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Sunsynk 8kw with Generator Question


Sc00bs
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Hi Guys, I have a question regarding the functioning of my Sunsynk 8kw inverter with my 5.5kw petrol generator. 

The Inverter is connected to a Eskom/Generator change over switch that I can use to select my source power.

If I switch from Eskom to Generator, the AC light on the inverter lights up but I cannot get any power from the generator.

If have a look on my laptop the inverter is not seeing any grid frequency, it obviously sees 50hz when running on Eskom power.

If I bypass the inverter totally I can run my house from the generator directly, I would however prefer to be able to charge up my batteries using my generator which I currently cannot do.

I was thinking that the power from the generator is perhaps not living up to what the inverter is expecting for some reason. 

Any idea what could be causing the problem? 

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Basically your inverter sees the AC from the generator between never switches off the anti islanding mode.

And hence as you state, it does not accept any charge from the generator to charge the batteries.

I also experienced the same and was wondering if it could have anything do to with the fact that the generator is not earthed. 

My generator is mobile so typically, there is no permanent earth linked up but I have not tested it with a earth connection.

However, it may be something totally different...

Also looking for the answer on this questions

 

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4 hours ago, YellowTapemeasure said:

Frequency is important, as is expected voltage. The Sunsynk has a page where the tolerance for this can be adjusted. Best to measure what your genny is producing and adjust the Sunsynk accordingly, see

 

Thanks @YellowTapemeasure

Seems he did not report back on the matter.

However, that same grid screen says grid reconnect time = 60 seconds and power factor of 1.0

Could it be that the power factor of the genny is less than 1.0?

It does seems strange that in that thread that it sees the AC volts but 0 for frequency?

(this article seems to suggest that single phase gennies below 40 kw run at a PF of 1 - https://www.generatorsource.com/Industrial_Generator_Phases_and_Voltage.aspx )

 

 

 

 

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Ok, gen frequency is 49.8hz which falls well within the min/max settings in the grid menu. 

I did however drop the min to 45hz and raised the max to 65hz and it made no difference. 

When I switch to the generator, I can hear when the inverter tries to switch to the generator after 30 seconds but it immediately disconnects again without any load on the generator I suspect something else going on. Will be checking the earth tomorrow morning as it is a portable so could be something to do with that perhaps. 

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On 2021/08/23 at 8:14 PM, Sc00bs said:

Ok, gen frequency is 49.8hz which falls well within the min/max settings in the grid menu. 

I did however drop the min to 45hz and raised the max to 65hz and it made no difference. 

When I switch to the generator, I can hear when the inverter tries to switch to the generator after 30 seconds but it immediately disconnects again without any load on the generator I suspect something else going on. Will be checking the earth tomorrow morning as it is a portable so could be something to do with that perhaps. 

What about the voltage?

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On 2021/08/23 at 7:02 PM, branderplank said:

Thanks @YellowTapemeasure

Seems he did not report back on the matter.

However, that same grid screen says grid reconnect time = 60 seconds and power factor of 1.0

Could it be that the power factor of the genny is less than 1.0?

It does seems strange that in that thread that it sees the AC volts but 0 for frequency?

(this article seems to suggest that single phase gennies below 40 kw run at a PF of 1 - https://www.generatorsource.com/Industrial_Generator_Phases_and_Voltage.aspx )

I am not sure. I connected my own genny to the Aux port, works well.

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Plugged a socket tester into the generator to check the connections

The earth light flashes, so there seems to be something going on with the earth. 

Going to double check all the earth connections on the generator and hopefully that will sort it out. 

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Ok, so I am finally getting somewhere, I assume that the reason the connection between the inverter and generator was not happening was because the ground/earth of the inverter and generator are not the same so I connected the generator earth to the household earth.

I can now see the generator frequency getting reported in my home assistant panel pulling data from the inverter which is was not doing previously. 

It however is still not working as when the inverter starts putting load onto the generator, the generator slows down slightly which pushes it's frequency outside the allowed specs, so it kicks it out again and then waits for 30 seconds and then tries again, rinse & repeat!!

I think I am going to try connecting to the AUX port on the inverter and set it up for a generator which I see allows for a more gradual loading of the generator. 

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3 hours ago, Sc00bs said:

Ok, so I am finally getting somewhere, I assume that the reason the connection between the inverter and generator was not happening was because the ground/earth of the inverter and generator are not the same so I connected the generator earth to the household earth.

I can now see the generator frequency getting reported in my home assistant panel pulling data from the inverter which is was not doing previously. 

It however is still not working as when the inverter starts putting load onto the generator, the generator slows down slightly which pushes it's frequency outside the allowed specs, so it kicks it out again and then waits for 30 seconds and then tries again, rinse & repeat!!

I think I am going to try connecting to the AUX port on the inverter and set it up for a generator which I see allows for a more gradual loading of the generator. 

Glad to hear there is some change

Did you adjust your settings to not immediately start charging the batteries from the genny?

An alternative could be to drop some of the loads on the DB and progressively switch them on?

Lastly, is this during a time period where you have little to no solar power available?

 

 

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3 hours ago, Sc00bs said:

It however is still not working as when the inverter starts putting load onto the generator, the generator slows down slightly which pushes it's frequency outside the allowed specs, so it kicks it out again and then waits for 30 seconds and then tries again, rinse & repeat!!

Check if this can be of assistance:

 

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23 minutes ago, branderplank said:

Glad to hear there is some change

Did you adjust your settings to not immediately start charging the batteries from the genny?

An alternative could be to drop some of the loads on the DB and progressively switch them on?

Lastly, is this during a time period where you have little to no solar power available

5k genny does not support 8K+ load, I am pretty sure that is what it is.

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2 hours ago, Sc00bs said:

Thanks Branderplank, that looks very useful, will try it out. 

Hi John. 
 

Wire the gen into the Aux port and test for voltage at the Aux port and I’ll help you setup the inverter to charge from the gen. 

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11 hours ago, YellowTapemeasure said:

And charging batteries at the same time?

Load to the grid is load to the grid, I don't think that it makes any difference whether it is charging batteries or just serving the load in the house.

I generally don't charge my batteries with grid power in any case, unless there is load shedding coming and I want to make sure I have charged batteries for that.

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4 hours ago, Sc00bs said:

Load to the grid is load to the grid, I don't think that it makes any difference whether it is charging batteries or just serving the load in the house.

I generally don't charge my batteries with grid power in any case, unless there is load shedding coming and I want to make sure I have charged batteries for that.

The reason why I asked is because It depends on how it is set up. If it's servicing load and charging batteries simultaneously, your draw could theoretically exceed 8K, which isn't going to be possible with a 5k genny.   

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Hi Guys

Did some testing the weekend. So as I mentioned, I could not get this working previously. My approach, replace Municipal supply on Grid side with power from Genny (i.e. I don't use the AUX port). I have 7.5 Kva petrol GenTech genny.

So as experienced by @Sc00bs, you have to connect the earth of the genny to the earth of the house.

At first the Sunsynk could not see the Hz of the genny - which was around 53~44 without any load (based on a small digital screen from the genny).

So first I had to increase the upper range in the Grid settings to accept this (on the inverter).

As a side note:

  • My CT clamp was on the main incoming line, but my genny changeover switch is after this point, so I had to find a different spot for the CT clamp to allow the inverter to see the watts coming from the genny (i.e. I had to move it further up on the main incoming line)
  • My DB is split between Essentials and non essential with the more power hungry items (such as geyser, pool pump etc) on the N/E side

So after upping the Hz range, the relay clicked over after circa 60 seconds and the Sunsynk managed to synchronize with the genny. There was an immediate change in tone on the genny as if it was working harder (although I had ample solar power for UPS side and had switched off on the DB the pool pump and geyser)

Some interesting observations:

  • I was generating some good solar so that went to the battery and the UPS at the time
  • the more loads I added on the N/E side, the more the genny increased its power
  • With more and more loads on the N/E side, the Hz dropped to 51.5 as some point
  • The inverter kept on supplying only the batteries and the UPS side (essentials)
  • At some point I was drawing close to 4kw from the inverter and at this point, some of the LED long tube lights started some flickering

Before all of this, my expectation was however that the genny would idle along nicely since the inverter would now blend back to the N/E side since there was ample solar available and I did not have my system screen set to charge the batteries from the "grid" (i.e. I never instructed the inverter to try and charge from the batteries).

I mean this is what you get when you grid-tie with the Eskom grid, but contrary to this, the genny kept on working harder and no solar was diverted to the N/E

(I got fed up with the noisy generator and switch everything off and back to normal again).

So unfortunately, I did not try and charge the batteries from the genny but sure that it would be able barring in mind that you would have to limit the grid power as per the above video as it would probably start charging the at the prescribed BMS rate (in my case 111 Amps DC).

So the only conclusion from this is that for some reason, the Sunsynk cannot throttle the supply from the generator but I don't know what the technical reason for this could be and hence you got to be careful what you switch on when using the genny as the Solar power will not supplement the genny to extent that there is excess available and not charging the battery. (or the Sunsynk just doesn't like the genny waveform and don't want to blend with it - see flickering lights mentioned above)

I have some pics of the system flow chart if anyone wants to see these.

Hopefully this will be of use to someone.

 

 

 

 

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11 hours ago, branderplank said:

Hi Guys

Did some testing the weekend. So as I mentioned, I could not get this working previously. My approach, replace Municipal supply on Grid side with power from Genny (i.e. I don't use the AUX port). I have 7.5 Kva petrol GenTech genny.

So as experienced by @Sc00bs, you have to connect the earth of the genny to the earth of the house.

At first the Sunsynk could not see the Hz of the genny - which was around 53~44 without any load (based on a small digital screen from the genny).

So first I had to increase the upper range in the Grid settings to accept this (on the inverter).

As a side note:

  • My CT clamp was on the main incoming line, but my genny changeover switch is after this point, so I had to find a different spot for the CT clamp to allow the inverter to see the watts coming from the genny (i.e. I had to move it further up on the main incoming line)
  • My DB is split between Essentials and non essential with the more power hungry items (such as geyser, pool pump etc) on the N/E side

So after upping the Hz range, the relay clicked over after circa 60 seconds and the Sunsynk managed to synchronize with the genny. There was an immediate change in tone on the genny as if it was working harder (although I had ample solar power for UPS side and had switched off on the DB the pool pump and geyser)

Some interesting observations:

  • I was generating some good solar so that went to the battery and the UPS at the time
  • the more loads I added on the N/E side, the more the genny increased its power
  • With more and more loads on the N/E side, the Hz dropped to 51.5 as some point
  • The inverter kept on supplying only the batteries and the UPS side (essentials)
  • At some point I was drawing close to 4kw from the inverter and at this point, some of the LED long tube lights started some flickering

Before all of this, my expectation was however that the genny would idle along nicely since the inverter would now blend back to the N/E side since there was ample solar available and I did not have my system screen set to charge the batteries from the "grid" (i.e. I never instructed the inverter to try and charge from the batteries).

I mean this is what you get when you grid-tie with the Eskom grid, but contrary to this, the genny kept on working harder and no solar was diverted to the N/E

(I got fed up with the noisy generator and switch everything off and back to normal again).

So unfortunately, I did not try and charge the batteries from the genny but sure that it would be able barring in mind that you would have to limit the grid power as per the above video as it would probably start charging the at the prescribed BMS rate (in my case 111 Amps DC).

So the only conclusion from this is that for some reason, the Sunsynk cannot throttle the supply from the generator but I don't know what the technical reason for this could be and hence you got to be careful what you switch on when using the genny as the Solar power will not supplement the genny to extent that there is excess available and not charging the battery. (or the Sunsynk just doesn't like the genny waveform and don't want to blend with it - see flickering lights mentioned above)

I have some pics of the system flow chart if anyone wants to see these.

Hopefully this will be of use to someone.

 

 

 

 

Hi there. 
 

Whenever I have installed a genset to a Sunsynk, it was always on the AUX port and always worked well. Never had any issues with any size genset on any Sunsynk. 
 

The genset then charges the batteries and supplies power to the essential load simultaneously, provided it has capacity. It also blends with incoming PV. 

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23 minutes ago, Leshen said:

Hi there. 
 

Whenever I have installed a genset to a Sunsynk, it was always on the AUX port and always worked well. Never had any issues with any size genset on any Sunsynk. 
 

The genset then charges the batteries and supplies power to the essential load simultaneously, provided it has capacity. It also blends with incoming PV. 

That's exactly how my own cheap GenTech 7.5kVA genny is connected to my 5K Sunsynk, works well.

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1 hour ago, YellowTapemeasure said:

That's exactly how my own cheap GenTech 7.5kVA genny is connected to my 5K Sunsynk, works well.

 

1 hour ago, Leshen said:

Hi there. 
 

Whenever I have installed a genset to a Sunsynk, it was always on the AUX port and always worked well. Never had any issues with any size genset on any Sunsynk. 
 

The genset then charges the batteries and supplies power to the essential load simultaneously, provided it has capacity. It also blends with incoming PV. 

 

Good to know - thanks - but I assume it would only blend to the UPS side if the Grid went out?

 

And do you change any watt settings on the Aux screen? @Leshen

 

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4 minutes ago, branderplank said:

 

 

Good to know - thanks - but I assume it would only blend to the UPS side if the Grid went out?

 

And do you change any watt settings on the Aux screen? @Leshen

 

The genset when connected to the AUX port will only work when the Grid is offline. 
 

I limit the wattage to whatever the genset is rated at less 20%. 

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