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The guy doing my install said why they don't use the thin dc strand for AC is because there is lots of little sparks between the inner part of the cable. The solid core is to limit the sparks between

There are 3 connections on the inverter.  Grid connection. This is the grid input connection but is also an output if the grid is available. If there are loads after the municipal meter but befor

With regard to the sound of the 8kw inverter. Within 6m you still here it clearly. It switches on and off so no even noice. I will not install it close to me. Spend a little and put it in the garage. 

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On 2020/08/20 at 12:51 PM, Halcyon said:

Hi Johan, do a voltage check between load neutral and earth when AC grid is off.  One of the Sunsynk manuals specifically states you will read 110v with a floating neutral unless resolved with a relay.  My load output neutral earth measured +- 50V when in island mode but this was resolved when I installed a relay.  The 50V gave me a little bite when touched. Surprisingly my E/L did trip when you press the test button without relay installed but I was told that is not a reliable test for safe functioning.  The Sunsynk definitely does not have an internal relay doing the bonding job like a Victron.  I bought a R100 40A NO relay from ACDC.  It is so small I fixed it with cable ties inside the inverter.  As you know there is a lot of space inside once you open the front cover.

@HalcyonDo you perhaps have the product code for that relay? Voltex this side is useless and would like to order a couple to use with my future installations.

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On 2020/09/27 at 9:04 AM, Johann1982 said:

@HalcyonDo you perhaps have the product code for that relay? Voltex this side is useless and would like to order a couple to use with my future installations.

Hi Johann, Yes the one I have is the same as Justin's as per the link he posted.  Just marked as 12V somewhere in error on the page but must be the 230V 40A version.

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On 2020/09/27 at 11:07 AM, Bloubul7 said:

I used a 60a solid state relay from Communica.  Might be a little overkill but should last

https://www.communica.co.za/products/ksi600a60-l

20200927_110424.thumb.jpg.33b0d158d2bc0865d81298f766a1d740.jpg

"Solid state relays" do not provide electrical isolation.  When the MOSFETs on the solid state relay fails, it'll fail short circuit.  Mechanical relays don't have this problem.  You really should not be using that relay.

EDIT: Also it looks like your are connecting the relay using a low voltage circuit?  If that is the case, you've effectively removed the isolation from the low voltage circuit.  A very big no-no.  Anything connected to that low voltage circuit (including network cables) can become live.

Edited by Gnome
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12 minutes ago, Gnome said:

"Solid state relays" do not provide electrical isolation.  When the MOSFETs on the solid state relay fails, it'll fail short circuit.  Mechanical relays don't have this problem.  You really should not be using that relay.

EDIT: Also it looks like your are connecting the relay using a low voltage circuit?  If that is the case, you've effectively removed the isolation from the low voltage circuit.  A very big no-no.  Anything connected to that low voltage circuit (including network cables) can become live.

Thanks,

Will replaced it with a mechanical relay.  It is driven by 220V, the inverter provides a 5 amp 220v islanding switch

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3 minutes ago, Bloubul7 said:

Thanks,

Will replaced it with a mechanical relay.  It is driven by 220V, the inverter provides a 5 amp 220v islanding switch

Actually I stand to be corrected:  They internally do use opto-isolator to create isolation: https://www.electronics-tutorials.ws/power/solid-state-relay.html

Just verify in the specification of the relay you bought that it does actually isolate.

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2 hours ago, Gnome said:

"Solid state relays" do not provide electrical isolation.  When the MOSFETs on the solid state relay fails, it'll fail short circuit.  Mechanical relays don't have this problem.  You really should not be using that relay.

I think you may be confusing failure modes... Solid state relays are all isolated, and pretty much only a lightning strike could break down the control to load isolation.

The main safety drawback of SSRs is that the primary failure mode is fail-closed - i.e. if the output fails, it fails in such a way that it carries on conducting.  Mechanical relays can fail closed, but it is extremely rare (something like 1:10^7 for typical relays) - if they fail, they usually fail open - i.e. load disconnected, which is generally a much safer failure mode.

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14 hours ago, JustinSchoeman said:

I think you may be confusing failure modes... Solid state relays are all isolated

To be honest with you, I figured from first principles.  Only after did I go read more about it.  I knew that solid state relays were just MOSFETs.  And MOSFETs always fail short-circuit.  However the opto-isolators is pretty decent isolation.  The reason I thought this is because you don't typically expect a relay to consume current on the switching side, only the coil side.  Bit of a drawback with using them I guess.

14 hours ago, JustinSchoeman said:

only a lightning strike could break down the control to load isolation.

Most opto-isolators are rated roughly 4kV, so it doesn't take *that* much to break the barrier (lightning tests typically start at 200kV up to 1MV).  In terms of break-down voltage it is much easier to get higher kV ratings using opto-isolators than relays anyway.  Isolation is more about failure mode than breakdown voltage.

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  • 2 weeks later...

Anyone with more than 8kwp of panels and the sunsynk 8kw inverter? 

Yesterday I had my first 50kwh of pv production and the display on the inverter seems to only record 50kwh and stops counting pv production beyond this. 

Today looks like another 51kwh solar day and the inverter stopped recording pv production. 

Edited by Achmat
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36 minutes ago, Werner67 said:

Hi Achmat

I do record more that 50kw a few times when able to use all the power.

have 8.6kw of panels.

Sunsynk support updated my device on Friday so now the inverter shows the full pv production. 

Seconds pic was before the update. 

Screenshot_20201016-183953_Gallery.jpg

Screenshot_20201018-203810_Photos.jpg

Edited by Achmat
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  • 3 weeks later...
  • 2 months later...

Hi Guys

Many different topics discussed on this thread and very interesting.

The manual however does not state the rating of the relay required but just that the ATS pins should be connected to the relay.

So why would you need a 40Amp relay if there is going to be no (or minimal) current flowing through the relay - i.e. you don't expect to have 40 amps flowing between N and E? If I understand the function of the neutral - earth bond correctly, this bond is required in order to give the RCD/EL breaker the ability to detect if there is a fault and accordingly, any such variance detected (less than 30mA if I understood it right) will cause the RCD to trip and "break" the current that is being leaked?

Hope I explained this correctly.

 

As a side note, we should convert the latest copy of the PDF manual and make some track changes with all the learnings/additional Q&A and fix up some of the obvious grammar and other errors. Should we start a thread for this?

 

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