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tazer asked

Custom ESS, MPPTs not charging if inverters are in passthru

I've written my own ESS logic as a Python script. Everything works as expected, except one thing: When the batteries are depleted at night, my inverters correctly go into passthru mode, but when the sun comes up in the morning, the MPPTs stay off and don't recharge the batteries. The whole system stays off and never turns on again. I have to set it to "Optimized" in the VRM portal and back to "External" to get it back up and running.

Anyone has an idea what flag needs to be set to get the MPPTs to charge even if the inverters are in passthru? Attached you find my current prototype: dbus-custom-ess.zip

WARNING: This script is tailored to my specific setup and will not work on most systems! It's a starting point for anyone interested in doing their own custom control loop, but far from finished or ready for general use!

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dbus-custom-ess.zip (3.3 KiB)
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1 Answer
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tazer answered ·

I think I found the cause: As noted, the Multis go into "Passthru". This mode implicitly disables charging and discharging, ignoring "/Hub4/DisableCharge".

That seems to also affect the MPPTs. With charging disabled, they won't do anything until the inverters start up again, causing a deadlock (no inverters -> no charging -> no power -> no inverters). I modified my script to send a setpoint of 0 periodically and set "/Hub4/DisableFeedIn" to disable the inverters. This has the same effect as previously, but the Bulk LED stays on.

The system restarted correctly today, all four MPPTs are charging. So the issue is resolved, I will leave it here if anyone has that problem in the future.

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