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Tesla PW, 6Kw inverter and 8kwP panel - being charged for excess grid feed


Germann U. Boeingg
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Good morning all, 

We have the above configuration, but the installer seems unable to overcome the issue that for any excess production (i.e. when the battery is fully charged), we are being charged by the municipality (the prepaid meter simply runs backwards). A current meter was installed to stop production when battery is fully charged, no success. Here the question, to find out if my expectations are incorrect:

With a grid tied system, and a battery, priority should be to fill the battery, then feed the house consumption and dispose the surplus onto the grid, in our case without getting rewarded for it, correct? Do we have to apply to the municipality to be allowed to feed in (i.e. get paid for it), as per the installer this costs about R12K for the installation and a monthly fee - i.e. we'd rather "lose" overproduction. 

Has anyone got experience with setup options for Tesla PW, in combination with a Goodwe 6kw converter and a municipal prepaid meter connection? 

Thanks  best regards

Thanks 

 

 

 

tesla PW.PNG

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In all the cases that I know of, when feeding into the grid, the prepaid meter actually clocks forwards , not backwards. I am aware of the ancient "spinning disk" meters in CoCT that actually run backwards (decreasing usage), but not prepaid meters. I guess that what you are saying is that the meter is actually clocking it up as usage?

I will leave your questions about billing and rebates to someone familiar with CoCT practices, perhaps @Erastus can assist?

 

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11 hours ago, YellowTapemeasure said:

In all the cases that I know of, when feeding into the grid, the prepaid meter actually clocks forwards , not backwards. I am aware of the ancient "spinning disk" meters in CoCT that actually run backwards (decreasing usage), but not prepaid meters. I guess that what you are saying is that the meter is actually clocking it up as usage?

I will leave your questions about billing and rebates to someone familiar with CoCT practices, perhaps @Erastus can assist?

 

Sorry, wasn't clear - yes prepaid metre clocking feed as usage i.e. decreasing the units available. thank you! 

 

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23 minutes ago, Germann U. Boeingg said:

Sorry, wasn't clear - yes prepaid metre clocking feed as usage i.e. decreasing the units available. thank you! 

 

I'm not familiar with the system but most if not all hybrid or grid tied inverters has a setting to select zero export. There would be a CT sensor on the main grid line to detect this and stop the inverter from back feeding into the grid.

Can you perhaps share some of your settings screens?

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On the prepaid meter. You need to apply to CoCT for a bidirectional prepaid meter. All normal prepaid meters will either trip or run the units down when feeding into the grid. You cannot feed in with a normal prepaid meter.

CoCT does charge R12K for the bidirectional meter. I would suggest to just set the system to zero export after batteries are full and loads are met. Unless you really want excess to feed into the grid then you will need to buy the bidirectional prepaid meter from CoCT for R12k.

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What ever you do do go grid tie and push back. Its more than worth it.

I been involved with prepaid systems and meter for a few years.  No prepaid meter is designed to increase when you feed back.  They are "dumb" devices that replaces the wheel type meter and manages people so they pay. It therefore does not have the ability to measure direction its not part of the specs.

In time it might change as more SSEG generate to little and then do not pay ....

The meter COCT has "standardized" on is a Landys & Gyrr.  If you now this manufacturer they lead where others follow. Thus they install a 3 phase meter even if they only use a single phase makes upgrade easier should you want to go to 3 phase and push more back.

I must admit been through a few arguments and the reasons for selection 3phase and Land & Gyrr makes 100% sense.  Might be a lot to install but this meter simply works.  But then  I had 2 out of the box failures a very very very very very seldom occurrence.

The new meter takes 15min data 4 per hour and works well.
 

Yes 12K is a lot but totaly worth it and to feed back beats any battery system hands down.

You can not recover your battery costs and it will always cost money.

Feed back you get back.  It is more than a tax free income.

 

  1. You take $ away from those that steel from us.
  2. Certain jobs will become less and could add to saving in the future
  3. If you are "thinking on pollution" its a good product as the pollution stays in China
  4. Once you feed back you understand how one wastes with batteries.

My opinion any person chooses to go batteries rather than grid tie need some help. O know there are some good points on batteries but very few.

Below is what you see on the COCT system when you feed back.  These graphs represent +/- R550 cash back.  System cost < R45 000.

image.thumb.png.f16ea4117e44349e04f9d5fd065745e8.png

 

 

 

Edited by Erastus
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44 minutes ago, Erastus said:

What ever you do do go grid tie and push back. Its more than worth it.

I been involved with prepaid systems and meter for a few years.  No prepaid meter is designed to increase when you feed back.  They are "dumb" devices that replaces the wheel type meter and manages people so they pay. It therefore does not have the ability to measure direction its not part of the specs.

In time it might change as more SSEG generate to little and then do not pay ....

The meter COCT has "standardized" on is a Landys & Gyrr.  If you now this manufacturer they lead where others follow. Thus they install a 3 phase meter even if they only use a single phase makes upgrade easier should you want to go to 3 phase and push more back.

I must admit been through a few arguments and the reasons for selection 3phase and Land & Gyrr makes 100% sense.  Might be a lot to install but this meter simply works.  But then  I had 2 out of the box failures a very very very very very seldom occurrence.

The new meter takes 15min data 4 per hour and works well.
 

Yes 12K is a lot but totaly worth it and to feed back beats any battery system hands down.

You can not recover your battery costs and it will always cost money.

Feed back you get back.  It is more than a tax free income.

 

  1. You take $ away from those that steel from us.
  2. Certain jobs will become less and could add to saving in the future
  3. If you are "thinking on pollution" its a good product as the pollution stays in China
  4. Once you feed back you understand how one wastes with batteries.

My opinion any person chooses to go batteries rather than grid tie need some help. O know there are some good points on batteries but very few.

Below is what you see on the COCT system when you feed back.  These graphs represent +/- R550 cash back.  System cost < R45 000.

image.thumb.png.f16ea4117e44349e04f9d5fd065745e8.png

 

 

 

Which specific Landis Gyr meter are you speaking about? Model number?

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52 minutes ago, Erastus said:

What ever you do do go grid tie and push back. Its more than worth it.

I been involved with prepaid systems and meter for a few years.  No prepaid meter is designed to increase when you feed back.  They are "dumb" devices that replaces the wheel type meter and manages people so they pay. It therefore does not have the ability to measure direction its not part of the specs.

In time it might change as more SSEG generate to little and then do not pay ....

The meter COCT has "standardized" on is a Landys & Gyrr.  If you now this manufacturer they lead where others follow. Thus they install a 3 phase meter even if they only use a single phase makes upgrade easier should you want to go to 3 phase and push more back.

I must admit been through a few arguments and the reasons for selection 3phase and Land & Gyrr makes 100% sense.  Might be a lot to install but this meter simply works.  But then  I had 2 out of the box failures a very very very very very seldom occurrence.

The new meter takes 15min data 4 per hour and works well.
 

Yes 12K is a lot but totaly worth it and to feed back beats any battery system hands down.

You can not recover your battery costs and it will always cost money.

Feed back you get back.  It is more than a tax free income.

 

  1. You take $ away from those that steel from us.
  2. Certain jobs will become less and could add to saving in the future
  3. If you are "thinking on pollution" its a good product as the pollution stays in China
  4. Once you feed back you understand how one wastes with batteries.

My opinion any person chooses to go batteries rather than grid tie need some help. O know there are some good points on batteries but very few.

Below is what you see on the COCT system when you feed back.  These graphs represent +/- R550 cash back.  System cost < R45 000.

image.thumb.png.f16ea4117e44349e04f9d5fd065745e8.png

 

 

 

Hi Erastus, 

Thank you for the detailed response. For our specific user case, batterie expense made a lot of sense and still does. 

However, feeding back and getting "tax free income" for it only works to a certain point correct, as you have to remain a net user (i.e. won't get paid for exccess you feed into the grid)? As we produce 90% of our use ourselves, we require very little from the grid. So does it really make sense to get paid for the remaining 10% before we are not a net consumer anymore, or do we get paid for evry single KW we produce and feed back, no matter how much we consume from the grid? 

Thanks  

 

 

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2 hours ago, Germann U. Boeingg said:

Hi Erastus, 

Thank you for the detailed response. For our specific user case, batterie expense made a lot of sense and still does. 

However, feeding back and getting "tax free income" for it only works to a certain point correct, as you have to remain a net user (i.e. won't get paid for exccess you feed into the grid)? As we produce 90% of our use ourselves, we require very little from the grid. So does it really make sense to get paid for the remaining 10% before we are not a net consumer anymore, or do we get paid for evry single KW we produce and feed back, no matter how much we consume from the grid? 

Thanks  

 

 

Date     

 

Import Kwh Export Kwh Kw HrDiff Actual Cost R Val
Aug 2019 535.080 15.200 519.88 R 973.04 R 973.04
Sep 2019 657.510 0.00 1,177.39 R 1,238.79 R 2,211.83
Oct 2019 795.690 0.00 1,973.08 R 1,563.65 R 3,775.47
Nov 2019 764.070 0.00 2,737.15 R 1,489.31 R 5,264.78
Dec 2019 800.700 0.00 3,537.85 R 1,575.43 R 6,840.21
Jan 2020 825.680 0.00 4,363.53 R 1,634.15 R 8,474.36
Feb 2020 743.810 0.00 5,107.34 R 1,441.68 R 9,916.04
March 2020 637.010 21.78 5,722.57 R 1,190.59 R 11,106.63
April 2020 505.720 39.06 6,189.23 R 1,074.97 R 12,181.60
May 2020 543.980 26.84 6,706.37 R 980.88 R 13,162.49
June 2020 608.070 18.15 7,296.29 R 1,109.26 R 14,271.75
Jul 2020 752.540 50.67 7,998.16 R 1,425.09 R 15,696.84
Aug 2020 706.460 176.51 8,528.11 R 1,224.59 R 16,921.43
Sep 2020 620.880 271.35 8,877.64 R 943.27 R 17,864.70
Oct 2020 457.383 604.14 8,730.88 R 398.79 R 18,263.50
Nov 2020 385.606 844.05 8,272.44 R 91.06 R 18,354.56
Dec 2020 378.760 1,105.29 7,545.91 R-112.75 R 18,241.81
JAN 2021 326.920 1,530.12 6,342.71 R-519.20 R 17,722.60
Edited by Erastus
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42 minutes ago, Brani said:

Agreed,

so you have to pay 12K for the meter, pay monthly cost of R12.36/day and still be a net consumer of electricity. I would think that even after you have paid for the battery, which caters for ever so present load shedding situation, i would spend that 12k on more panels or more batteries in order to get closer to being off-grid.

 

 

image.png.ea2adff883700e59fe6ff5cad5d1b51b.png

With all due respect.

My inverter Cost me                    R13000
My PV I bought 8 second hand  R   8000
My Other PV's                             R 22000
Meter                                           R  11000

I did the installation.  Thus far instead of paying the council I saved +/- R 9000 that I did not have to pay the council.  I got back R 630.  Meter paid

Thus  R43K to go and my solar is paid.  I had batteries and all that stuff DO NOT sit in the dark but did not pay for a battery.

As a fact my batt back up cost is R 750 and MY HOUSE IS LIT.  Another R980  DSTV and TV will work but who cares about TV a laptop lasts longer than 2 hours.

All you have to do is to think out of the box.  You take at least 3 years to get your ROI on the batt then you have +/- 1 year left then it starts all over again.

 

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12 minutes ago, Brani said:

Hi Erastus,

I assume your last column is 2 months behind due to them having to calculate and give you credit?

My worry is that in the info sheet attached they state that you have to be a net customer over a 12 month period, and by October 2021 you will be well into an exporter.

Does anyone have experience with this over longer period of time?

 

What happens to the negative amount? Deducted from your total municipal account?

 

 

PV info sheet on tariffs_final.pdf 637.89 kB · 0 downloads

No my last 2 columns is what the City should charge and then what they charge.  They totally over charged us with electricity. I have thus far  helped a few people busy with a data base as I do not want to do manual calculations.  The red R6K is what they incorrectly charged in a very sly manner.. Currently I have a query on it as they are robbing us.  More about that at a later stage. In short the database will take SAP info, solar info do all the calculations as well as prepaid and account meter data.

The council refused to give me raw meter data as my Kwhr did not match the "billing" took months to get it and it was blatantly refused until I took action and it stopped just before the lawyers got involved.  They then gave me the data I did a recon and saw they robbed me with R6K in 13 months.  They do it very sly way and only because of a faulty meter I saw what they are doing very clever way of doing it but will give more info once they respond on my claims

I was on batteries for 2 or 3 years. Been there not impressed as to the ROI. 

Edited by Erastus
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5 hours ago, Brani said:

This is the point I was trying to make. The conditions are not favorable for SSEG anywhere in South Africa. I am in Ekurhuleni, and if I want to feed back, I have to pay for the change of meter and get ZERO for feeding back. Best option, as per Achmat, zero feedback and store excess energy in batteries. 

Considering load shedding, unreliable supply, municipal account complications and all those factors, we cannot think outside of the box.

 

The contract state they pay out. The laws are busy changing. So they will pay out.  Achmat does not have the best option unless he sells batteries.

There is no absolute no way that the ROI is good on a battery. 
I had batteries for 3 years. I designed my own charging systems and monitoring systems. It cost < R1800.
I buy batteries at whole sale as we use plenty in our business.
Let me explain 48V 100A  R12500 depending the R/$ and that is Lipoe ....

In spite of this the ROI is not worth it.

Thinking out of the box I mean to get power when Eksdom is load  shedding . Even then R12500 is to expensive.

My lights backup costs R590 if you want exact cost.  5 hours standby time

That's what I meant with think out of the box

Let me try and explain again.

Column actual cost is what they should have charged.  
Column R val is what they charged. What they charged is R6K more.
Or simply put what they stole from me and busy stealing from others.

Hope this clears it.

Bear in mind I have :
a 55 000l koi pond,
water cleaning system,
16000l pool.
I water my garden from well point.
Same water I use for my house.
an electric geyser combo
I have 2 PC running 24/7.
This is this months data.

Yesterday I used 7.942 Kw that is from the L & G meter NOT mine

R Flux       Import Kwhr      Export Kwhr      R Import      R Export      Nett R X.xx         R Total Follow The Sun
76.400 21.239 13.129 -55.161 R 24.15 R-40.39 R-16.25 R-16.25 42.032
77.590 19.345 11.950 -58.245 R 21.98 R-42.65 R-20.67 R-36.92 46.295
70.700 23.383 14.248 -47.317 R 26.21 R-34.65 R-8.44 R-45.36 33.069
67.600 21.010 8.620 -46.590 R 15.85 R-34.12 R-18.26 R-63.63 37.970
69.500 22.337 11.242 -47.163 R 20.68 R-34.54 R-13.86 R-77.49 35.921
76.400 21.706 12.629 -54.694 R 23.23 R-40.05 R-16.82 R-94.31 42.065
74.500 23.396 10.620 -51.104 R 19.53 R-37.42 R-17.89 R-112.20 40.484
75.500 22.654 9.964 -52.846 R 18.33 R-38.70 R-20.37 R-132.57 42.882
71.900 18.685 9.391 -53.215 R 17.27 R-38.97 R-21.70 R-154.27 43.824
76.000 28.862 12.382 -47.138 R 22.77 R-34.52 R-11.74 R-166.01 34.756
73.800 22.301 8.782 -51.499 R 16.15 R-37.71 R-21.56 R-187.57 42.717
70.800 21.110 8.611 -49.690 R 15.84 R-36.39 R-20.55 R-208.12 41.079
69.800 18.944 10.134 -50.856 R 18.64 R-37.24 R-18.60 R-226.73 40.722
70.400 21.597 11.432 -48.803 R 21.03 R-35.74 R-14.71 R-241.44 37.371
45.000 14.698 12.732 -30.302 R 23.42 R-22.19 R 1.23 R-240.21 17.570
40.100 14.233 10.575 -25.867 R 19.45 R-18.94 R 0.51 R-239.70 15.292
75.600 19.813 9.910 -55.787 R 18.23 R-40.85 R-22.63 R-262.33 45.877
74.000 20.569 7.936 -53.431 R 14.60 R-39.13 R-24.53 R-286.86 45.495
75.000 19.883 8.705 -55.117 R 16.01 R-40.36 R-24.35 R-311.21 46.412
76.600 24.252 7.924 -52.348 R 14.57 R-38.33 R-23.76 R-334.97 44.424
47.000 47.000 0.000 0.000 R 0.00 R 0.00 R 0.00 R-334.97 0.000
0.000 0.000 0.000 0.000 R 0.00 R 0.00 R 0.00 R-334.97 0.000
0.000 0.000 0.000 0.000 R 0.00 R 0.00 R 0.00 R-334.97 0.000
0.000 0.000 0.000 0.000 R 0.00 R 0.00 R 0.00 R-334.97 0.000
0.000 0.000 0.000 0.000 R 0.00 R 0.00 R 0.00 R-334.97 0.000
0.000 0.000 0.000 0.000 R 0.00 R 0.00 R 0.00 R-334.97 0.000
0.000 0.000 0.000 0.000 R 0.00 R 0.00 R 0.00 R-334.97 0.000
0.000 0.000 0.000 0.000 R 0.00 R 0.00 R 0.00 R-334.97 0.000
0.000 0.000 0.000 0.000 R 0.00 R 0.00 R 0.00 R-334.97 0.000
0.000 0.000 0.000 0.000 R 0.00 R 0.00 R 0.00 R-334.97 0.000
0.000 0.000 0.000 0.000 R 0.00 R 0.00 R 0.00 R-334.97 0.000
1,454.190 496.000 210.916 -987.173 R 387.94 R-722.91 R-334.97   776.257
               
               
               
               
 

 

 

           
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
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Just got my latest bill:

Consumption charge: Residential SSEG
& (1) 403.3780 kWh @ R 1.8393                                     741.93
Generation Offset    ( 1523.860 kWh X R 0.7324 )       1116.08-

Got 1116.08 Back

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1 hour ago, Brani said:

Just proving my point.

Your CoCT balance is R741.93 +service charge of R12.36*30 (R370.80) -R1116.08 = -R3.35

You would have been better of going off grid with batteries.

Lets look at CoCT - they scored 1120.48KWh from you, basically leaving you with zero account, and sold that at R1.83 or more to your next door neighbor. Happy bunch! Not to mention that they will cap you off after 12 months of you becoming net exporter. If they don't, I'm happy for you.

On average, you produce about 50KWh surplus on top of what you use during the day, and consume about 13.5KWh at night. You could have stored about 15KWh and that leaves you with 35KWh extra.

If you chose to go battery route, you could have saved (conservatively) 12 panels at R3000 = R36000. Add the meter of R11000. 

Buy a battery system for R90000 - R47000 = R43000 in red. 

This will save your R741.93 per month (service charge excluded), and payback would be 58 months, let's say 5 years. Full backup during load shedding. No nonsense with municipality. That sounds like a good deal to me.

 

Busy with 2 maybe three 4Kw wind turbines. 
Then I am waiting for the council to finish my plans then the real system will have an additional 160 540W panels with 3 phase 10Kw inverters.

I understand the batteries. I am putting my koi pond on batteries and I am putting the lights, TV's, decoders and lights on batteries.
Will share it later first the turbines and the wait for the council.  Thanks for your sharing.
This is what you are saying:

                       
    No Batteries         Batteries        
    210.916 987.173 0              
    215.400 -1,014.730       0.000 -1,014.730      
  10.77 118.470 -558.102 -50.74   0.00 0.000 -558.102 -50.74    
    333.870 -1,572.832 0     0.000 -1,572.832 0    
      0         0 0    
        0              
    import export 31     import export 31    
    333.87 -1572.83 20     0.000 -1,572.832 20    
  Markup % Kwh Usage -1,238.962 11     Kwh Usage 1,572.832 11    
  251.17 R 1.84 R 0.73       R 1.84 R 0.73      
    R 614.09 R-1,151.78       R 0.00 R-1,151.78      
  R 244.49 356.1 R-537.70       356.1 R 1,151.78      
    R 1.46 R 488.99 R 1,640.77     R 1.46 R 0.00 R 1,151.78    
    R 0.73 R 244.49 R 1,396.28     R 0.73 R 0.00 R 1,151.78    
      R-585.35                
    Cost R-537.70 R-907.29     Cost R 1,151.78      
                       
                       
      R 614.09                
                       
Edited by Erastus
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Good morning all, thanks for the debate & point. 

Yes, as it stands we have a Tesla battery (14.5kw usable supply). The question was indeed if you have to remain a net consumer of grid electricity or if you only get paid equally to what you actually buy, no matter how much you produce. It certainly seems that their is uncertainty about that, which makes it impossible to calculate possible returns of forking out 12K for a meter and a daily service charge. My grid consumption a the moment is only about R200 per month, so if you need to remain a net consumer (to be confirmed) indeed, there's no point to feed surplus into the grid 

We have now moved the entire house, including geyser and pool pump, to be fed of the battery at all times, and disconnect from the grid until the CT meter limits export correctly. From my point of view there is no point feeding into the grid. There is also a comfort gain, as we now run aircons much more (and happily so) than before. Have you ever used the self cleaning function of your oven and not feel guilty about it :-)? 

In summary, thanks for all your input - it seems that everyone has got a different angle from simply saving to surviving load shedding to gaining comfort levels - and everyone must decide for themselves, which one takes priority. I am a mix of the three.

Have a great day!

Anyone interested in a Bargain: Solarworld Sunplug eco TL1 3.6kw Grid inverter ? https://www.gumtree.co.za/a-generators-solar-power/tamboerskloof/bargain-solarworld-sunplug-eco-tl1-3-6kw-grid-inverter/1007933270510910259157009

Edited by Germann U. Boeingg
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1 minute ago, Brani said:

Did you manage to find a correct setting for your tesla? Maybe share some settings screens for us?

Waiting for batteries to reach 100% - Tesla is fine, the Goodwe inverter & CT are the settings we needed changed, so we will know more once batteries are full. -)

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57 minutes ago, Germann U. Boeingg said:

Good morning all, thanks for the debate & point. 

Yes, as it stands we have a Tesla battery (14.5kw usable supply). The question was indeed if you have to remain a net consumer of grid electricity or if you only get paid equally to what you actually buy, no matter how much you produce. It certainly seems that their is uncertainty about that, which makes it impossible to calculate possible returns of forking out 12K for a meter and a daily service charge. My grid consumption a the moment is only about R200 per month, so if you need to remain a net consumer (to be confirmed) indeed, there's no point to feed surplus into the grid 

We have now moved the entire house, including geyser and pool pump, to be fed of the battery at all times, and disconnect from the grid until the CT meter limits export correctly. From my point of view there is no point feeding into the grid. There is also a comfort gain, as we now run aircons much more (and happily so) than before. Have you ever used the self cleaning function of your oven and not feel guilty about it :-)? 

In summary, thanks for all your input - it seems that everyone has got a different angle from simply saving to surviving load shedding to gaining comfort levels - and everyone must decide for themselves, which one takes priority. I am a mix of the three.

Have a great day!

Anyone interested in a Bargain: Solarworld Sunplug eco TL1 3.6kw Grid inverter ? https://www.gumtree.co.za/a-generators-solar-power/tamboerskloof/bargain-solarworld-sunplug-eco-tl1-3-6kw-grid-inverter/1007933270510910259157009

Can you share the manual of this inverter please. 

Might be interested but only at the end of Feb. 

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