EV Charger Disconnecting - Node Red Implementation?

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nathan-skelly asked Apr 28, '24

EV Charger Disconnecting - Node Red Implementation?

Hi There,

I've been playing around with Node Red to come up with a control logic for running the EV charger in an off grid situation. What I want to understand is whether there is a best practice in how you manage the messages to the charger?

The reason for my question, is since using the Node Red automation, I seem to have the EV station disconnecting very frequently, requiring me to switch it off at the switch board and back on to reset it.

I get correlation =/= causation, but it seems a touch convenient that it happens now.

Is there a best practice on how to do this? I've never coded before so this is all a learning experience for me, and Chat GPT only gets me so far.

Node-RED Modbus TCP ev charging station evcs

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Answer 1 · 2024-04-29T10:13:13Z

matt1309 answered · Apr 29 at 10:13 AM

Hi @Nathan Skelly

When you say disconnect do you mean fully crash/is unreachable via wifi? Or do you just mean the node goes offline for a period of time? ie could it be that the unit has always been disconnecting and reconnecting (maybe due to weak wifi) and you're just noticing it now because it's connected to node red and checking the status of the node?

Or by disconnecting do you mean the unit disconnects and never reconnects? Almost like it's crashed (if that's the case I'm not too sure, you could maybe share the automation code and someone might be able to spot something that is causing the EVCS to crash or have an issue.

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nathan-skelly commented · Apr 29 at 10:54 AM

Hi @matt1309

Disconnects as in seemingly loses power/shut down and needs a hard reset. It shows as disconnected from the CerboGX, and I can't connect to it via bluetooth using VictronConnect either. The light ring around it is off, and the only way it seems to come back on is to turn it off at the switch board and back on.

My wifi is in the garage with the charger, so definitely not a range problem.

I'm not sure how to share the code, it far exceeds that character limit here.

This is the flow. It has 3 different charging modes running through. Outputting a 1 or 0 to turn the charger on or off, filtered so only sending 1 message (in theory)

Then dynamically adjusting the amps based on 3 different targets depending on the charging mode that is operating. Again sends one message filtered to when it changes.

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matt1309 nathan-skelly commented · Apr 29 at 11:04 AM

I'm not too sure then sorry. I was going to ask are you writing directly to modbus and maybe there was some sort of issue with writing to the wrong register and causing the unit to crash but appears you're using the actual EVCS node so it wont be any rogue modbus postings.

I'm not too sure how the code/firmware works on EVCS side to guess if there's an obvious thing that might crash it, my next guess was going to be maybe sending data too quickly to the unit, but i imagine they'll have coded it such that it wont be impacted by that.

Is there a length of time it tends to last before crashing?

My only suggestion is setting up some sort of logging system. So you can see what node red sends to the EVCS and at what time you're sending it before it crashes.

Maybe adding in a function that comes off the last but one node with something that write's msg and timestamp to file. And another node/flow that detects if evcs node goes offline to record when the crash occurs.

Then see if you can spot a message or something that you send from node red to the unit that triggers it.

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