Questions for my New Solar Shed Project

I’ve started collecting and processing 18650 cells that I will be integrating into a 7S##P battery in my solar shed project that that will be based around a MPP Solar LV2424. Any feedback on my design below would be much appreciated.


I like the idea of building a DIYBMS, but this is not an all in one solution. I do have some outstanding questions regarding this type of solution:

  • From what I can tell I would need to either add some sort of battery disconnect controlled by DIYBMS (shunt trip, contactor, other?) to shut off the battery in case of a problem. What is the best/most efficient way to do this?
  • Do I need to add some sort of disconnect to the solar panels as well? or will the MPP take care of this?
  • Do I really need a shunt to measure battery current? What if I omit this?
  • Are there any thing else I need to consider for integrating a DIYBMS?

Thank you all in advance for any feedback.
Mike

If you use the ESP32 CONTROLLER you may switch Relais when a problem appears.
Also a large one which could disconnect the battery.

The MPPT will normally not take care. If you need or not… Up to you.

No. Depending on the inverter this one may also measure current.
If you work completely without current measurement you can’t regulate the charge.
Especially if the BMS detects a high voltage in one cell.

It’s a passive BMS. If a cell gets over voltage energie will be burnt. Not transferred.
If the cells are well balanced it works. If not you are a little in trouble to synchronize.
I have the case because I was to stupid to initialize the cells good enough before using.
It took me 2 weeks to synchronize from 250mv difference to 20mv.

Thanks for the reply, greatly appreciated. I was planning on going with the ESP32 as it offers more.