Battery and PCS MPU

[misraa]

I'm trying to add some batteries and backup and I'm confused about PCS main panel upgrade avoidance.

Let's say I have 20a of solar and 1 5P at 20a. That's fine to back feed at the max 40a into my 200a main panel right? But don't people usually have over that making MPU usually needed?

Because I'll have probably have 2 batteries at 40a and backfeed breaker will need to be 60a or am I wrong?

My main concern is moving consumption CTs from the main panel to the system controller and losing whole home consumption monitoring? What do people usually do?

Should I derate my panel? Or use oversubscription to limit 2 batteries to 20a?

[Manon_Chaboud · Accepted solution]

Hello @misraa !

It sounds like you're considering adding batteries and backup to your solar system. If you're planning to add more batteries and increase the backfeed amperage, it may indeed require an upgrade to the PCS main panel to handle the increased capacity. Moving consumption CTs from the main panel to the system controller may affect whole home consumption monitoring, so it's important to consider the implications.

In such cases, some people choose to derate their panel, while others use oversubscription to limit the battery output. It's essential to carefully assess your specific requirements and consult with a professional to ensure a safe and compliant setup. Every installation can have its unique considerations, and professional advice can help navigate these decisions effectively.