Another Noob need help on new purchase

[JohanM]

Hi All and thanks for all the contributions

 

I did allot of research and are now planning on buying a DIY kit end of the month. Even with all the research I am still lost.

My current consumption is about 15KW a day. Based in Boksburg.

Biggest users:

0.75kw pool pump, running a hour a day

No geyser, running heat pump 1.1kwh avg, runs about 4 hours on/off

Oven, not everyday

Tumble dryer, get used maybe once a week hour or two

Dishwasher, once a day

Fridge and box freezer

What I would like to do is run as little as possible on grid

Interested in the following from Solar shop but not sure if its the correct inverter for me.

https://www.solar-shop.co.za/diy-kits/375-kodak-vmiii-lithium-ion-solar-kit-5kw-48kwh-storage-246kwp-solar.html?sfdr_ptcid=13151_617_576754735&sfdr_hash=9181f1f178988ec081926eb734344591&gclid=Cj0KCQiA962BBhCzARIsAIpWEL0TGc7Mk-8I3gvmcqnB3pHY5nbOg5WHWSahG5R4ca8YSGLao_GxflUaApGAEALw_wcB

1 x 5kv Axpert Voltronics VMIII Solar Inverter (Kodak branded)

1 x Battery Pylon Cable Pack

6 x 340Wp Canadian Solar PV modules Thinking of adding 2 more or upgrade to a higher Watt

1 x Complete mounting kit (select roof type on checkout) 

2 x Pylon battery brackets

2 x Pylontech Pylon US3000C

1 x MC4 Connector & Splitter Twin Pack ( Kit 1 ) 

1 x K&N Dual String DC Switch Disconnector 25A 220V – 11A 460V (per string)

1 x 4mm2 single-core 50m cable- Black

1 x 4mm2 single-core 50m cable - Red

 

Questions:

1. Can I connect my complete DB board to the inverter, and for eg, when I switch the stove ON it will starting pulling current from grid for the high load

          And IF YES

2. Will it run the stove from the grid and continue run say lights from PV/Battery ( solar shop claims it does blend current)

3. What other option is out there without spending to much extra cash

 

Also have prepaid and don't want something that is going to cause problems.

 

 

 

 

 

[Bobster.]

You would need to split your DB into essential (backed up) and non-essential loads. When there is an outage you will lose the non-essential loads. 

My favourite  topic: Get an updated COC and notify your insurers. 

Troubles with your meter are going to depend on what brand of meter you have and whether or not you export any surplus PV.

To make the most of any of this type of system you have to adjust your way of life to fit. Literally make hay whilst the sun is shining.

Edited February 17, 2021 by Bobster

[JohanM]

33 minutes ago, Bobster said:

You would need to split your DB into essential (backed up) and non-essential loads. When there is an outage you will lose the non-essential loads. 

My favourite  topic: Get an updated COC and notify your insurers. 

Troubles with your meter are going to depend on what brand of meter you have and whether or not you export any surplus PV.

To make the most of any of this type of system you have to adjust your way of life to fit. Literally make hay whilst the sun is shining.

Thanks for your reply, So everything on the non-essential loads will only use grid even when grid and PV is available?

Will use a certified electrician for wiring to get COC.

Using Landis meter and if I go with the Kodak option apparently it can't back feed to grid.  

[Bobster.]

1 hour ago, JohanM said:

Thanks for your reply, So everything on the non-essential loads will only use grid even when grid and PV is available?

This depends on inverter and settings. Certainly my system runs the non-essential loads off of PV when it can. EG today with the pool pump running for 5 hours I have used a total of 0.5 kw/h from the grid.  My pump is on the non-essential side of the DB. I would expect that most modern hybrid inverters are able to do the same.

1 hour ago, JohanM said:

Will use a certified electrician for wiring to get COC.

Using Landis meter and if I go with the Kodak option apparently it can't back feed to grid.  

Well I'm not an expert (not any kind of electrician) but I think you have answered your own question: You'll be OK as long as you don't export. 

[Gerrie]

18 hours ago, JohanM said:

1. Can I connect my complete DB board to the inverter, and for eg, when I switch the stove ON it will starting pulling current from grid for the high load

The inverter is rated 5KW so any load you draw more than 5KW can cause it to trip, like stove and dishwasher on together and then someone also switch on a hairdryer this might suddenly pull 6KW and cause a instant trip. I also think it’s not healthy for the inverter. I had my entire house on my 4KW inverter before and it worked well as we managed it pretty well but unfortunately the human factor sometimes come in and suddenly all the appliances run at the same time, it’s also not healthy for the batteries to draw maximum power. The  VMiii is a off-grid inverter so I don’t think it will blend Eskom and Solar.

[Gerrie]

2 hours ago, Bobster said:

You would need to split your DB into essential (backed up) and non-essential loads. When there is an outage you will lose the non-essential loads. 

I agree splitting the DB is the way to go, it might require a second earth leakage, one for essential side and one for grid side.

[JohanM]

34 minutes ago, Gerrie said:

The inverter is rated 5KW so any load you draw more than 5KW can cause it to trip, like stove and dishwasher on together and then someone also switch on a hairdryer this might suddenly pull 6KW and cause a instant trip. I also think it’s not healthy for the inverter. I had my entire house on my 4KW inverter before and it worked well as we managed it pretty well but unfortunately the human factor sometimes come in and suddenly all the appliances run at the same time, it’s also not healthy for the batteries to draw maximum power. The  VMiii is a off-grid inverter so I don’t think it will blend Eskom and Solar.

Thanks, think it will be the best to split the DB, with heat pump at an avg of 1.1KWh (does not indicate max load) can I keep it on as essential load, At the moment its runs 2 hours at night and 2 hours in the morning on/off.

[Gerrie]

18 minutes ago, JohanM said:

heat pump at an avg of 1.1KWh (does not indicate max load) can I keep it on as essential load, At the moment its runs 2 hours at night and 2 hours in the morning on/off.

Heat pumps are very energy efficient, I would think you can put the heat pump and pool pump on the inverter and make use of the Solar pv during the day. The stove, tumble drier and dishwasher is the heavy stuff and would be better if kept on grid unless you have a serious battery bank.

 

 

[Bobster.]

41 minutes ago, JohanM said:

Thanks, think it will be the best to split the DB, with heat pump at an avg of 1.1KWh (does not indicate max load) can I keep it on as essential load, At the moment its runs 2 hours at night and 2 hours in the morning on/off.

I run mine on the essential circuits and get away with it. The first run is at 6:15 in the AM when I am not getting much PV and so this runs off the battery.

Circumstances will dictate. When I asked my installer about running the heat pump on the essential loads they said that we could try and we'd have to watch the data from the inverter and see if we got away with it or not. We do get away with it. 

Mine is "on" for about 2 hours in the morning, but the compressor doesn't run all that time. 

There is no yes or no answer here. See earlier advice from @Gerrie: You can try to back up the whole property but depending on what you use and when you may overload the inverter or flatten your batteries too quickly. 

Mine (Goodwe) can draw from the grid for essential loads if the batteries are on the pap side of things and the sun ain't shining. So I have that as a fall back. You need to find out if the Kodak can do that.

[Gerrie]

@JohanM the above solar kit advertise the Pylontech US2000 and I see you mention the US3000. There is quite a price difference between the two, so you should just confirm what size the solar shop is offering you to avoid disappointment.

The Kodak inverter price is very attractive as well but because it is made by  Voltronic it might come with some software bugs as the Axperts are known for software issues. I have nothing against Voltronic I still think it is value for money, I only have a clone Axpert myself that works very well but they do come with software issues and if you don’t find away around it, it can cause headaches. 

[JohanM]

1 minute ago, Gerrie said:

@JohanM the above solar kit advertise the Pylontech US2000 and I see you mention the US3000. There is quite a price difference between the two, so you should just confirm what size the solar shop is offering you to avoid disappointment.

The Kodak inverter price is very attractive as well but because it is made by  Voltronic it might come with some software bugs as the Axperts are known for software issues. I have nothing against Voltronic I still think it is value for money, I only have a clone Axpert myself that works very well but they do come with software issues and if you don’t find away around it, it can cause headaches. 

Thanks for the advice, that kit does comes with the US2000, but I thought I will pay little extra for the US3000C, also the kit only has 6 panels, thinking of adding 2 extra or just upgrade to higher watt panels. 

Still not sure about the inverter, did read about people that are happy with them and other with a lot of issues. Dont have time or patience for working around issues. 

Also my budget for the start is about 65k and trying not to go much higher. 

 

 

 

 

 

[Bobster.]

Here's the data from my system this morning

Green line is SOC, maroon line is the load. You can see my heat pump turning on at 6:15. At that point the water is relatively cool and so the compressor kicks in immediately. Then it turns off about 7:20. For all this time we have no useful PV and you can see the SOC line drops more steeply when the compressor is running.

Later on (after I showered) there is another quick burst from the compressor, looking higher because the kettle was on as well. By that time we have some PV coming in but still draw some juice from the battery. All through this we draw little from the grid. The yellow line going down indicates draw from the grid.

This is the kind of learning you need to go through with your system. I thought I would get away with running the heat pump on the backed up circuits, but the data would tell me if I could or couldn't. I could. There's still some charge left in the battery after that early morning run, and most days PV is about to start coming in.

I don't run the heat pump at night. It turns off for the last time at 3pm but we find the water is still ok for showering up to about 8pm. If I ran it during the night it would take a chunk out of my battery. The battery loses a pretty constant 5% every 2 hours during the night until the heat pump kicks in. Then it loses 14% in one hour. I have 10kw/h of battery, so the percentage loss would be greater for you.

Once the DB is split it's not a big deal for an electrician to move a circuit from the backed up side to the non-backed up side, so you can experiment early on.

[Gerrie]

11 hours ago, JohanM said:

that kit does comes with the US2000, but I thought I will pay little extra for the US3000C

The 2 x US3000’s might enable you to go completely of grid as you only use about 15KWH per day. I am also using about 15 KWH per day and am almost off-grid with 1 x US3000 a second battery will get me completely off grid but I would than also need to add two more panels to make sure the batteries are fully charged in the afternoon. Choosing a inverter is a difficult choice you could also settle for a better inverter and leave one battery for now and add a second battery in a year or two.

[JohanM]

9 minutes ago, Bobster said:

Here's the data from my system this morning

Green line is SOC, maroon line is the load. You can see my heat pump turning on at 6:15. At that point the water is relatively cool and so the compressor kicks in immediately. Then it turns off about 7:20. For all this time we have no useful PV and you can see the SOC line drops more steeply when the compressor is running.

Later on (after I showered) there is another quick burst from the compressor, looking higher because the kettle was on as well. By that time we have some PV coming in but still draw some juice from the battery. All through this we draw little from the grid. The yellow line going down indicates draw from the grid.

This is the kind of learning you need to go through with your system. I thought I would get away with running the heat pump on the backed up circuits, but the data would tell me if I could or couldn't. I could. There's still some charge left in the battery after that early morning run, and most days PV is about to start coming in.

I don't run the heat pump at night. It turns off for the last time at 3pm but we find the water is still ok for showering up to about 8pm. If I ran it during the night it would take a chunk out of my battery. The battery loses a pretty constant 5% every 2 hours during the night until the heat pump kicks in. Then it loses 14% in one hour. I have 10kw/h of battery, so the percentage loss would be greater for you.

Once the DB is split it's not a big deal for an electrician to move a circuit from the backed up side to the non-backed up side, so you can experiment early on.

Thanks, the graph explains allot, I just moved into a house with a heat pump so still learning to get the best out of it, currently its running from 5am to 8am, I need to shower at 6am and the wife at 7am, then again 6pm to 8pm for the kids. Heating up quick but think in winter it will be a deferent story.

Looking to get an electricity usage meter first to test current usage and then make my final decision. 

[JohanM]

18 minutes ago, Gerrie said:

The 2 x US3000’s might enable you to go completely of grid as you only use about 15KWH per day. I am also using about 15 KWH per day and am almost off-grid with 1 x US3000 a second battery will get me completely off grid but I would than also need to add two more panels to make sure the batteries are fully charged in the afternoon. Choosing a inverter is a difficult choice you could also settle for a better inverter and leave one battery for now and add a second battery in a year or two.

Maybe I should stick to the 2 x US2000 that is in the kit and look to upgrade the inverter to a Sunsynk, have read allot of good things here.  

How many panels do you have currently?

[Gerrie]

14 minutes ago, JohanM said:

How many panels do you have currently?

I have 6 x 330W panels and it carries the entire daytime load but the Pylontech charged a bit slower and only reach 100% charge at around 14h00 so a extra battery will mean more charging current required to get two batteries to 100% SOC. 

[Bobster.]

24 minutes ago, JohanM said:

Thanks, the graph explains allot, I just moved into a house with a heat pump so still learning to get the best out of it, currently its running from 5am to 8am, I need to shower at 6am and the wife at 7am, then again 6pm to 8pm for the kids. Heating up quick but think in winter it will be a deferent story.

Looking to get an electricity usage meter first to test current usage and then make my final decision. 

Remember that "on" doesn't mean the compressor is running. Mine is on from 6:15 to 9:00, but the compressor does not run for all of that time.

I just checked data from June last year. Run time in the morning was 10 to 15 minutes longer.

[Tariq]

Hi @JohanM, I have a Sunsynk 5 kW with two Pylontech 2000's and have twelve 355 kW panels, oriented six panels NE and six panels NW, i run a 2 kW geyser, 1.1 kW pool pump, dishwasher, washing machine, tumble dryer, microwave, fridge, freezer,all lights and plugs, obviously not everything at the same time. My night time load with tv,etc runs about 500 watts and drop to about 300 watts when we go to bed, the two batteries last me through the night

     my Eskom buy is 13.7 units for the month so far for the month

[JohanM]

9 minutes ago, Tariq said:

Hi @JohanM, I have a Sunsynk 5 kW with two Pylontech 2000's and have twelve 355 kW panels, oriented six panels NE and six panels NW, i run a 2 kW geyser, 1.1 kW pool pump, dishwasher, washing machine, tumble dryer, microwave, fridge, freezer,all lights and plugs, obviously not everything at the same time. My night time load with tv,etc runs about 500 watts and drop to about 300 watts when we go to bed, the two batteries last me through the night

     my Eskom buy is 13.7 units for the month so far for the month

Wow, this sounds like the setup I need, does the Sunsynk feed back to the grid, like I said I dont want issues with my prepaid meter.

[Tariq]

i have mine set up as zero export and buy in is set at 20 watts , no problems with my prepaid meter tripping

[Bobster.]

3 hours ago, Gerrie said:

The 2 x US3000’s might enable you to go completely of grid as you only use about 15KWH per day. I am also using about 15 KWH per day and am almost off-grid with 1 x US3000 a second battery will get me completely off grid but I would than also need to add two more panels to make sure the batteries are fully charged in the afternoon.

What do you do when there's a run of overcast weather? On bright days I could run my whole house off the grid, but in overcast weather (and we've had a lot in Gauteng lately) I fear I will run out of steam at some point.

[Gerrie]

2 hours ago, Bobster said:

What do you do when there's a run of overcast weather?

I think one quick fix is to set the back to utility battery voltage on most inverters. My inverter works a bit unconventional as I have two automatic change-over switches ( one for alarm, WiFi, lights, cameras etc. and the other for fridges and all other plugs. I can control these C/O switches with my phone. So if I suspect it’s raining at home I can easily switch back to grid. I sometimes check my cameras at home to see if the sun is shining than I just switch back to Solar again. This also works great when I’m away on holiday.

[JaseZA]

I'm very happy with my Kodak VMiii - you need to understand the limitations of it but for the price it's great value for money. The main limitation is that it can't feedback to power non-essential loads like the Sunsynk can. But do the maths - our stove costs us R30 a month in Eskom power vs R10000 extra for Sunsynk inverter = 23 years to pay back! One correction from one of the other comments - on overload (above 5kw for 10 seconds) it won't trip completely, it will switch to grid power if it's available (up to 8kw I think). This is what most newer inverters do. Also, get the 5kw - probably my biggest regret was going 3kw (Didn't have money for extra batteries at the time).

It's definitely not worth having your stove on the inverter - ours can pull upwards of 6kw if we're using the oven and two plates! If you desperately need to cook on battery, use an electric frying pan etc.

I have the same number of panels as that kit and average around 220kwh per month from solar. At 15kwh per day your monthly consumption is 450kwh, so solar is covering about half that. The trick to remember is that you're getting that solar during the day, so you need to have your loads set up to take advantage of that. Average sunny day yield is around 10kwh. 3kwh goes to batteries (around 70% usage of 4.8kwh pack) but then you've got to find 7kwh other consumption during the day. Our dishwasher is around 1kwh per cycle, heat pump 1.1kwh, base load of 300w*8hrs=2.4kwh, pool pump 0.75kwh = 5.25kwh. So you've got to find another 1.75kwh which is probably not too hard. But, what I'm trying to point out it that it might not be worth adding more panels if your goal is to maximize your savings as you probably can't utilize that extra power on sunny days. It will help on cloudy days though and reducing your reliance on Eskom.

Sorry, long response - basically I've done the math probably 10 times and it never makes financial sense for me to go to 8 panels over 6 for our load (which is similar to yours).

[JaseZA]

This was yesterday - a fairly typical day. You can see our batteries where fully charged at 11h45 and because I had no load, I actually lost out on power. It was my fault we had no load - I forgot I'd bypassed the geyser while experimenting the night before and only realized this at 12h20 when the load suddenly increases again. It was hot last night so we ran the aircons quite a bit in the evening so went off battery at 20h45 when it hit 30%. The night before it ran until 05h00 in the morning.

You can see jut after 13h00 we overloaded the 3kw (I think it was kettle boiling?) and the inverter just switched to grid. I do currently have a fault on my inverter where it will sometimes glitch when there is a small overload on battery (around 3.2kw) and it shuts down rather than going to grid. But it happens infrequently enough that I just live with it. Admittedly this is something the Sunsynk doesn't do! If you want good support, Sunsynk (or other more expensive brands) is the way to go.

[JohanM]

13 minutes ago, JaseZA said:

I'm very happy with my Kodak VMiii - you need to understand the limitations of it but for the price it's great value for money. The main limitation is that it can't feedback to power non-essential loads like the Sunsynk can. But do the maths - our stove costs us R30 a month in Eskom power vs R10000 extra for Sunsynk inverter = 23 years to pay back! One correction from one of the other comments - on overload (above 5kw for 10 seconds) it won't trip completely, it will switch to grid power if it's available (up to 8kw I think). This is what most newer inverters do. Also, get the 5kw - probably my biggest regret was going 3kw (Didn't have money for extra batteries at the time).

It's definitely not worth having your stove on the inverter - ours can pull upwards of 6kw if we're using the oven and two plates! If you desperately need to cook on battery, use an electric frying pan etc.

I have the same number of panels as that kit and average around 220kwh per month from solar. At 15kwh per day your monthly consumption is 450kwh, so solar is covering about half that. The trick to remember is that you're getting that solar during the day, so you need to have your loads set up to take advantage of that. Average sunny day yield is around 10kwh. 3kwh goes to batteries (around 70% usage of 4.8kwh pack) but then you've got to find 7kwh other consumption during the day. Our dishwasher is around 1kwh per cycle, heat pump 1.1kwh, base load of 300w*8hrs=2.4kwh, pool pump 0.75kwh = 5.25kwh. So you've got to find another 1.75kwh which is probably not too hard. But, what I'm trying to point out it that it might not be worth adding more panels if your goal is to maximize your savings as you probably can't utilize that extra power on sunny days. It will help on cloudy days though and reducing your reliance on Eskom.

Sorry, long response - basically I've done the math probably 10 times and it never makes financial sense for me to go to 8 panels over 6 for our load (which is similar to yours).

Thanks JaseZa, you make a couple of good points.

I replaced the stove with gas last week, so that will also help, only using the oven now and then.

Going to buy an electricity usage meter and analyze my usage during the day, I think it will make the decision easier.

Still little torn between the kodak and Sunsynk, sure kodak will be 100% for now but maybe the Sunsynk will be better for future upgrades.

Appreciate the writeup.