MPPT & Multiplus max power during grid feed in

DIY
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1

I have a 24/2000/50 MP and a 250/70 MPPT. Solar is quite over panelled.
All connected to a a Cerbo with ESS.

I have set my grid point to -1500W to stay below the MP limit.
I thought to test if my MP regulates this and set my grid feed in to -2000W. This is the max the MPPT is able to deliver in a 24V system.

Question:
Should I ‘protect’ my MP by setting a safe grid feed in maximum? Or can I just set it to -2000W (or higher) as the MP will regulate this himself?

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Seems like it delivers the full 2000W.
For the time being I’ve set it back to -1500.

Edit: I realised I asked a similar question a month ago. Forgot about that.

Maybe just need some assurance before setting the power to unlimited.

What’s the experience of others with grid feedin? Does is exceed the W rating of the MP?

2

The multiplus is rated 1600W and cannot produce more power irrespective of your solar and neither can the MPPT produce more power that what it is designed for. The MPPT will limit its output current in the event of oversized arrays, as long as the input voltage is respected which could damage the mppt if exceeded. More importantly, power is only produced to serve a load so the inverter can only ever call on max 1600W from the MPPT (not accounting for losses and other factors) and the MPPT will produce 1600W. It can be higher if PV DC power is used to charge the battery at the same time the inverter consuming 1600W, again only up to its 2000W rating of the MPPT.

3

MPPT Voc and Isc are well below limits.

Thanks for your reply and assurance. I forgot that there are significant losses while operating at the max power of the MP. 2000W PV results in around 1600W exiting the MP.

After retesting it went up to the maximum of 2000W PV generated. 1950W send to the MP. 1600W being used/fed in to the grid. Battery was idle as it was in float at 100%. Efficiency was only around 80%.