to so :

29 x Canadian Solar 545W Mono PERC HiKU with MC4-EVO2

I'm looking to generate extra capacity during the day and also to get about 150% coverage for the rainy days.

 

1. Will the above cover my 1500kwh per month with a 750 day and 750night average?

2. The borehole and pool pumps will have their own solar kits.

3. Are the brands chosen good enough?

4. Any recommendation on installers in jhb.

5. My current setup doesn't have an eskom backup yet, but does have space for it in the future if need be. Will the solar system be reliable enough to go full no Eskom

5. Any other advice will be greatly appreciated.

 

Thanks in advance 

 

 

 

[P1000]

100k is not really ridiculous, especially for 3 houses. To be completely off-grid, I suspect your proposed system is not going to be sufficient. Your average daily use is 50kWh, but your storage will be less than 30kWh - so there will definitely be days when you deplete your batteries (unless you live somewhere that never has cloud cover).

[iiznh]

12KW inverter runs optimal with strings of 13 panels. You are looking at 13 / 26 / 39 Panels.

Any reason why you need to have 3 phase? Otherwise you could also consider 2x 8KW inverters in parallel which will give you 16KW and a lot more options to connect more solar strings. 

[Calvin]

27 minutes ago, Zeo786 said:

Looking at a 3 phase

Is there a specific reason to look at 3-phase? If you can avoid it do so - your inverter can presumably handle only 4kW per phase, which means you could be tripping on one phase whilst only using half of your capacity.  I converted my house to single phase when going solar, and bought a single-phase to 3 phase inverter drive to run my 3 phase pump.

Agree with @P1000 - your proposed system is very small for what you want.  You will absolutely need a generator or at least a single phase 60A ESKOM prepaid line to charge the batteries to see you through the cloudy days.

[Piper]

I suspect your 100k is not enough for your batteries.

[Piper]

10 minutes ago, Piper said:

I suspect your 100k is not enough for your batteries.

Sorry,Misunderstood the 100k statement so disregard.

[Buyeye]

I'm not following why he needs a grid interactive inverter when he has no grid connection.

3 axpert max 8kw were made specifically for this scenario, one for each phase? Then an Lpg generator and maybe a windmill?

If you are next to a stream hydro generators are very reliable sources of electricity. 

Anyway I'm always confused when I read that there is no grid connection and we are recommending the latest grid interactive inverters.

[Zeo786]

2 hours ago, P1000 said:

100k is not really ridiculous, especially for 3 houses. To be completely off-grid, I suspect your proposed system is not going to be sufficient. Your average daily use is 50kWh, but your storage will be less than 30kWh - so there will definitely be days when you deplete your batteries (unless you live somewhere that never has cloud cover).

Thanks for the reply. Wanted to know my daily use is about 50kw. That's night and day. Should my batteries be equal to my full daily usage? Or only for night usage I.e 30kwh?

Also why would the batteries be less that 30kwh?

 

[Zeo786]

1 hour ago, Calvin said:

Is there a specific reason to look at 3-phase? If you can avoid it do so - your inverter can presumably handle only 4kW per phase, which means you could be tripping on one phase whilst only using half of your capacity.  I converted my house to single phase when going solar, and bought a single-phase to 3 phase inverter drive to run my 3 phase pump.

Agree with @P1000 - your proposed system is very small for what you want.  You will absolutely need a generator or at least a single phase 60A ESKOM prepaid line to charge the batteries to see you through the cloudy days.

Thanks definitely then going to look at getting an Eskom backup.

 

Point taken on the 3phase. I assumed 3 phase would be better. But it  could trip on the 4kw as you say. I'll look at a single phase invertor. Maybe as suggested 2 x 8kw single phases.

[P1000]

7 minutes ago, Zeo786 said:

Thanks for the reply. Wanted to know my daily use is about 50kw. That's night and day. Should my batteries be equal to my full daily usage? Or only for night usage I.e 30kwh?

Also why would the batteries be less that 30kwh?

 

For off-grid, you would need to be able to last a number of days (exact number depending on where you are located) on only batteries. Having less than the equivalent of one day won't cut it.

90% of 3x10.1kWh is less than 30kWh.

[Zeo786]

10 minutes ago, Zeo786 said:

Thanks definitely then going to look at getting an Eskom backup.

 

Point taken on the 3phase. I assumed 3 phase would be better. But it  could trip on the 4kw as you say. I'll look at a single phase invertor. Maybe as suggested 2 x 8kw single phases.

Just for my understanding The invertors will essentially do all the work of fetching power from either source and charging the batteries as necessary?

Edited April 28, 2022 by Zeo786

[Bobster.]

I have 10kw/h of batteries, for one house, 2 of us living in it. You're way light on batteries for 3 dwellings. And light on the inverter side. 

And how do you apportion the battery power between the 3 dwellings. 

Think of a cold night, everybody home, heaters on, air fryers working, somebody drying their hair, an oven going. 

Next morning it's overcast... 

You need more batteries, a way to handle the fight over who flattened the batteries and turned off everybody else's Netflix, and another source of power - grid or generator. 

If you want to go this route, consider a separate system per dwelling, at least cost it out. Either way you will need more batteries. My rule of thumb, with 10kw/h, is that if I'm fully charged at 16:00 then I'm good until 7:00.  But I have a gas stove, don't run the geyser over night, and if it's overcast the next morning I need to get me some juice from somewhere by 9:00 or so. In my case that'll be the grid. 

[Zeo786]

16 minutes ago, Bobster said:

I have 10kw/h of batteries, for one house, 2 of us living in it. You're way light on batteries for 3 dwellings. And light on the inverter side. 

And how do you apportion the battery power between the 3 dwellings. 

Think of a cold night, everybody home, heaters on, air fryers working, somebody drying their hair, an oven going. 

Next morning it's overcast... 

You need more batteries, a way to handle the fight over who flattened the batteries and turned off everybody else's Netflix, and another source of power - grid or generator. 

If you want to go this route, consider a separate system per dwelling, at least cost it out. Either way you will need more batteries. My rule of thumb, with 10kw/h, is that if I'm fully charged at 16:00 then I'm good until 7:00.  But I have a gas stove, don't run the geyser over night, and if it's overcast the next morning I need to get me some juice from somewhere by 9:00 or so. In my case that'll be the grid. 

Thanks for the advice. Much appreciated. 

Geyser wise I'm looking at gas geysers only. And for heating using a fire place for each unit. No heaters. 

Cooking will be gas and when available power the normal stove.

Is there a way to decide how much each unit can be apportioned with a single phase system?

[system32]

5 hours ago, Zeo786 said:

Thanks for the reply. Wanted to know my daily use is about 50kw. That's night and day. Should my batteries be equal to my full daily usage? Or only for night usage I.e 30kwh?

Also why would the batteries be less that 30kwh?

 

My daily use is about 27kWh, my battery is 20kWh, I have a 20% SoC, so 16kWh usable capacity.
This works 85% of the time, the other 15% I use CoJ prepaid.
The problem is when it rains for a whole day or two or three.
To be 100% off grid, you will need a lot of batteries or a generator.

[Zeo786]

If i take a 2x single phase invertor - can I have a eskom 3 phase supply? Or would that also have to be single phase? 

[nico1]

Hi

What will be your usage profile? will you have tenants in the two flats or family members? since is a new development how did you estimate 1500kwh month usage?

* my 2 cents 

1. I will rather have 3 x 8kw Deye inverters for each house 

2. Borehole and pool pump to be connected on main house 8kw or share with a flat ( you will have a lot of wasted power when is sunny)

3. Install emergency led lights on all houses - additional 3-4 hours light back up in early hours of the morning/when cloudy.

4. Consider running a dedicated light-only back - up system that will last you 2-3 days (to me honestly lights are more important than plugs) should get you thru cloudy days.

5. Pylontech US3000C (3.5kwh) has a 95% DOD >6000cycles 

6. How many aircon and your strategy to run them? 

[Buyeye]

9 hours ago, Zeo786 said:

Thanks for the advice. Much appreciated. 

Geyser wise I'm looking at gas geysers only. And for heating using a fire place for each unit. No heaters. 

Cooking will be gas and when available power the normal stove.

Is there a way to decide how much each unit can be apportioned with a single phase system?

Evacuated solar solar tube collectors seem to have a long life, little or no maintenance with a back up element which can be powered by a back up gas generator for those bad weather conditions. Or backup gas geyser. 

[Zeo786]

5 hours ago, nico1 said:

Hi

What will be your usage profile? will you have tenants in the two flats or family members? since is a new development how did you estimate 1500kwh month usage?

* my 2 cents 

1. I will rather have 3 x 8kw Deye inverters for each house 

2. Borehole and pool pump to be connected on main house 8kw or share with a flat ( you will have a lot of wasted power when is sunny)

3. Install emergency led lights on all houses - additional 3-4 hours light back up in early hours of the morning/when cloudy.

4. Consider running a dedicated light-only back - up system that will last you 2-3 days (to me honestly lights are more important than plugs) should get you thru cloudy days.

5. Pylontech US3000C (3.5kwh) has a 95% DOD >6000cycles 

6. How many aircon and your strategy to run them? 

Thanks Nico, appreciate the advise.

I estimated usage based on my current usage and minused my electric geyser.I know one of the tenants so got their usage as well...and used that as a base line.

They will be tenants. The size of the flats are quite small. 80sqm. So not expecting much usage. Will have usage instructions in the contract etc. 

It makes sense to run 3 invertors. However I'm hoping to get away with 2. 1 for the main house and 1 for the tenants.

The boreholenis shared amongst neighbour's so I'll leave that seperate, but I think you correct to move the pool pump onto the main house.

Will take a look at the emergency led lights.

Wrt to the pylon batteries. The cycles are 6000, since I'm paying it off I was hoping for more cycles to maximize roi. Hence the 8000cycle  on the alphas. 

No aircons in the tenants section. 2 in the main house. I'm hoping if it's hot that means we should be over producing and can run the aircons? 

 

Edited April 29, 2022 by Zeo786

[Zeo786]

5 hours ago, Buyeye said:

Evacuated solar solar tube collectors seem to have a long life, little or no maintenance with a back up element which can be powered by a back up gas generator for those bad weather conditions. Or backup gas geyser. 

I did look at the option of solar with a gas boost, however my investigations with gas geyser I.e the Palermo  is they good enough on their own. I think cost wise it'll be a saving. 

I might consider a 1 x solar geyser to feed all the apartments....boosted by gas  budget pending.

 

Thanks

[Bobster.]

14 hours ago, Zeo786 said:

Is there a way to decide how much each unit can be apportioned with a single phase system?

I think the best you can do is to only back up certain circuits in each dwelling, but even then, depending on inverter and settings, some PV may be diverted to running non-backed up loads rather than charging batteries. This is easier if you have separate inverters and batteries for each dwelling. 

And then you have to rely on the residents to not abuse the backed up circuits. When my system was installed, the installer recommended not backing up the kitchen at all because of the number of high load items in that room. I said to him, well, if I'm desperate enough and stupid enough I'll just run an extension lead into the kitchen and plug the microwave and a hot plate into that. So we agreed to back up the kitchen and we in the house have to discipline ourselves to not abuse the system.

[Buyeye]

2 hours ago, Zeo786 said:

I did look at the option of solar with a gas boost, however my investigations with gas geyser I.e the Palermo  is they good enough on their own. I think cost wise it'll be a saving. 

I might consider a 1 x solar geyser to feed all the apartments....boosted by gas  budget pending.

 

Thanks

I would double check the sums of 3 houses showering twice a day on gas for 10 years. You have to remember we more clear sky days than not. It's just that those few cloudy or rainy days feel like eternity. 

[Zeo786]

13 minutes ago, Buyeye said:

I would double check the sums of 3 houses showering twice a day on gas for 10 years. You have to remember we more clear sky days than not. It's just that those few cloudy or rainy days feel like eternity. 

It'll be 4 gas geysers. 2 for the main house and 1 each for the tenants.

But I get ur point. A solar geyser will reduce the gas usage savign money in the long run. However I need to consider the cost of the solar geysers being almost 25k each. Which is 50k worth of panels. 

[system32]

7 hours ago, Zeo786 said:

Thanks Nico, appreciate the advise.

I estimated usage based on my current usage and minused my electric geyser.I know one of the tenants so got their usage as well...and used that as a base line.

They will be tenants. The size of the flats are quite small. 80sqm. So not expecting much usage. Will have usage instructions in the contract etc. 

It makes sense to run 3 invertors. However I'm hoping to get away with 2. 1 for the main house and 1 for the tenants.

The boreholenis shared amongst neighbour's so I'll leave that seperate, but I think you correct to move the pool pump onto the main house.

Will take a look at the emergency led lights.

Wrt to the pylon batteries. The cycles are 6000, since I'm paying it off I was hoping for more cycles to maximize roi. Hence the 8000cycle  on the alphas. 

No aircons in the tenants section. 2 in the main house. I'm hoping if it's hot that means we should be over producing and can run the aircons? 

 

>The borehole is shared amongst neighbor's so I'll leave that separate, but I think you correct to move the pool pump onto the main house.
The borehole, pool pump, electric geysers can be run on timers so that they run during the day/afternoon and use excess solar.

This is my typical solar consumption.
In the morning solar dumps into the battery and runs load.
In the afternoon runs load but is mostly wasted.
The inverter will only draw what it requires from solar, so there is a huge drop ~13h00
I don't grid feed, but do have timers for pool pump and geysers to run only from 10:00-16:00

[Zeo786]

1 hour ago, system32 said:

>The borehole is shared amongst neighbor's so I'll leave that separate, but I think you correct to move the pool pump onto the main house.
The borehole, pool pump, electric geysers can be run on timers so that they run during the day/afternoon and use excess solar.

This is my typical solar consumption.
In the morning solar dumps into the battery and runs load.
In the afternoon runs load but is mostly wasted.
The inverter will only draw what it requires from solar, so there is a huge drop ~13h00
I don't grid feed, but do have timers for pool pump and geysers to run only from 10:00-16:00

Thanks for this really helps. 

What is your system if u don't mind  me asking?

[Sidewinder]

I'd thought I also chip in. 

Family of 4 with 8kwSS & 10kw of bulls. You maybe need to look at the following.

1)Load shifting. Assumimg no feed-in, so you need to maximize your usage during the day. Run highdraw appliances only during day when sun shines. Washing, dishwasher, tumbledryer, etc. In winter the slowcooker works overtime. But then you need to be a stew/soup kind person! We cook/bake meals in the oven from 1pm, and then just reheat for dinner. Rest on gas cooker. 

2)Geyser. You have plenty of solar power, so use it(during the day) . So i have 2 geysers(in series), and a hefty heatpump, takes 350 litre up to 64 deg, so enough hot water for evening and morning showers for all. 

3)Batteries. 10kW is barely enough (per household) , and you will suffer deficiency during 2 consecutive rainy days. I would recommend 15kW min. Preferably 20 kW per household. 3 batteries will give you 7.5kW of power max, whem solar is not available. 

4)Control. Try and remote control as much as possible, so that you can bypass default setting, e.g. I have an Astute switch for the pool pump, and on cloudy days, when batteries are not full by certain time, i switch off pool pump, no matter where i am. (750W x 8h running saved). So it's about priority - i can skip the pool for 1 day, but not a low battery

5)Monitor. You need a proper system for this (for each system) , also you will get into spots of bother. 

6)Roof/Space. If you have the space for those panels on the main roof, then keep all three inv. together, if distance to flats is not too far. If you roof is not all pointing north, consider using 2 or even 3 dual Mppt inverters, so you can have some east, mostly north and some west, to flatten you generation curve.

Hope some of this is usefull.