Hi all
I'm victron installer. I recently (yesterday) installed the victron EVCS in an off grid plant, and I found a very weird bug that cause the evcs in auto mode to stay locked in the "waiting for sun" state.
Lest explain a bit the situation, and what I suspect to be the exact source of the problem.
The system is composed by a cerboGX, multiplus II 48/5000, one 150/60 mppt with 2600Wc PV on it, other 2500Wc PV plan AC coupled with a Solis inverter (wich work nicely with frequency shift ! ), two 10kWh PAND PowerCube lithium batteries, and the EvCS feeding power to a Renault ZOE.
I configured the EVCS for start charging when SOC reach 100%, and stop at 97%, to be sure most of the capacity remains available for the house.
I waited to see how it works, and... nothing. When the battery was fully charged, the evcs status goes from "low SOC" to "waiting for sun", whereas it was a fully clear wheather, at 11AM...
And then the house's water pump started, so some energy was drawn from the batteries during the time the mppt and the Solis inverter restarted, and when they started to produce power again, thus refilling a little bit the batteries, evcs started to charge.
Wow, that was strange.
So I investigated a bit, and found the "waiting for sun" state is waiting for the battery current to be positive (but I can't determine the trigger level) to detect there is sun power available.
Then it starts a 30s delay, and then if the current is still positive, it starts charging.
I think when using lead-acid batteries, this works well as when it switches to float, there still be a small current feeding the batteries. But whith lithium ones, as the current abrutly goes to 0 when the BMS say they are fully charged, it won't.
I tried to change the SOC start settings to 99% to see what happens. Same thing, as I suspect it waits the SOC to be above the setting and not just reach the setting.
Setting a lower starting point works as expected, as the battery current is still positive. But then the battery never reach 100% if the car can't be fully charged by the end of the day.
I think to solve the issue, it's needed to remove or at least *make configurable the starting delay* when sun is "detected", as 30s is way too long is this situation.
And also when the SOC is 99 or 100%, allow to start charging when battery current is *not negative* instead of *positive*
Anyway, great job with this evcs, when it starts, then it adapts nicely to the available sun power :) but I'd love the current change to be a little faster. Can the adaptation speed become configurable also ? Would be great ! :)
Also something wich would be really great to investigates would be to have a VRM widget with the evcs state and another with the wanted/effective charging current.
I have some C/C++ programming skills, I already played with ESP32, so I think I can help with this for free if needed :) I would love the have my customers happy with the devices I install :)
