Good evening all,

 

We currently have 2 x 8KW Deye inverters connected in paralell with 7 x BSL Bull batteries at 52.4v ranging from 100ah to 120ah a battery, total battery capacity has been configured at 700ah. 
 

solar panels are 18 x 450w panels and 12 x 565w JA panels, solar produces 11kw at its peak.
 

Currently, we run 4 geysers at various times of the day starting at roughly 10 am and ending at around 4pm, the problem is that with the geysers running we pull about 7.7kw, this in turn has a knock on effect of not effectively charging the batteries all the way to 100%
 

I am just looking for some input as to whether doing a Geyser Guru conversion on each geyser or purchasing an additional few panels to max out the solar capacity in the inverters. 
 

It is three houses running off the 2 x 8kw inverters and batteries so I am leaning more to actually increasing the panel counts, primarily because we are going to be putting in more batteries and I think we will need more panels anyway to charge the batteries. 
 

But then again, I do see the potential benefit on putting the geysers on their own solar. With that said, how effective is the Solar Guru conversion and is the controller smart? I like the smart home aspect and I like being able to monitor and control devices wherever I am. 😁

Im just worried that we go through the conversion process of the geysers and we still need additional panels to charge more batteries. 🤔

 

 

Personally I am a fan of the “add more panels to existing setup” option. 
 

The additional panels when they are not feeding the geysers can contribute to charging batteries or power other loads. 
 

Panels dedicated to geyser loads will sit idle when not needed.  
 

Nothing technical in my thoughts, just the way I would doing it. 

50 minutes ago, Mercadian said:

Good evening all,

 

We currently have 2 x 8KW Deye inverters connected in paralell with 7 x BSL Bull batteries at 52.4v ranging from 100ah to 120ah a battery, total battery capacity has been configured at 700ah. 
 

solar panels are 18 x 450w panels and 12 x 565w JA panels, solar produces 11kw at its peak.
 

Currently, we run 4 geysers at various times of the day starting at roughly 10 am and ending at around 4pm, the problem is that with the geysers running we pull about 7.7kw, this in turn has a knock on effect of not effectively charging the batteries all the way to 100%
 

I am just looking for some input as to whether doing a Geyser Guru conversion on each geyser or purchasing an additional few panels to max out the solar capacity in the inverters. 
 

It is three houses running off the 2 x 8kw inverters and batteries so I am leaning more to actually increasing the panel counts, primarily because we are going to be putting in more batteries and I think we will need more panels anyway to charge the batteries. 
 

But then again, I do see the potential benefit on putting the geysers on their own solar. With that said, how effective is the Solar Guru conversion and is the controller smart? I like the smart home aspect and I like being able to monitor and control devices wherever I am. 😁

Im just worried that we go through the conversion process of the geysers and we still need additional panels to charge more batteries. 🤔

 

 

What direction do the panels face. Depending on area the peak of 11kW seems a bit low if facing north. 

Hi, 

we are based in Krugersdorp.

We have 24 panels facing West and 6 panels facing north. 

Originally we had the 18 450w panels installed west facing, and then decided to install the additional 12 panels to try and maximise the sun, 6 of these were installed North and 6 where installed west  

originally from the 18 original panels we where getting about 5kw, and now we have gone to +/- 11.. keep in mind this peak happens at about 12:35. 
 

Below is just solar draw from solar assistant:

 

And the full picture showing Load, Grid and PV:

 

 

Our average load requirement before battery and solar is 78kw. Which taking that into account as well I suspect the system is under specced on battery and solar. Especially since we are now trying to go off grid. But I don’t know enough at this point to fully ascertain that factually. So yeah, just trying to figure out the best way to approach this. 

Edited May 1, 20242 yr by Mercadian

8 hours ago, Mercadian said:

Hi, 

we are based in Krugersdorp.

We have 24 panels facing West and 6 panels facing north. 

Originally we had the 18 450w panels installed west facing, and then decided to install the additional 12 panels to try and maximise the sun, 6 of these were installed North and 6 where installed west  

originally from the 18 original panels we where getting about 5kw, and now we have gone to +/- 11.. keep in mind this peak happens at about 12:35. 
 

Below is just solar draw from solar assistant:

 

And the full picture showing Load, Grid and PV:

 

 

Our average load requirement before battery and solar is 78kw. Which taking that into account as well I suspect the system is under specced on battery and solar. Especially since we are now trying to go off grid. But I don’t know enough at this point to fully ascertain that factually. So yeah, just trying to figure out the best way to approach this. 

My 1st suggestion would be to try and get the standing load of over 2kW 24/7 a bit lower. Based on results from various members this level is above average and perhaps worth it to explore means of reducing it. 

The above could help reducing the grid use for the 3-4 hrs per day that you happens in the early morning. This could help to not having to add more panels or 1 or 2 more batteries. 

As you still have capacity left on the 2 Inverters. Extra panels plus more battery power could also reduce this grid use as a 2nd area to improve matters. 

Even if using PV for heating the geysers and being idle the rest of the day will still help and achieve charging the 7 batteries full and reduce grid. 

The 4kW grid tied geyser inverter/controller(R4000) from The sun pays plus 4 panels per geyser would have a great ROI. 

There are actually some adjustments you might do on the inverters. It depends on how much of your PV goes towards non essentials and if you have a setting to prioritise charging the batteries to 100% during the day. It's one thing to check. 

Edited May 2, 20242 yr by Scorp007

Hi, 

 

Thanks for the response. The thing is, this is a three house setup, not a single home, at any given point of time these are the minimum items running:

 

1 x upright fridge

1 x upright freezer

3 x chest freezers

1 x top fridge and bottom freezer

3 x double door fridge freezers

2 x desktop computers

1 x server running various things specially a firewall and media sharing platform

1 x 24 port network switch supplying poe power to 9 access points

1 x internet router

I’m not to stressed about the 2kw average usage, I know it is above average and we are not even starting to use heaters and that yet. Which in my mind will change the picture as well. Not sure if this helps matters any 😁  

 

So basically what I read then is that taking the geysers onto their own solar is then a viable option instead of maxing out panels and doing more batteries?

 

 

 

 

 

 

 

3 hours ago, Mercadian said:

Hi, 

 

Thanks for the response. The thing is, this is a three house setup, not a single home, at any given point of time these are the minimum items running:

 

1 x upright fridge

1 x upright freezer

3 x chest freezers

1 x top fridge and bottom freezer

3 x double door fridge freezers

2 x desktop computers

1 x server running various things specially a firewall and media sharing platform

1 x 24 port network switch supplying poe power to 9 access points

1 x internet router

I’m not to stressed about the 2kw average usage, I know it is above average and we are not even starting to use heaters and that yet. Which in my mind will change the picture as well. Not sure if this helps matters any 😁  

 

So basically what I read then is that taking the geysers onto their own solar is then a viable option instead of maxing out panels and doing more batteries?

This is a lot of information on your load profile. Only you will be able to investigate which loads can be switched off instead of trying to run all loads as before on PV and batteries. 

Also you need to decide what level you need the battery power before the sun can charge to be and use settings to achieve it. 

I can just mention that in the same 4  bedroom house with 7 outside lights on the whole nite and still doing a lot of work in the garage my total consumption went down from 1200 to 300 units a month. PV brought it down to less than 20%.

Sorry but not much help to get you through winter with heaters. 

I hope you already have timers on the geysers to assist with the time of day heating them close to when needed. 

 

Not going to comment on whether you have enough battery etc to go off grid, but can possibly help with the geyser questions. I built my own smart geyser controller, based on a geyserwise thermostat and a Sonoff THR320, all running ESPHome. I use it to dump excess solar into the geyser in the form of hot water, but can also manage them remotely, or automatically using Home Assistant. One important thing I did was to change the element from a 3kW to a 2kW, to reduce the peak draw when the geyser is running, so that the load stays under the threshold of available solar. Doing the same for your 4 geysers could take you from 12kW just in geysers to 8kW or less, depending on which are actually running. Note that this just reduces the peak load from your geysers, but they would obviously have to run longer to achieve the same amount of hot water.

You can find details here: https://mybroadband.co.za/forum/threads/esphome-geyserwise-smart-thermostat.1231463/ Note that if I were to do it again, I'd try really hard to just replace the thermistor with a Dallas DS18b20 1-wire sensor at the tip of the thermostat, rather than futzing with the interposer!

If you want to spend money, you could consider heat pumps as a much more efficient way of heating water (3 times). Given your goal to go offgrid, it would be smarter to reduce your consumption before investing in more batteries. Regardless of the technology you select, having some degree of load control is advisable, whether that is turning off geysers, pool pumps, chest freezers, etc.

9 hours ago, Scorp007 said:

The 4kW grid tied geyser inverter/controller(R4000) from The sun pays plus 4 panels per geyser would have a great ROI. 

That sounds like around R12-14k each, which is about the same price as an equivalent heat pump, I think. But reducing the consumption will pay off by making panels previously dedicated to heating water available for other loads, like charging batteries. And with smart control, you can possibly change thermostats on the heat pumps to run when your batteries are near full, and there is more solar available than needed to fill the batteries.

Edited May 2, 20242 yr by RoganDawes
Add note about longer heating times, as well as suggestion to go with heat pumps.

How old is the system? Have you got graphs from last December and June to compare generation beteeen seasons? Or showing the SOC? Might be you have enough capacity in summer as-is with more sun-hours.

First choice maximize the current system with more panels, ideally facing North, rather than separate systems for each geyser, but with days becoming shorter towards mid June, even that might not be very effective.

Instead of another battery, maybe consider a heat pump for the main house's hot water, especially if it has 2 of the 4 geysers, and if they can be connected in series.

1 hour ago, GreenFields said:

How old is the system? Have you got graphs from last December and June to compare generation beteeen seasons? Or showing the SOC? Might be you have enough capacity in summer as-is with more sun-hours.

First choice maximize the current system with more panels, ideally facing North, rather than separate systems for each geyser, but with days becoming shorter towards mid June, even that might not be very effective.

Instead of another battery, maybe consider a heat pump for the main house's hot water, especially if it has 2 of the 4 geysers, and if they can be connected in series.

I missed the portion of possibly going off grid. As members know I feel my 13yr old heat pump is the best investment I have ever made. Thus my post will change and go this route. Just yesterday I measured how my heat pump used only 33% of the power an element would use to heat from 32 to 56°.

With a 78 kWh consumption per day before solar that is not high for 3 households but cost would be high to get all of it from PV. Here a generator must become part of the end state for those about 10 bad periods of rain in Gauteng. 

As no grid is used for heating the 4 geysers during sunshine time they are the main reason why batteries are perhaps not fully charged during the day. 

Edited May 2, 20242 yr by Scorp007

On 2024/05/02 at 10:55 AM, Scorp007 said:

This is a lot of information on your load profile. Only you will be able to investigate which loads can be switched off instead of trying to run all loads as before on PV and batteries. 

Also you need to decide what level you need the battery power before the sun can charge to be and use settings to achieve it. 

I can just mention that in the same 4  bedroom house with 7 outside lights on the whole nite and still doing a lot of work in the garage my total consumption went down from 1200 to 300 units a month. PV brought it down to less than 20%.

Sorry but not much help to get you through winter with heaters. 

I hope you already have timers on the geysers to assist with the time of day heating them close to when needed. 

 

I put wifi smart timers in a few a years back, for tired of manually changing times on traditional timers when load shedding was so inconsistent, much better to be able to control it via the phone 😁

 

so right now we are getting about 80% charge on the batteries and that does take us until early morning. So we have reduced the number of units we use per day at least. 
 

On 2024/05/02 at 3:40 PM, RoganDawes said:

Not going to comment on whether you have enough battery etc to go off grid, but can possibly help with the geyser questions. I built my own smart geyser controller, based on a geyserwise thermostat and a Sonoff THR320, all running ESPHome. I use it to dump excess solar into the geyser in the form of hot water, but can also manage them remotely, or automatically using Home Assistant. One important thing I did was to change the element from a 3kW to a 2kW, to reduce the peak draw when the geyser is running, so that the load stays under the threshold of available solar. Doing the same for your 4 geysers could take you from 12kW just in geysers to 8kW or less, depending on which are actually running. Note that this just reduces the peak load from your geysers, but they would obviously have to run longer to achieve the same amount of hot water.

You can find details here: https://mybroadband.co.za/forum/threads/esphome-geyserwise-smart-thermostat.1231463/ Note that if I were to do it again, I'd try really hard to just replace the thermistor with a Dallas DS18b20 1-wire sensor at the tip of the thermostat, rather than futzing with the interposer!

If you want to spend money, you could consider heat pumps as a much more efficient way of heating water (3 times). Given your goal to go offgrid, it would be smarter to reduce your consumption before investing in more batteries. Regardless of the technology you select, having some degree of load control is advisable, whether that is turning off geysers, pool pumps, chest freezers, etc.

That sounds like around R12-14k each, which is about the same price as an equivalent heat pump, I think. But reducing the consumption will pay off by making panels previously dedicated to heating water available for other loads, like charging batteries. And with smart control, you can possibly change thermostats on the heat pumps to run when your batteries are near full, and there is more solar available than needed to fill the batteries.

Interesting with the smart controller, I have all out geysers with 2kw elements and using wifi smart controllers, I use sonoff light switches which yes I know also add to the load, but it’s negligible I think. 

Was wondering if I could use a sonoff thermostat relay to monitor water temps and only turn on the geyser when it drops below a certain point and shut off when it reaches a suitable temp. 
 

Depending how that’s configured it might be beneficial.  

Also the pool pump is on a smart timer, that runs between 11am and 1pm now in winter. Also about a 2kw load. 
 

by my recent calculations (and by that I mean very rough based on solar advice web site) we should be using a 15kw grid array, we currently have about 11. 
 

Essentially we can definitely not touch the grid during the day, just need to get out damn generator working to charge the batteries and then we should technically be able to not worry to much about the solar during the day either as the generator can fill in the difference. 

who knows we may even be able to then do charging during rainy and overcast days with little effort. 

On 2024/05/02 at 4:29 PM, GreenFields said:

How old is the system? Have you got graphs from last December and June to compare generation beteeen seasons? Or showing the SOC? Might be you have enough capacity in summer as-is with more sun-hours.

First choice maximize the current system with more panels, ideally facing North, rather than separate systems for each geyser, but with days becoming shorter towards mid June, even that might not be very effective.

Instead of another battery, maybe consider a heat pump for the main house's hot water, especially if it has 2 of the 4 geysers, and if they can be connected in series.

So the system is a few years old, but only recently put in solar assistant which in my mind does a much better job at monitoring that SOLARMAN does. 
 

I could go back more on SOLARMAN, but average is about right for a month, but again, it would depend on the month. 
 

I am still at a point where I’m trying to take a step back and saying before we do anything we actually need to see what happens when rooms are heated with inverter aircons or heaters etc.

 

just trying to get as much information and as many options possible to make informed decisions. That and waiting for an installer my sister in laws knows to come check the configuration of the system and advise if anything on the inverters themselves can be optimised / tweaked to maximise performance.

 

 

 

 

 

 

 

 

28 minutes ago, Mercadian said:

Interesting with the smart controller, I have all out geysers with 2kw elements and using wifi smart controllers, I use sonoff light switches which yes I know also add to the load, but it’s negligible I think. 

Was wondering if I could use a sonoff thermostat relay to monitor water temps and only turn on the geyser when it drops below a certain point and shut off when it reaches a suitable temp. 

The main thing about the smart controller is that it actually has water temperature, not just how long it has run for, and that means that you can dynamically adjust the thermostat as you need to, as well as strategically choosing which geyser to prioritize.

10 hours ago, RoganDawes said:

The main thing about the smart controller is that it actually has water temperature, not just how long it has run for, and that means that you can dynamically adjust the thermostat as you need to, as well as strategically choosing which geyser to prioritize.

That’s my thoughts. Run the coldest geyser earlier and the hottest later. That I think would also increase efficiency. 
 

Will look into this avenue. I’ve gone through your post on my broadband and it looks very comprehensive. 

36 minutes ago, Mercadian said:

That’s my thoughts. Run the coldest geyser earlier and the hottest later. That I think would also increase efficiency. 
 

Will look into this avenue. I’ve gone through your post on my broadband and it looks very comprehensive. 

Feel free to comment on that post if you have any questions. Probably makes sense to keep them in one spot for others to follow.

4 hours ago, RoganDawes said:

Feel free to comment on that post if you have any questions. Probably makes sense to keep them in one spot for others to follow.

Will do. Just need to get logged in again. Seems I forgot my password and it’s giving me grief on the password reset. 
 

any reason for not using the Geyserwise Thermostat with the Tuya WiFi Controller? Or was the WiFi controller not available at the time?

40 minutes ago, Mercadian said:

Will do. Just need to get logged in again. Seems I forgot my password and it’s giving me grief on the password reset. 
 

any reason for not using the Geyserwise Thermostat with the Tuya WiFi Controller? Or was the WiFi controller not available at the time?

I’m cheap! My solution cost under R700 all in, not including the time I spent learning things, whereas the Geyserwise smart solution was more like R3k, I believe.
 

And I didn’t want grief with Tuya talking to the cloud and me talking to the cloud, and nobody talking to each other if my internet connection is not working! 😬 I believe that there is now a local Tuya mechanism for Home Assistant to talk directly, but that was not the case back then.

5 hours ago, RoganDawes said:

I’m cheap! My solution cost under R700 all in, not including the time I spent learning things, whereas the Geyserwise smart solution was more like R3k, I believe.
 

And I didn’t want grief with Tuya talking to the cloud and me talking to the cloud, and nobody talking to each other if my internet connection is not working! 😬 I believe that there is now a local Tuya mechanism for Home Assistant to talk directly, but that was not the case back then.

Fair enough