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mojo avatar image
mojo asked

Smart solar mppt 150/35

Hi I’ve had 3 Panasonic 245w solar panels fitted. voltage Vmpp 44.3 ,voltage Voc 53v. I also bought a smart solar 150/35 mppt at the same time as I was was advised by the retailer that this would be suitable for the panels. I also told him the panels would be wired in series. All to be fitted on a narrowboat.

To cut a long story short my installer connected them on a very bright sunny morning. As a result the smart solar app soon showed an over voltage of 153.81v

Obviously this is higher than the rating of the mppt . Now the the blue led is flashing every 3 or 4 seconds. And it’s not charging the batteries. I’ve also disconnected one of the panels to bring the voltage down but this hasn’t made any difference to the led status. Looking at the manual this indicates an internal error, fuse blown?

So my question is have i interpreted the fault correctly and is it repairable? Just looking for confirmation of my thoughts before I send it victron for possible repair.

I will be re- wiring the panels in parallel to bring the voltage down as spending more on a bigger mppt seems like over kill for my installation

Many thanks Pete

MPPT Controllers
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2 Answers
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wkirby answered ·

Hi Pete

Your retailer has ill advised you. It seems they neglected simple mathematics, 53x3 = 159V. This is of course well outside of the 150V maximum. In colder conditions this Voltage will be even higher.

It is highly likely that his over Voltage condition has blown the transistors in the front end of the MPPT. The 150V maximum is a hard limit not to be exceeded. It is the transistors that dictate this maximum limit.
Wiring you panels in parallel would bring the Voltage way within the specifications for that controller. I don't know what your battery Voltage is, 12V or 24V would be fine with all panels in parallel.

Since the retailer issued poor guidance I'd return the MPPT to them and request a replacement.

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mojo answered ·

Thank you for your swift reply. My system is 24 v.

My other query is in the event my supplier won’t replace the item would it be repairable by victron ?

Pete



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