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Thank you for the great forum, Safe Driving over the weekend. Sincerely Jason
Radar

UPDATE: Some progress -- Mecer 5kva inverters - want to run in 'SUB' mode

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13 minutes ago, pilotfish said:

you are a real sweatheart

Eish, one male calling another a sweetheart ... o my! :D:D:D:D

I just could not refuse! 

Do agree with Politfish ... the numbers where over optimistic, not all have done the "upgrades" to more efficient electricity usage, even though that should be the first step.

Sometimes it is just cheaper to upgrade the inverters capacity than to go and replace all.

One can go left / right / over a obstacle placed in your way. I personally, like to blow it up, or shoot it, like Fiona in Burn Notice. :-) 

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9 minutes ago, plonkster said:

In this day and age you can identify as whatever you like and demand to be addressed as such :-)

As right as you are, I dare anyone to try that in SA, "tussen die manne" ... :D

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22 hours ago, Radar said:

how do I ensure the health of the 4 x 100ah batteries (Vision is the make/model as far as I know), without a BMV and ICC ?

At the absolute minimum you should install the HA-02 referred to in the posts above.

22 hours ago, Radar said:

what settings (I'm an electrical ignoramus) for the batteries DOD/SOC should I be using on the inverter panel directly, assuming I will continue without a BMV and ICC ? 

Without BMV/ICC your Axpert settings are voltage based and very inaccurate - but if you want to give it a go and hope for the best then try the following;

  • Menu 05 = USE
  • Menu 12 = 47/48 (48 is better but may cause early switching when high current is drawn and battery voltage sags momentarily)
  • Menu 13 = If your system is mainly for Eksdom backup then go high like 56, otherwise the default 54 is ok
  • Menu 26 = 57.6 (Vision battery is @ 14.4 to 14.7, = 57.6 to 58.8, but with Axpert you want to avoid the 60V mark)
  • Menu 27 = [if batteries are cycling daily I would use high number like 56, if batteries are mostly standby then 54/55)
  • Menu 29 = [I think 46 is OK, 44 at a push, but the default 42 is too low]
22 hours ago, Radar said:

the electrician suggested that if I put a solar based heating element into the geyser,

The Geyserwise Solar system is is a great system, it is usually a +/- 1kW DC element and a +/- 2kW Grid element in one and controlled by a Geyserwise Max controller - you will need about 3x 300W panels for it to work properly on the Hiveld. It will heat the water using the DC element via the 3 panels during sunlight hours, and then switch to grid mode to boost the temp if required at a time and temp according to your settings (normally 55C at 4-6 am and 4-6 pm). No plumbing involved which is the benefit.

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On 2018/08/01 at 11:57 AM, pilotfish said:

At the absolute minimum you should install the HA-02 referred to in the posts above.

Without BMV/ICC your Axpert settings are voltage based and very inaccurate - but if you want to give it a go and hope for the best then try the following;

  • Menu 05 = USE
  • Menu 12 = 47/48 (48 is better but may cause early switching when high current is drawn and battery voltage sags momentarily)
  • Menu 13 = If your system is mainly for Eksdom backup then go high like 56, otherwise the default 54 is ok
  • Menu 26 = 57.6 (Vision battery is @ 14.4 to 14.7, = 57.6 to 58.8, but with Axpert you want to avoid the 60V mark)
  • Menu 27 = [if batteries are cycling daily I would use high number like 56, if batteries are mostly standby then 54/55)
  • Menu 29 = [I think 46 is OK, 44 at a push, but the default 42 is too low]

So I have set all of these as per the suggestion above.  The system is not reporting a fault: 4 with little triangle, which is a battery low warning.  Why would that happen?

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Fault 4 = low battery warning

It says that your batteries have dropped below the setting in Menu 29 - you could lower the setting back to the default of 42V which get rid of that warning, but you would be killing your batteries taking them that low (if they aren't already damaged).

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9 hours ago, pilotfish said:

Fault 4 = low battery warning

It says that your batteries have dropped below the setting in Menu 29 - you could lower the setting back to the default of 42V which get rid of that warning, but you would be killing your batteries taking them that low (if they aren't already damaged).

Thanks Pilotfish.  Surely one of those settings is the threshold for charging to restart i.e. that the warning should never have come up in the first place?

The batteries are less than 3 months old, so I really hope its not because they are damaged.  As the setting on menu 29 was on 42v previously, and I changed to 46v, is it possible they just happened to be between those two when I changed the settings?

Menu 16 is on CSO, and I changed to OSO as well when changing the above, perhaps thats why it got caught inbetween the old and new on 29?  16 is back on CSO now, but I also reset all of those settings to the ones they had before i.e. menu 5 to AGN etc.

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25 minutes ago, Radar said:

Thanks Pilotfish.  Surely one of those settings is the threshold for charging to restart i.e. that the warning should never have come up in the first place?

Hi Radar

With the vanilla firmware if inverter voltage is within 4V of setting 29  low battery voltage alarm. If you have set 16 to OSO this alarm will only clear once there is sun on the panels and some charging takes place.

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2 minutes ago, Chris Hobson said:

Hi Radar

With the vanilla firmware if inverter voltage is within 2V of setting 29  low battery voltage alarm. If you have set 16 to OSO this alarm will only clear once there is sun on the panels and some charging takes place so that battery voltage is 4 V higher than setting 29.

 

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On 2018/08/10 at 8:06 AM, Chris Hobson said:

 

Thanks.

If setting 16 is set to CSO, will the alarm never come up?  if it does, what could be the problem?

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7 hours ago, Radar said:

If setting 16 is set to CSO, will the alarm never come up?  if it does, what could be the problem?

.....Hmmm never say never :P.. It should not come up or if it does it should come up very briefly. 

I think that you have setting 12 at 47/48V and if the inverter dips below this then load would go to grid (bypass) and the batteries will charge either with solar or utility. The initiation of charging would quickly lift battery voltage to 50V and that would be 4V higher than setting 29 at 46/45V.

If setting 12 is 48V and setting 29 is 45V then I am almost certain the alarm will never sound as battery voltage is always going to be more than 3V higher than the battery low cutoff (setting 29) and therefore 1 V than the alarm threshold.

I would get a BMV and use ICC to have greater control of battery discharge.

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Ok next question:

I have two Axpert inverters.  The solar panels (12) are all connected to the Master.  The Slave's LCD display screen shows that the load its responsible for is being powered by the battery (i.e. no solar panel on its display).  The master shows the load is being powered by the solar panels, and the solar panels are charging the batteries.

Shouldn't the Slave's load also be powered by the solar panels (setting 01 is SOL) ?  Is the LCD panel display not 100% accurate, or should some of the solar panels have been connected directly to the Slave ?

 

 

image2.jpeg

image1.jpeg

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The slave has no solar panels therefore it cannot power the load using PV it has to use energy from the battery. 

The master is powering its portion of the load from PV and charging batteries. Portion of this battery charging energy is directly being used by the slave as both inverters are connected to the same nodes via the batteries.

 

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12 hours ago, Chris Hobson said:

The slave has no solar panels therefore it cannot power the load using PV it has to use energy from the battery. 

The master is powering its portion of the load from PV and charging batteries. Portion of this battery charging energy is directly being used by the slave as both inverters are connected to the same nodes via the batteries.

 

Thanks Chris.

 

Can the Axpert Master 'share' the power from the solar panels with the Slave? 

If so, is it a setting change only? or how?

If not, is the only remedy then to take e.g. half of the solar panels and wire them directly to the Slave?

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No necessary - There are no losses from the  slave using the master's charging current as a source. It is like going shopping with the trolley and your kids put chocolates and sweets into the trolley. You just take them out of their hands and put them back before they put them in the trolley. No harm done. 

If fact you now have a spare MPPT and in future you could add panels perhaps with a different orientation to boost early morning charging.

Addition: This is my exact setup at the moment until I have laid a second homerun(after digging up the lawn) and installed 6 extra panels.

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1 minute ago, Radar said:

Thanks Chris.

 

Can the Axpert Master 'share' the power from the solar panels with the Slave? 

If so, is it a setting change only? or how?

If not, is the only remedy then to take e.g. half of the solar panels and wire them directly to the Slave?

No, you need to physically connect some panels to both inverters, for both inverters to have some solar energy. Each inverter has it's own MPPT. 

But, it does share the generated power, from either battery or solar, on the 220V output side. And both inverters will charge the batteries, if there is Eskom feed, but only the inverter with the solar (i.e. the Master inverter in your case) will charge batteries from the solar panels

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6 minutes ago, Chris Hobson said:

No necessary - There are no losses from the  slave using the master's charging current as a source. It is like going shopping with the trolley and your kids put chocolates and sweets into the trolley. You just take them out of their hands and put them back before they put them in the trolley. No harm done.

Isn't there 'wear and tear' on the batteries unnecessarily ?

My intention with the batteries is that they are purely back to Eskom.

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6 minutes ago, SilverNodashi said:

No, you need to physically connect some panels to both inverters, for both inverters to have some solar energy. Each inverter has it's own MPPT. 

But, it does share the generated power, from either battery or solar, on the 220V output side. And both inverters will charge the batteries, if there is Eskom feed, but only the inverter with the solar (i.e. the Master inverter in your case) will charge batteries from the solar panels

Thank you.

 

My current setup does seem to be inefficient as i have 12 x 330w solar panels, and that is more than enough to handle my 'regular day time' load.  Therefore if the slave is charging the batters from eskom, its inefficient and unnecessary cost for me, and if the slave is using batteries instead of solar directly, its also using the batteries unnecessarily.

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2 minutes ago, Radar said:

Isn't there 'wear and tear' on the batteries unnecessarily ?

My intention with the batteries is that they are purely back to Eskom.

No the energy never reaches the batteries. The current at a node is a sum of all inputs and output equals zero. So if your master is charging at 10A and the slave  uses 8A then only 2A goes to battery.

If master is "charging" at 10A and slave is using 15A then obviously the battery will supply 5A.

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10 minutes ago, Radar said:

Thank you.

 

  Therefore if the slave is charging the batters from eskom, its inefficient ......

That aspect had not crossed my mind. Just disable grid charging set program 16 to OSO.

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1 minute ago, Chris Hobson said:

No the energy never reaches the batteries. The current at a node is a sum of all inputs and output equals zero. So if your master is charging at 10A and the slave  uses 8A then only 2A goes to battery.

If master is "charging" at 10A and slave is using 15A then obviously the battery will supply 5A.

Then the LCD display on the Slave is deceiving. 

 

Using the first scenario as the relevant one (10A, 8A and 2A), and as the total load on the system was 374w (173w slave and 204w master), it should in theory all have been covered by the solar panels (330w x 12 x 90% effectiveness estimate = 3.6kw).    Then I have no need to 'worry' ?

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14 minutes ago, Radar said:

Then the LCD display on the Slave is deceiving. 

Jip  Currently my Master is charging at 24A and the slave is discharging at 23A and ICC says charging 4A. So if you can accept that the Axpert rounds up/down then the figures tally (more or less). If grid charging is an issue then set grid charging for the unit without the panels to 2A. That way you can still have grid charging for the main inverter in the absence of solar and there will be less for you to worry about (automated).

 

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1 hour ago, Radar said:

Then the LCD display on the Slave is deceiving. 

Not really. It's being honest with you. As far as it (the slave) is concerned, it's getting that power from the battery. It isn't actually coming from the battery, as Chris explained, it comes from the "DC bus" which just happens to be supplied by the MPPT of the other inverter... but the slave doesn't know this.

(And if I was the programmer who wrote that, there'd be no way in hell I'm complicating things by adding some way for the remote inverter to know this :-) ).

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