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No changes in KWh per day


Nadeem Ahmed
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I have recently installed Infini V 5KW inverter at my house.  It runs all of my household lights, fans, 2 referigerators, 1 inverter based air conditioner.  A microwave and an iron is also on it but they are occasionally used for short periods.  There is a second inverter based air conditioner which I have not connected to this inverter yet.  I have 3-phase grid supply available.Throughout the day, the load varies anywhere from 600W to 2500W.  I am using SUB and off-grid modes.

I have 3 strings of 325W x 3 Renesola solar panels (9 panels) connected at PV1 input of this system.  At peak sunny days, I have noticed these panels going up to providing 2KW of power (as shown on the inverter LCD).

I was expecting to get some electricity saving each month but I was surprised to notice that I got almost the same amounts of KWh units consumed as last month.  Then I started taking readings from my grid meter on daily basis.  My daily consumption was between 36-41 units per 24 hours.  I then kept my inverter switched off for 24 hours and put its load directly on grid.  After 24 hours, I had the same consumption of electricity i.e. 38KWh.

This is not what I was expecting.  What could I be doing wrong?  Any suggestions from the group?

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Solar production is based on loads. You have nearly 3kW of panels  but if on a sunny day you are using 400W of power the panels will only produce 400W of power. You mention using SUB and off-grid modes - I presume you have batteries.

I have a very similar setup and I produce about 12 kWh in winter and  up to 20 kWh in summer. I am totally off-grid so charging my batteries counts as a load and we are producing  2.4kW. To get the most out of your solar you need sustained loads. I even have a water heater with a 1500W element to provide a dump load if we not cooking etc.

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54 minutes ago, Chris Hobson said:

Solar production is based on loads. You have nearly 3kW of panels  but if on a sunny day you are using 400W of power the panels will only produce 400W of power. You mention using SUB and off-grid modes - I presume you have batteries.

Yes I have 4 x 150AH Deep Cycle Lead Acid Batteries.

Looking at bar graphs from SolarPower application, the maximum production I got in one day was 14.38KWh.  Do you have the same amount of panels or more?

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1 hour ago, Chris Hobson said:

I have a very similar setup and I produce about 12 kWh in winter and  up to 20 kWh in summer. I am totally off-grid so charging my batteries counts as a load and we are producing  2.4kW. To get the most out of your solar you need sustained loads. I even have a water heater with a 1500W element to provide a dump load if we not cooking etc.

I have also noticed that even though PV panels are capable of producing a certain amount of power but the inverter does not consume that all and instead takes some portion of it from grid which causes unnecessary load on grid while the PV power is not utilized to full extent.  Is this observation right?  What is the remedy?

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9 minutes ago, Nadeem Ahmed said:

  Do you have the same amount of panels or more?

I have 3 kW of panels. Depending what your goals with the batteries are will determine how you use them.  If you are saving them for a power failure  all well and good but then you are going to have to be creative in managing your loads. If you plan to use your batteries then SBU would be better than SUB. The advantage of batteries it you have a load that initially can accept quite a high current and it is variable in nature and so matches your solar production.

 

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19 minutes ago, Nadeem Ahmed said:

I have also noticed that even though PV panels are capable of producing a certain amount of power but the inverter does not consume that all and instead takes some portion of it from grid which causes unnecessary load on grid while the PV power is not utilized to full extent.  Is this observation right?  What is the remedy?

Probably to do with your settings. Is this a V I or a V II?

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Stupid question. The infinisolar can be grid tied. Make sure you are not pushing electricity into the grid. If you do not have a Bi-directional meter installed your meter will measure units both ways. I had the problem with my first grid-tied setup. I was providing Eskom with electricity and paying them for it at the same time:wacko: Make sure you have Zero feedback and check your usage again......

With zero feedback your panels will only generate electricity to cover your load, inverter idle consumption, etc. With feedback it will generate maximum possible and feed it back into the grid and your meter (only if bi-directional) will run backwards while doing so. Only when usage exceeds generation will it start using units again.....

Anyone who can explain it better? it's all in my head but cannot seem to get it out properly.:D

Edited by Czauto
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2 hours ago, Czauto said:

If you do not have a Bi-directional meter installed your meter will measure units both ways.

Depends on which one.

Was told by a Sparkie that if the older wheel meters turn back, that they are actually faulty.

The cost for a bi-directional meter, is like R8k ... and a fee per day. They can go and jump.

Go for self consumption, do it right, before it is noticed by your local supplier.

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Exactly. That's why i sold my grid tie inverter. I'd have to generate at least 300kwh/month just to break even with the monthly fees, nevermind the initial cost of the meter. 

But if the infinisolar is setup to feedback through the wrong meter it would explain why he's not saving by generating electricity but rather oaying for every kwh that's being fed back to the grid.... Don't know the infinisolar v that well but as i understand it has to be calibrated for zero feedback. Am i right? I was actually looking at a infinisolar 4kw super to replace my axpert but decided to save for the blue stuff instead. 

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5 minutes ago, Czauto said:

... feedback through the wrong meter it would explain why he's not saving by generating electricity but rather paying for every kwh that's being fed back to the grid....

AHA!!! I missed that. Most definitely a possible problem.

5 minutes ago, Czauto said:

That's why i sold my grid tie inverter.

And I am going grid tied ... Self Consumption the key on a PAYG meter.

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3 hours ago, Czauto said:

Stupid question. The infinisolar can be grid tied. Make sure you are not pushing electricity into the grid. If you do not have a Bi-directional meter installed your meter will measure units both ways. I had the problem with my first grid-tied setup. I was providing Eskom with electricity and paying them for it at the same time:wacko: Make sure you have Zero feedback and check your usage again......

With zero feedback your panels will only generate electricity to cover your load, inverter idle consumption, etc. With feedback it will generate maximum possible and feed it back into the grid and your meter (only if bi-directional) will run backwards while doing so. Only when usage exceeds generation will it start using units again.....

Anyone who can explain it better? it's all in my head but cannot seem to get it out properly.:D

I am not feeding back to grid.  Setting 09 is set to GFD. I knew it already but I double-checked it again.

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1 hour ago, The Terrible Triplett said:

Was told by a Sparkie that if the older wheel meters turn back, that they are actually faulty.

Some have reverse lockup and won't turn back (although you can still push the energy in if you want to, which is often easier to do than mess with a limiter). The really old ones turn backwards.

18 minutes ago, Nadeem Ahmed said:

It is a digital meter though

Most meters don't sense the power direction, just how much is passing, and it bills the same in both directions.

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12 hours ago, plonkster said:

Some have reverse lockup and won't turn back (although you can still push the energy in if you want to, which is often easier to do than mess with a limiter). The really old ones turn backwards.

Most meters don't sense the power direction, just how much is passing, and it bills the same in both directions.

Isn't the attached setting showing that the inverter is in off-grid mode (I have GfD set in my case, which refers to feed to grid disabled)?  What else I need to check?

InverterSetting.jpg

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Your problem is almost similar to mine.

What I have figured out so far is that when inverter starts to mix grid supply with either PV or battery, it does something strange to the grid supply that reduces the power factor at the inverter AC input significantly (<=0.5).  I have got to know this as I have 2 energy meters installed both at inverter AC input and output.  They measure Volts, Amps, Watts and KWh.  I have attached a picture of those energy meters.  The left one in the picture measures the AC input.  Check the PF on both left and right meters and see the difference.  At night, when PV stops working, the power factor gets normal (>=0.9).  If you don't know how to calculate ... you can do it by dividing the real power (Watts) by apparent power (volts x amps).

Can somebody on this forum shed some more light on to this?

20180916.jpg

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On 2018/09/16 at 10:48 AM, Nadeem Ahmed said:

Your problem is almost similar to mine.

What I have figured out so far is that when inverter starts to mix grid supply with either PV or battery, it does something strange to the grid supply that reduces the power factor at the inverter AC input significantly (<=0.5).  I have got to know this as I have 2 energy meters installed both at inverter AC input and output.  They measure Volts, Amps, Watts and KWh.  I have attached a picture of those energy meters.  The left one in the picture measures the AC input.  Check the PF on both left and right meters and see the difference.  At night, when PV stops working, the power factor gets normal (>=0.9).  If you don't know how to calculate ... you can do it by dividing the real power (Watts) by apparent power (volts x amps).

Can somebody on this forum shed some more light on to this?

20180916.jpg

On another thread, @plonkster gave very valuable information for my problem ... Thank you plonkster.

I have 3-phase grid supply at my house where I am running Infini V 5kw on one of these phases.  I have put all my inverter based load on this single phase whereas some of the other load is running on the other 2 phases.

I am unable to fully understand full application of "output model" inverter setting as shown in attached picture.  Will you please guide me which I option should I use in this scenario?

Thank you in advance.

Settings.jpg

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If you have just one inverter in you setup, the "single" is the right choice.

Other choices are there to combine 2 or more inverters into a strong 1-phase system (parallel) or into a 3-phase system where each phase is being serviced by it's own dedicated inverter(R-S-T).

 

Btw - source priority on the right side indicates, that you're not using the batteries for powering the loads. Looks like you're running from the grid over the night. Can you doublecheck that?

 

I'm using infinisolar too, but a different model so my settings screen looks very different from yours...

Youda

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35 minutes ago, Nadeem Ahmed said:

I have 3-phase grid supply at my house where I am running Infini V 5kw on one of these phases.  I have put all my inverter based load on this single phase whereas some of the other load is running on the other 2 phases. 

I am unable to fully understand full application of "output model" inverter setting as shown in attached picture.  Will you please guide me which I option should I use in this scenario? 

I can't help you directly with that, but I can give more background info.

A three-phase meter will usually bill you for the total over the three phases. So even if you have a inverter installed on one phase, you might still pay for power used on the other two. That is unless you have a three-phase unit.

Where you have inverters on more than one phase, or a three-phase unit, you can sometimes choose whether you want the phases to be zeroed individually, or if you want the total to be zeroed.

By way of example, if I have 3 x 3KVA inverters on all three phases, and a 5KVA load on one phase with 500W loads on the other two: In this scenario my total load is 6KW, and I have 9KW worth of inverters installed. I can obtain an overall zero by pushing 3KVA on the first phase and 1.5KVA each on the other two, in other words, I make up for the 2kw shortfall on L1 by feeding 1KW into L2 and L3 respectively.

If I however attempt to zero them individually, then it isn't possible. I can push 3kva on L1 (and have 2kw left over), while L2 and L3 each get 500W to get them to their individual zero points.

With Victron inverters you can be even more sneaky: You can install an inverter on L1, and if there are loads on L2 and L3 it can compensate for them by feeding into L1, thereby zeroing all three phases with only one inverter.

So now the question becomes whether this is possible with your unit, what those items in the drop-down mean, and if the consumption on the other two phases might account for the fact that you're seeing little or no change in consumption.

Edited by plonkster
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