Feedback or max continuous pass through current as it is referred to for a 5 KVA unit is 35 amps. It would be advisable to use a min. of 6 mm wire.
As per the spec sheet, an 8000watt unit standard output current is around 35 amp and the max pass through current is 50 amp, best you dont install anything less than 10 mm.
Feedback is not the same as let through.
Feedback is just what the excess PV does. Where it goes to the non essential circuits.
Let through allows for the 5kw to use up to 5kw of PV and battery and then an additional 3kw from the Grid.
So you can run more than the 5kw on the essential circuits.
This can look like the hairdryer, washing machines, vacume can run which is greater than the 5kw but the inverter now won't shut down (if grid is available) to supplement the extra load.
I must say that is how I understand it and tell clients. If I have it wrong please let me know
I have done only 1 Sunsynk so I am by no means expert haha
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I am still trying to figure this out, feedback and pass through.
Feed back is controlled by the CT coil from the solar panels back to the non essential or grid side of the inverter or to export back to the grid.
Pass through is the current that can be supplied to the essential load via the UPS/essential side , ie: an 8 kw can handle 12 kw.
Still a bit sketchy with this information.
Yes that's how I have it too
It's nice as the cheap inverters the moment 5kw is on pulled the thing shuts down.
Also some houses not possible to rewire circuits to take the dishwasher, washing machine off the essential circuits as it powers the internet for example so the pass through is great as then they can still run when there is grid.
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Which brings me to selecting the inverter size, why are customer offering 5 kva units used a a backup can only run at a small percentage of the available power.
The same problem we have when connecting a 5 KVA or smaller generator to a main DB.
We are seeing problems with that logic - If the dishwasher , washing machine etc is running and there is a dip in power then the inverter trips because the essential side is overloaded . It also runs the battery down quickly if the people do not realize that the grid has dropped out.Originally Posted by Dylboy
Yes that's how I have it too
It's nice as the cheap inverters the moment 5kw is on pulled the thing shuts down.
Also some houses not possible to rewire circuits to take the dishwasher, washing machine off the essential circuits as it powers the internet for example so the pass through is great as then they can still run when there is grid.
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It is much safer/a requirement, to ensure that the load can never exceed the essential side output. Clause 7.12.2.4 ( pasted below) requires you to ensure that the capacity is not exceeded.
Rather use the feedback function ( as put so eloquently by Justloadit further up ) to supply the non essential loads with solar and a set percentage of battery to compliment the grid usage.
If it is purely back up then ensure that any possible load that could be connected and running is covered by the sizing of your unit.
Next you will be saying that the client does not want to pay extra to wire extra circuits to the TV, Router , Alarm and limited lights and so you do as he requests with the money he says is available.
This is why the industry is where it is, as the client that has no electrical knowledge and taking no responsibility when something goes wrong is determining how we as professionals are doing our jobs and take the risks.
If your doctor says , Hey bud you need a triple bypass , you don't say , Hang on I only have money for one valve to be bypassed and then your wife sues him when he does only one , leaves the other 2 and you drop dead a month later - He just says go elsewhere if you are not taking my professional opinion seriously , it is 3 valves or none. The risk of having a comeback is to high and I am walking away , go find someone else that is prepared to put his practice at risk. You won't find that person because the doctors all stick to doing what is correct, not what financially suits you.
Why do we do differently ?
7.12.2.4 Where the alternative supply is intended to provide a supply to an
installation that is not connected to the main supply, or to provide a supply as
a switched alternative to the main supply, the capacity and operating
characteristics of the alternative supply shall be such that danger or damage
to equipment does not arise after the connection or disconnection of any
intended load as a result of the deviation of the voltage or frequency from the
standard range. Means shall be provided to automatically disconnect such
parts of the installation, as may be necessary if the capacity of the alternative
supply is exceeded.
Why do we do differently?
The same reason people are doing COC's for R650 and you can get a socket outlet installed at R450 per point ?
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