I think I have ironed out a disconnect / safety strategy with my hybrid setup, Sol-Ark 12k.
Goal is to trigger a relay via BMS (Batrium) when either cell voltage is too high, low or a single cell starts to fail based on relative voltage delta.
Today my system is setup to do "grid zero" via limited to home as long as I have PV / Bat. capacity to meet my household loads and if loads exceed system setup then the grid supplies the short fall.
The challenge is two fold after confirming with Sol-Ark
1 - Damaging the inverter if you disconnect the battery under a load. Sol-Ark confirmed that using a relay to disconnect the battery is a "no no". If there is any significant load (they are unable to define significant) then having an emergency disconnect (breaker) could damage the inverter.
2 - The built in RSD relay is only for PV (mppt controllers) and does not shut down the inverter. I was hoping it would shut down everything but the main purpose is to just meet 2017 code for panel level shutdown.
Soo here is my thinking on how to tackle the scenarios...
1. High voltage scenario or Large cell voltage delta -need to stop any charging taking place so I would leverage RSD via relay from the BMS. This would kill any charge and allow the batteries to drain down with existing loads. I would have to manually reset the RSD though I think (Sol-Ark was not clear on how to reset).
2. Low voltage scenario or Large cell voltage delta - 4 pole shunt trip breaker (ex. ABB s5n) on the AC side. This scenario would also require a manual reset but it would kill any inverter demand and as such allow the batteries to charge if there is PV.
I think I am covered and outside of the inverter failing the high and low scenario should never take place given the limits I have set within the inverter. The real benefit or coverage would be for a large cell delta.
Thoughts?
What are others doing given the Sol-Ark limits?
Thanks
Goal is to trigger a relay via BMS (Batrium) when either cell voltage is too high, low or a single cell starts to fail based on relative voltage delta.
Today my system is setup to do "grid zero" via limited to home as long as I have PV / Bat. capacity to meet my household loads and if loads exceed system setup then the grid supplies the short fall.
The challenge is two fold after confirming with Sol-Ark
1 - Damaging the inverter if you disconnect the battery under a load. Sol-Ark confirmed that using a relay to disconnect the battery is a "no no". If there is any significant load (they are unable to define significant) then having an emergency disconnect (breaker) could damage the inverter.
2 - The built in RSD relay is only for PV (mppt controllers) and does not shut down the inverter. I was hoping it would shut down everything but the main purpose is to just meet 2017 code for panel level shutdown.
Soo here is my thinking on how to tackle the scenarios...
1. High voltage scenario or Large cell voltage delta -need to stop any charging taking place so I would leverage RSD via relay from the BMS. This would kill any charge and allow the batteries to drain down with existing loads. I would have to manually reset the RSD though I think (Sol-Ark was not clear on how to reset).
2. Low voltage scenario or Large cell voltage delta - 4 pole shunt trip breaker (ex. ABB s5n) on the AC side. This scenario would also require a manual reset but it would kill any inverter demand and as such allow the batteries to charge if there is PV.
I think I am covered and outside of the inverter failing the high and low scenario should never take place given the limits I have set within the inverter. The real benefit or coverage would be for a large cell delta.
Thoughts?
What are others doing given the Sol-Ark limits?
Thanks