DiyBMS V4 (ESP8266) controller reboot

Hardware diyBMS
1

Hello everyone (and Stuart specifically) … I have installed a 16s LFP system with v.4.21 modules and use the relays on the (ESP8266) controller to manage the contactor which cuts off the battery in case of issues.
I have noticed that (usually at night, like 1AM or 5AM) when the loads are really low, sometimes the controller reboots every minute for 10 to 20 minutes, which cuts off the relay … the battery, and in the end the inverter (Victron Multiplus) either goes to “Passtru” or even shuts down because it thinks the battery is low.
I have moved the controller away from the cells (originally it was on top of the cells - separated by a PMMA sheet of plastic (see picture) as I wanted to keep TX/RX as short as possible.

camphoto_1812494366
camphoto_18124943661920×1440 274 KB

I changed the generic ESP to a LOLIN D1, changed the controller (had another one), soldered the relay board to the controller outputs, changed the DC source to a more powerful one … and moved the controller away, so now the TX/RX cables are longer… but to no avail.
This night again, the controller decide to reboot during 10 minutes …
I will try to add more ferrites to the cables to see if it is due to interference, but I really doubt it, because I noticed that interference is usually at high charge/load rates, when the controller loses communication. In this case the loads at night are reallly low.

Can somebody tell me what else I should check and/or improve ?

2

@Gregory_Fierens I too have had this problem for a while, what I have worked is if the controller reboots while it’s powering on it will activate the relays, also if you have a large bank like mine 14S3P it takes several seconds for all the modules to report in and so the BMS will only calculate the voltage on the modules that are avalialbe and obviously triger the low pack realy and trip the shunt. I have also noticed that sometimes while keeping the web page to the BMS open for periods the controller either reboot or trip the relay.
I have looked for some sort of delay relay cuircuit that the relay activats and has to keep open for 5-10s in order for that delay relay to trip the shunt.
Still today I don’t have a soloution, it’s intermittent and only a couple time a month, so I have learnt to live with it.