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mianfrar asked

Mppt 150/70 clip power without shadows

I have a Mppt 150/70 with 3 series of 3 panels of 330w and all connected to a cerbo and multiplus II 3kw 48v with batteries and bms, configured ESS. There is also a Fronius primo connected in cin.

The fact is that every day around 3:00 p.m. there is a drop in production as if it had a shadow but this does not exist, verified, it coincides with a current close to 28a coming from the panels and 40a towards the battery. The cut occurs at 40a +-0.1a, can this be related? Is there some kind of mppt curve programming in the equipment that changes at 40a?


MPPT Controllers
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2 Answers
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Mike Dorsett answered ·

Try checking the internal temperature of the MPPT - or if you don't have access to this data measure the heatsink temperature. If it is hot to the touch - or above 60C, then add a cooling fan, MPPT's have an internal temperature limit, and generally insufficient natural cooling if mounted flat to a wall. Adding a spacer or a small fan helps enormously at high power levels.

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mianfrar answered ·

Thank you, I have blown it with an air compressor for about 5 minutes and it does not affect production, so I almost rule out that the reason is temperature

The inverter is the multiplus II from 3kw to 48v configured to inject excess DC, could it be that with the battery charged the maximum production of the mppt is limited to protect itself against a grid failure?

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