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Solar setup for my tenants - thoughts on design?


sunset1
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Hi Folks,

So I am wanting to setup a solar panel system for a rental house we are building. We dont have a huge budget and the ideas is just to cover the basics during load shedding, and offering some things that are needed right now

We are hoping to advertise as a smart house for folks working from home alot. Supplmental solar system, solar geryser, and free internet.

The idea is that the panels provide enough power to basics - lights (LED) throughout house, 2-3 laptops, modem and router. (we have solar geyser). Maybe 1-2Kw max?

We would also like enough battery capacity to power these items for a 3-4hrs at night in case eskom sheds then.

So far I was thinking of the following:

  • An inverter that has wifi communication so I can monitor if anything goes wrong - dont want the folks renting to worry about this or fiddle. Was thinking the new hybrid growatt.
  • Perhaps 2kw of lithium batteries - guess would be 24v system. Be great to have batteries communicate with inverter.
  • 2-4 +/- 500w JA solar panel

I would ultimately create a compartment outside that houses the inverter batteries, modem and router, so i or others can go check and maintain without disrupting tenants.

Would like to stay under 40k.

Any thoughts or ideas about the setup are very welcome as well as product recommendations. thanks!

Edited by sunset1
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Looking at your expected loads I would guess you'd be looking at a maximum load of between 400-900VA, since you are not planning to run any motors you could get away with a modified sine wave inverter which are really cheap.

If you are looking at future proofing the house against long outages I would suggest considering going towards a 3KVA which would be able to cover a fridge and freezer and maybe a small kettle if you don't have gas cooker option? (you would be close to the limit with a kettle so would not recommend that as a consideration). 5KVA would be no worries at all but obviously at a higher cost.

Batteries definitely lithium as you say. Lead acid technology, knowing the power problems in Southern Africa, are a no go IMHO. There are some very good SA designed batteries available, I have most experience with Revov which are very attractive pricing for their second life batteries but they don't have a 24V system yet as a standard product (very soon I'm told). I've used Pylontech for 24V systems and been happy with them.

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21 hours ago, Shadders said:

Looking at your expected loads I would guess you'd be looking at a maximum load of between 400-900VA, since you are not planning to run any motors you could get away with a modified sine wave inverter which are really cheap.

If you are looking at future proofing the house against long outages I would suggest considering going towards a 3KVA which would be able to cover a fridge and freezer and maybe a small kettle if you don't have gas cooker option? (you would be close to the limit with a kettle so would not recommend that as a consideration). 5KVA would be no worries at all but obviously at a higher cost.

Batteries definitely lithium as you say. Lead acid technology, knowing the power problems in Southern Africa, are a no go IMHO. There are some very good SA designed batteries available, I have most experience with Revov which are very attractive pricing for their second life batteries but they don't have a 24V system yet as a standard product (very soon I'm told). I've used Pylontech for 24V systems and been happy with them.

Hi, thanks,

I guess the main issue with the cheaper inverters (modified sine) is the lack of remote monitoring. Seems im best going with a newer 3kv growatt or sunsynk as it can power more in the future should they need.

Will checkout Revov, thanks! :)

 

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1 hour ago, sunset1 said:

I guess the main issue with the cheaper inverters (modified sine) is the lack of remote monitoring. Seems im best going with a newer 3kv growatt or sunsynk as it can power more in the future should they need.

The flip side of this is that there's not much need for monitoring. I used to have such a box - although without solar. If you had that wired into your house and got some lithium batteries into it, then it will  give 4 plus hours protection and there is nothing that needs adjusting. If your tenants decide to increase the load on it then it will either trip or the batteries will run down. Just wire it in so it doesn't feed geysers and the kitchen.

And you know, it does make a difference. We used to have our old inverter and batteries (nicknamed "OKE" - Ons Klein Eskomtjie) and it would keep up some lights, the TV and decoder, the internet connection and we could charge our phones. And that makes a big difference when load shedding is on. It didn't save us money particularly, but there is a value to keeping some lights on and being able to watch Strictly Come Dancing.

Since you haven't finished the house yet, consider a gas stove. That will still work during a load shed, and your tenants can manage the gas. There are plenty of companies now that deliver gas to your door.

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7 hours ago, Bobster said:

The flip side of this is that there's not much need for monitoring. I used to have such a box - although without solar. If you had that wired into your house and got some lithium batteries into it, then it will  give 4 plus hours protection and there is nothing that needs adjusting. If your tenants decide to increase the load on it then it will either trip or the batteries will run down. Just wire it in so it doesn't feed geysers and the kitchen.

And you know, it does make a difference. We used to have our old inverter and batteries (nicknamed "OKE" - Ons Klein Eskomtjie) and it would keep up some lights, the TV and decoder, the internet connection and we could charge our phones. And that makes a big difference when load shedding is on. It didn't save us money particularly, but there is a value to keeping some lights on and being able to watch Strictly Come Dancing.

Since you haven't finished the house yet, consider a gas stove. That will still work during a load shed, and your tenants can manage the gas. There are plenty of companies now that deliver gas to your door.

Hi, thanks good point ideas. I guess on a smaller inverter and battery they would adjust their power usage habits during load shedding when it trips. I just don’t want to have to keep going over and resetting the inverter etc.
hmmm, I need to do some inverter research.


we are doing gas stove and oven. No solar plugs in kitchen is also a good idea.

 

however Maybe going with the 5kw sunsnyk and 2.75 Hubble would solve all the problems?

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12 hours ago, sunset1 said:

Hi, thanks good point ideas. I guess on a smaller inverter and battery they would adjust their power usage habits during load shedding when it trips. I just don’t want to have to keep going over and resetting the inverter etc.
hmmm, I need to do some inverter research.


we are doing gas stove and oven. No solar plugs in kitchen is also a good idea.

 

however Maybe going with the 5kw sunsnyk and 2.75 Hubble would solve all the problems?

Hi, You go the sunsynk and hubble route, you will be on plus or minus R36k. No chance of getting the solar panels if your budget is R40k. Your initial idea of getting a growatt inverter was the best idea. For the price of 5kw Sunsynk, you can get a 5Kw Growatt and four panels. As for the battery, I'm not sure if Hubble works with Growatt, maybe the guys can confirm. 

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12 hours ago, sunset1 said:

we are doing gas stove and oven. No solar plugs in kitchen is also a good idea.

The kitchen is where you have kettles, microwaves and other appliances that draw big loads - even if some of them only draw a big load for a short period. One consequence of this is that if you have too many of those appliances running simultaneously you will overload the backup side of the inverter, which is current limited.

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13 hours ago, sunset1 said:

Hi, thanks good point ideas. I guess on a smaller inverter and battery they would adjust their power usage habits during load shedding when it trips. I just don’t want to have to keep going over and resetting the inverter etc.

Most of them will reset themselves after an overload. They detect the overload, shut down supply, wait a short period and then start up again  - as long as there is battery or PV available. They don't have a breaker that trips on overload. This is not instantaneous, but it's not long (at least not with mine). By the time I'd found my torch, checked the DB board, the system will be restarting.

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1 hour ago, hoohloc said:

Hi, You go the sunsynk and hubble route, you will be on plus or minus R36k. No chance of getting the solar panels if your budget is R40k. Your initial idea of getting a growatt inverter was the best idea. For the price of 5kw Sunsynk, you can get a 5Kw Growatt and four panels. As for the battery, I'm not sure if Hubble works with Growatt, maybe the guys can confirm. 

Saw the five kw growatt is slightly cheaper. 
just wondering what it’s missing compared to the sunsynk.

I’ve heard only good things about sunsynk on here so thought it might be worth spending the extra five thousand for peace of mind.

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If I had the R40k, I would get the following:

Growatt SPF5000TL at R9.5k

4 x Jinko solar Panels 535W at R2990 each

1 x Pylontec US3000C at R16.9k

All that for R38.4k or get one Pylontec US2000C at R12k which will get your total cost to R33.5k and leave you with R6500 to use for cabling and other stuff 

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4 minutes ago, sunset1 said:

Saw the five kw growatt is slightly cheaper. 
just wondering what it’s missing compared to the sunsynk.

I’ve heard only good things about sunsynk on here so thought it might be worth spending the extra five thousand for peace of mind.

Don't compare it to the Sunsynk, it is the same as comparing BMW 320d with a VW golf GTD. they both have 2.0l diesel motors but the two cars are different in so many ways. One is more expensive than the other but both are fun to drive 😀

If the budget allows, go for Sunsynk. My advice is only based on the R40k budget and the property being a rental place. I'm also in the same situation trying to get something for my rental property and will definitely go for a cheaper solution because I want a quick ROi 

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I was thinking similar: Install a 5kW, 10kWh system on our rented out townhouse to make it almost utility independent. The idea is selling the electricity to the tenants at the same or slightly lower rate as the municipality. My horror is that the prepaid meter provider want to take up to 9% of the turnover.

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On 2021/08/28 at 12:43 PM, Beat said:

I was thinking similar: Install a 5kW, 10kWh system on our rented out townhouse to make it almost utility independent. The idea is selling the electricity to the tenants at the same or slightly lower rate as the municipality. My horror is that the prepaid meter provider want to take up to 9% of the turnover.

Just get another provider. Recharger take a flat rate of R25pm instead of a commission in %. Are you sure there is no middle man taking a big chunk? 

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