question

pekkaj avatar image
pekkaj asked

Overpowering MPPT

What happens to MPPT if it receives more than rated max solar power (amps and/or voltage)?

MPPT SmartSolar
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5 Answers
ejrossouw avatar image
ejrossouw answered ·

It will almost certainly fail and is not covered by the warranty. Ensure you size the panels correctly using the available tools and take into account the input voltage at all temperatures, ensuring it always remains within the specified operating parameters of the device. No components are serviceable so not sure why you would ask the question?

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kevgermany avatar image
kevgermany answered ·

Voltage is the killer. The MPPT controls the amps. Except for lightning and short circuits. So don't exceed the Isc rating of the MPPT in your panel setup.

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Michelle Konzack avatar image
Michelle Konzack answered ·

Generally the Wp do not realy matter.


As long as you do not exceed the maximzm Voc in a cold sunny winter day, you can put even 5600Wp modules on a SmartSolar MPPT 250/100 with only a 24V battery. The SmartSolar simply limit the output current to 100A or rate ircdown it it become too hot.


On the PV side you will onky see an enormous Voltage increase, because the SmartSolar simply can not take the whole energy.


However, the over powered SmartSolar has then an advantage in the Winter.

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pekkaj avatar image
pekkaj answered ·

Thanks for all the replys! Just wanted to be sure about the voltage. It would be nice to have more panels from autumn to early spring, but it would then require some kind of switch to be able to disconnect additional panels for peak solar season.

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Alexandra avatar image Alexandra ♦ commented ·
You can add more strings up to max amperage. That takes care of low light conditions.
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kevgermany avatar image kevgermany ♦♦ commented ·
As @Alexandra said.

Your existing panels should have solar isolator switches. Same for extra strings. Make sure all strings identical. Don't turn the switches while charging. Wait until night.


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pekkaj avatar image pekkaj kevgermany ♦♦ commented ·

I have 2 panels now and space for one more, so doubling doesn't work...

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aaron-pe4a avatar image
aaron-pe4a answered ·

Victron actually recommends oversizing the solar array with relation to the charge controller due to the fact that you will almost never be charging at the peak power output of the modules. However you must never exceed the maximum voltage rating of a charge controller and the maximum input current rating. For example the charge controller 150|35 blue/smart solar has a maximum of 150 volts DC input. If the voltage exceeds 150VDC you will almost certainly damage the controller permanently. In the datasheet Victron mentions this and it also shows a maximum input current of 40A that would also damage the controller if exceeded. So never exceed 150V and 40A input for the 150|35 controller. Victron also has an excel sheet that helps you calculate this on their website at the bottom of this page. You input your solar modules parameters and it will tell you if your configuration is acceptable for the chosen controller.


hope this helped!


Aaron

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aaron-pe4a avatar image aaron-pe4a commented ·

here is the page, not sure why my hyperlink didnt work


https://www.victronenergy.com/support-and-downloads/software

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