question

Huub avatar image
Huub asked

ET340 not connected and then connects (repeatedly) but only when PV production is high

ET340 connected to Multiplus II GX 5000 to control ESS. Battery 4 Pylontech US3000C batteries BMS active (Pylontech BMS on can bus)

AC connected to ACin only.

The system works correctly in ESS mode as long as PV input is low. As soon as PV production is in excess of ?2000W?, the ET340 drops repeatedly connection. So the ESS-system first reports 'external control' and is charging the batteries, then goes to passthru, (and reports discharge for 10 seconds, and then ET340 reconnects and the cycle repeats

In DVCC I limited charge current to 50A.

How to remedy the connection drop of the ET340 and get proper ESS control?

Thanks in advance


Energy Meter
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

13 Answers
Jason - UK avatar image
Jason - UK answered ·

' an extension USB cable'

@Hu2bPV can you use the system without the extension cable? Extension cables create too much volt drop so the data transfer from RS485 to USB will become unstable. I would recommend using a powered USB hub but I like many others are yet to find one that works also without creating meter disconnects.

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Jason - UK avatar image
Jason - UK answered ·

@Hu2bPV Im seeing 2 separate issues, Batteries stopping charge, im assuming from the battery BMS due to too high current, and a grid meter disconnecting due to the use of a USB extension cable. Try limiting the charger in the victron settings and see if that makes a difference.

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Huub avatar image
Huub answered ·

I apologize for any confusion.

I delayed posting this note in the hope of discovering a fault that wasn't a result of my own error. Unfortunately/fortunately, it appears that the issue originated from not fully removing the insulation around the ground cable. I stumbled upon this revelation while manipulating the ET340; touching it replicated the problem, prompting me to reevaluate the connection.


I've attached a graph depicting battery voltage and current. Despite a heavier load, the system consistently maintains its performance.

screenshot-2024-01-13-at-091948.png

On a positive note, the USB3 hub has proven to work seamlessly, although its necessity remains uncertain. For now, I'll keep it as is.


I appreciate your collaboration and thoughtful consideration.


screenshot-2024-01-13-at-091948.png (173.8 KiB)
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Huub avatar image
Huub answered ·

Screenshot 2023-12-20 at 16.32.39.pngScreenshot 2023-12-20 at 16.30.00.png

above graphs of the PV production and the erratic ESS behaviour .

Any ideas for ET340 disconnect? or is it interaction between BMS of the batteries and the ESS system? Or is there a problem with conversion of the analog data to a digital signal?

Thanks in advance for any suggestion how to proceed...


screenshot-2023-12-20-at-163239.png (317.7 KiB)
screenshot-2023-12-20-at-163000.png (188.4 KiB)
1 comment
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Huub avatar image Huub commented ·

screenshot-2023-12-23-at-125439.pngscreenshot-2023-12-23-at-125625.png

screenshot-2023-12-23-at-125401.png

screenshot-2023-12-23-at-125753.png

Some images above to illustrate the erratic behaviour of the ESS.

I hope to somebody can explain to me why I see large swings in battery charging power.

Is there something wrong with the ET340? Is the battery too cold (and is the Pylontech BMS interfering here ) or ??

Any comments well appreciated. Thanks

0 Likes 0 ·
screenshot-2023-12-23-at-125753.png (240.2 KiB)
screenshot-2023-12-23-at-125625.png (174.0 KiB)
screenshot-2023-12-23-at-125401.png (178.3 KiB)
screenshot-2023-12-23-at-125439.png (192.5 KiB)
Jason - UK avatar image
Jason - UK answered ·

@Hu2bPV Regarding the ET340 disconnect, how is the ET340 connected to the GX device?

It might be prudent to take things back to basics just in case you have 2 different issues creating confuling situation. If you disconnect the PV and just use the batteries as an BESS, do you get any issues still?

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Huub avatar image
Huub answered ·

Thanks Jason.

The ET340 is connected using a RS485 to USB interface with an extension USB cable.

The system works well for days as long as the PV input is not in excess of say 2000 W.

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Huub avatar image
Huub answered ·

screenshot-2023-12-23-at-135101.png

The image illustrates that only with high PV input there are large swings in power input to the battery (on the 20th of December and again today)


screenshot-2023-12-23-at-135101.png (231.5 KiB)
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Huub avatar image
Huub answered ·

Thanks for the suggestion Jason.

The distance between ET340 and victron is 8 m... I can use maybe some CAT6 cable to extend the RS485 to USB interface cable ? or use a powered USB hub yes....

1 comment
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Jason - UK avatar image Jason - UK commented ·
Ive tried 3 different USB powered hubs yet and I'm yet to find a stable powered USB hub. Each one I have bought has been a recommendation on this forum.
0 Likes 0 ·
Huub avatar image
Huub answered ·

I will limit charging to 40 A and see if that solves the problem. ...

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Huub avatar image
Huub answered ·

screenshot-2023-12-23-at-140354.png

clouds solved the problem for now.

I did set 40A charging limit in DVCC and limited charging power in ESS settings to 2000W.

thanks again for the suggestions Jason. (wait and see)


screenshot-2023-12-23-at-140354.png (209.8 KiB)
1 comment
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Huub avatar image Huub commented ·

ok the gods of the clouds have an off day so a nice ramped up PV-production curve

What I see is that initially system is working nice : excess solar power stored in he batteries and grid put hovering around the set-point of 70W grid input

With increasing PV the representation of what is going on is intermittently disturbed:

screenshot-2023-12-24-at-104621.png

incorrect but charging still ok


screenshot-2023-12-24-at-104805.png

incorrect (grid and AC loads for L1 only presented; no total is given) charging still correct (around the set limit of 2000 W)

screenshot-2023-12-24-at-104819.png

correct again

screenshot-2023-12-24-at-104909.png

only L1 for Grid and AC loads

screenshot-2023-12-24-at-104926.png

further degradation of representation what is going on

screenshot-2023-12-24-at-105040.png

system trips : battery discharging now with 20W

screenshot-2023-12-24-at-110046.png

this tripping repeats itself


I then turn on an electric heater (750W) on L1 and the system is behaving normally again:screenshot-2023-12-24-at-111858.png


I'm puzzled by the observations especially regarding the representation in VRM what the ET340 'reports' and how it misrepresents what is going on

Also it is puzzling to see that reducing excess power by turning on a heater on L1 is solving the tripping problem (effect of BMS?? but why?)

I hope you all find it interesting to see and I look forward to your comments. Thanks

0 Likes 0 ·
screenshot-2023-12-24-at-104621.png (171.7 KiB)
screenshot-2023-12-24-at-104805.png (199.6 KiB)
screenshot-2023-12-24-at-104819.png (196.6 KiB)
screenshot-2023-12-24-at-104909.png (196.1 KiB)
screenshot-2023-12-24-at-104926.png (179.9 KiB)
screenshot-2023-12-24-at-105040.png (177.1 KiB)
screenshot-2023-12-24-at-110046.png (198.6 KiB)
screenshot-2023-12-24-at-111858.png (217.6 KiB)
Jason - UK avatar image
Jason - UK answered ·

@Hu2bPV do you have AES turned on in VE.Configure?

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Huub avatar image
Huub answered ·

I'm not on the site so I cannot check. Please help me understand why this may be relevant.

in the meantime the battery is almost full. So the BMS had to limit charging power. and it graciously did: no more trips. Also the ET340 is behaving correctly. Excess power now feed into the grid.

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Huub avatar image
Huub answered ·

best wishes for 2024

just an update:

AES was not turned on


On returning home, there was and sun (PV 2000W) and the electric heater (3000W) was turned on and that led to a total disconnect of the ESS (connection to BMS Pylontech was lost). (in the control panel : ESS blocked)

Yesterday put a USB-3 hub (WLXKJY USB 3.0-Hub) with power supply (36 W)between the USB extension cable and the ET340 connection.

I also connected the AC Current sensor - single phase (CSE000100000) to measure PV production directly.

If it gets a bit sunny over the next few days, I can see if the system continues to behave even when larger loads occur both on the production and consumption side



2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Related Resources

Energy Meter Selection Guide