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Isolating the Neutral

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(@chg_coin)
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Joined: 4 years ago
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Well I'm still trying to get it to work but I'm afraid to proceed so I am waiting for some guidance.  Is the problem just that I need to make sure that the same ground is not shared by the generator and the inverter?  If so, would changing the generator from floating to bonded neutral and then fully separating the two grounds do the trick?  And if so, what is the amperage utilized by the battery charger, so I can know how much generator power I need?  Lastly, <a contenteditable="false" data-ipshover="" data-ipshover-target="/profile/2-sid-genetry-solar/?do=hovercard" data-mentionid="2" href="/profile/2-sid-genetry-solar/" rel="">@Sid Genetry Solar you had mentioned there might be something crossed somewhere, is this something I need to change inside the case before proceeding or do you think we are good there?

<a contenteditable="false" data-ipshover="" data-ipshover-target="/profile/8-waterman/?do=hovercard" data-mentionid="8" href="/profile/8-waterman/" rel="">@Waterman I bought that manual ATS you had suggested - can this be used on the input side, the output side of the inverter, or perhaps either depending upon the application?

Thank you.


   
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(@waterman)
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Posts: 313
 
Posted by: @chg_coin
Well I'm still trying to get it to work but I'm afraid to proceed so I am waiting for some guidance. Is the problem just that I need to make sure that the same ground is not shared by the generator and the inverter? If so, would changing the generator from floating to bonded neutral and then fully separating the two grounds do the trick? And if so, what is the amperage utilized by the battery charger, so I can know how much generator power I need? Lastly, @sid-genetry-solar you had mentioned there might be something crossed somewhere, is this something I need to change inside the case before proceeding or do you think we are good there? @waterman I bought that manual ATS you had suggested - can this be used on the input side, the output side of the inverter, or perhaps either depending upon the application? Thank you.

Depending on your need, either side and what you are trying to accomplish.


   
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(@sid-genetry-solar)
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Posts: 2883
 
8 hours ago, CHG_Coin said:

Well I'm still trying to get it to work but I'm afraid to proceed so I am waiting for some guidance.  Is the problem just that I need to make sure that the same ground is not shared by the generator and the inverter?  If so, would changing the generator from floating to bonded neutral and then fully separating the two grounds do the trick?

Sorta...not quite.  It does appear that the input terminal wires are reversed from what's labeled on the chassis; this is only a problem if ANY of the "input" circuit wires are tied to an "output" circuit wire.  However, there has to be some hidden gremlin with the wiring causing the "transformer polarity" error--likely some unexpected ground-neutral bonding point.

If you turn the inverter off, and start the generator (connected to the inverter), do you measure any voltage on any of the output terminals?  (i.e. O-L1 to O-L2, or O-N to O-l1, etc.)  If so, this would pretty clearly indicate an external wiring issue, where the GS inverter can't fully disconnect the generator--which would cause all sorts of problems.  Still trying to source a 70A 2-pole relay for the Rev. C GS board design...

8 hours ago, CHG_Coin said:

Lastly, <a contenteditable="false" data-ipshover="" data-ipshover-target="/profile/2-sid-genetry-solar/?do=hovercard" data-mentionid="2" href="/profile/2-sid-genetry-solar/" rel="">@Sid Genetry Solar you had mentioned there might be something crossed somewhere, is this something I need to change inside the case before proceeding or do you think we are good there?

This isn't a problem per se, just so you're aware that the "I-N/L2" terminal actually is the "I-L/L1" terminal, which bridges to O-L1 when the relay actuates.  This also means that the terminal marked "I-L/L1" is actually hardwired to the O-L2 terminal.

8 hours ago, CHG_Coin said:

And if so, what is the amperage utilized by the battery charger, so I can know how much generator power I need?

Adjustable 😉.  This is the CFG -> Battery / Charge -> Charge Amps (note that it's in percent, not amperage; I haven't had the time to scale this to a rough amperage number.)  The percentage is based on the wattage rating of the inverter, but the actual scale is determined by the transformer setup (for 12/24/36/48v, as well as whether it's 120v or 240v charge).


   
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(@chg_coin)
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Joined: 4 years ago
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Topic starter  
Posted by: @sid-genetry-solar
Still trying to source a 70A 2-pole relay for the Rev. C GS board design...

You might try Marshall Wolf who sells really nice hockey puck style SSR's, such as Carlo Gavazzi.  This is what we used for our project but they make other kinds too -  https://www.wolfautomation.com/ssr-2-pole-common-control-zero-cross-zc-27193/?gclid=Cj0KCQjwsqmEBhDiARIsANV8H3ZCy8z5UN-er5_mBZNmgq_ZADlFFjUDedPibqRDkPsGeMjBWFB6la4aApZpEALw_wcB#description

I'll try again to get the voltages you had asked for and get back to you, thanks!


   
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(@sid-genetry-solar)
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Joined: 4 years ago
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I personally don't want an SSR for several reasons:

  • very pricey
  • limited avalanche rating, easily damaged with AC line surges.
  • high voltage drop (easily >1.2v at full load), they generate a LOT of heat

I'm trying to get a 70A latching relay customized for our needs...they use no power to maintain state, have next to zero voltage drop, and can handle large voltage surges (in off state) without failing.  Considerably cheaper, too.

The only plus-side for an SSR is that I can pinpoint with laser precision when they'll turn on.

 

Though that's not to say that you couldn't hack the GS inverter (Rev A.1 only BTW) to use your SSR for the AC input relay, disconnecting both AC input phases, solving the ground bonding issue altogether.  At your own risk, of course 😉.


   
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