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wutduk asked

Losing AC Loads when Disabling AC-In via Virtual Switch or Programmable Relay


  • Multiplus 12/3000/120

  • 3 SmartSolar MPPT 100/50

  • 800Ah Battle Born Battery Bank

  • 1625 W Solar Array


My system was installed by a third-party, but since then I've been unable to get a response from the company. I was given little insight into how the system works, so I'm learning from scratch. Any help is appreciated. I recently moved into an RV and some of the time I'm connected to Shore Power. When connected to Shore Power, I want to limit the AC-In and utilize batteries and solar as much as possible. Only when the battery SOC drops to a certain level, or when the AC Loads exceed a certain wattage do I want to use Shore Power.


Whether I successfully disconnect AC-In using the Virtual Switch or via the Programmable Relay, once AC-In is cut, I also lose all AC-Loads (i.e., none of my AC appliances work), though DC Loads remain. Once I remove the Virtual Switch/Programmable Relay settings, all AC Loads return, along with AC-In. The only way I've managed to obtain (most) of the functionality that I'm after is by using an ESS Assistant, which is expressly forbidden for RVs*, so I'd prefer to use other options if possible.

Since I did not setup my system and since it's setup in a tight space, I can't get into my Multiplus to verify the wiring, but I believe my AC Loads are wired to AC1-Out (my understanding is that AC2-Out only works when AC-In is present).

*Note: I will disable the ESS Assistant prior to disconnecting from Shore Power to alleviate the concerns with disconnecting an RV while on ESS.

Does anyone have any ideas as to why this is happening and what I could do to resolve this?

ESSAssistantsvirtual switch
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1 Answer
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

The only thing I can think of at the moment is that the load's are connected to AC OUT 2. This should be the first thing to check.

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Thanks, @Matthias Lange - DE, for the quick response. It was my primary suspicion, but it's been hard to physically verify. I do plan on getting into the storage compartment and fully assessing the setup some day because I want to know how it all works. For now, that's just not practical.

When I look at the Multiplus via the CCGX, it does indicate AC-In L1 and AC-Out L1, but no AC-In or AC-Out for L2. Does this mean I have only AC-In/Out L1 only?

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1601144851660.png (28.1 KiB)

AC OUT 2 is not visible on the GX device.

You can overwrite the default behavior of AC OUT 2 by using the assistants.

You maybe have to update the firmware of the Multi to use the assistants.

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wutduk avatar image wutduk Matthias Lange - DE ♦ ·

@Matthias Lange - DE, something like this?

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1601153957248.png (16.6 KiB)

Yes, but have in mind that you always need at least two assistants, one for on and one for off.

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wutduk avatar image wutduk Matthias Lange - DE ♦ ·

If my AC Loads really are wired to AC2-Out, under what condition would I want to undo this change?

If under Shore Power, I have AC2-Out, but when AC-In is stopped via an assistant, I also lose AC Loads because of being wired to AC2-Out, when I then program an assistant to turn that on, I would want to leave that on. Once AC-In is restored via another assistant, I would still want to have AC2-Out on, right?

I could make an assistant that functions opposite to the screenshot above to effectively "undo" the first assistant's change, I'm concerned that I would "lose" AC2-Out upon allowing AC-In again.

I hope that makes sense.

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Good morning from Germany. :)

For normal operation I would use something like that:

The delay for AC IN is important to let the Multi some time to synchronize with the grid, switch over to grid and start charging before you turn on your loads again.
For relay (1) you have to look how high the voltage rises without load after the cut-off and set it slightly above that value to prevent switching on/off/on/off ...
The voltage for relay (2) should be above the cut-off voltage of the BMS of the batteries.

For testing if your loads are connected to AC OUT 2 you could set relay (1) slightly under the current voltage and relay (2) about 0.1V lower than relay (1).
After you send the settings AC OUT 2 should turn on after the set delay and your loads should get powered up, then you turn on some loads and if the voltage drops under the value of relay (2) your loads should turn off.

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wutduk-normal.png (18.2 KiB)
wutduk avatar image wutduk Matthias Lange - DE ♦ ·

Well, I tried this and I didn't get the hoped-for result (i.e. When AC-In was killed by the programmable relay assistant, my AC Loads were still stopped. Either I didn't define the AC2-relay assistant correctly, or perhaps my loads really aren't connected to AC2-Out (again, it's not something I can easily confirm myself at this time, but some day I will definitely make a point to get into the Multiplus and find out).

Thanks, @Matthias Lange - DE, for your assistance. I will update this should I make any substantial progress.

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Ok, than maybe the Multi don't have a connection to the battery!?
A blown fuse maybe?!

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wutduk avatar image wutduk Matthias Lange - DE ♦ ·

I just realized I never specified that my AC Loads work just fine when not connected to Shore Power. My inverter kicks in and powers my AC Loads from the battery bank as expected. It's only when the AC-In is programmatically disconnected via the Virtual Switch or the Programmable Relay that I suddenly lose my AC Loads (the CCGX will show AC-In as "--" and the AC Loads as "0w"). This is probably useful information that I never made clear before.

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