System goes in Passthru a lot

Q&A and troubleshooting
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1

I finished making my first ESS system last week and I’m very happy with it. But when monitoring I see my Multiplus 2 GX going ‘off’, then ‘Passthru’, after about 10 seconds it resumes normal operation.

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This happens about 5 times per 15 minutes, and it doesn’t seem normal. I also can’t find anything about it on the web.

It happens when I use 1kW, but also when I only use 10W. All firmware is up to date, I checked my settings multiple times and everything seems to be setup correctly. The net voltage is fluctuating a little bit, but not more than +4 and -3 Volts, so well within the range. The frequency is also stable. I don’t get any error messages too.

(This setup is running parallel to my grid, I only use AC-in)

My system is build with the following parts:

  • Multiplus 2 GX 5000/48 - 70A
  • Cerbo GX
  • Smartshunt 500A
  • 4x LifePO4 200Ah Smart battery
  • VE.Bus MK2
  • VM-3P75CT Grid Meter (set to 1 Phase)

I use a 5x4mm2 cable for my AC-input (I use 1 Phase, 16Amps, the rest of the wires are not in use). The length of the cable is around 20 meters. The DC side is setup according to manual (70mm2 dc cables).

I do have a CAT7 cable (for the Grid meter) running parallel to my AC-cable to the installation, can some kind of interference cause this issue?

I hope someone recognises this issue, thanks in advance!

2

Some additional info:

My Multiplus is inverting power to the grid, but this does not show up on the graph above, it always says it’s in ‘Bulk’. Yesterday I fully charged the battery’s and ‘Absorption’ and ‘Float’ don’t show up here too.

-Another Edit-

I restarted the VE Bus system and after that I Redetected it.

As you can see in below picture, it shows the ‘off’ state, then the ‘inverting’ state. After that it returns to what it was before.

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Caught in the act:

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3

That is normal as it is in bulk production.
The float absorption is a battery state but you will only see that if you are not feeing back as the voltage (and current) will be remaining at bulk levels.

Is the inverter actually physically switching off and restarting?

Confirm the internal GX is completely disconnected?

4

The inverter stays on. It only goes in ‘off’ state and stops charging/inverting. After about 10 seconds it resumes operation.

Do you mean I have to physically disconnect the GX card in the Multiplus? I never opened it, so it’s not disconnected if you mean that

5

You can’t use 2 gxs in a system. I am wondering how everything is connected?

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6

Cerbo GX → Multiplus 2 GX (Ve.bus)
VE.BUS BMS V2 → Multiplus 2 GX (Ve.bus)

Grid meter → Cerbo GX (VE.Can 1/w. Resistor)
Smart shunt → Cerbo GX (VE.Direct 1)
Internet connection → Cerbo GX

I didn’t know that one couldn’t use 2 Gx’s in one system. Can I disconnect the GX card in the Multiplus?

7

Definitely.
Basically there are too many cooks in the kitchen.

With VE BUS and ESS control you should have one.

(To answer throughly here. You can connect two gxs together but it is for an entirely different reason you would be doing this.)

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8

I’ll disconnect the card later this afternoon, I’ll let you know if that solved the problem! Thanks for the advice!

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9

This solved my problem! I’m actually impressed that you found that small detail in my setup! (And I’m glad I wrote it down)

My setup is running for almost 2 hours without any hiccups. Thanks a million!

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1 Like
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