What are the dangers of 200w of solar through a 165w mppt please?

[MisterB]

What are the dangers of 200w of solar through a 165w mppt please?

would it be an issue re safety, or just be an issue in not getting the full amount of power being produced?

i have a Votronic duo Mpp 165 and am trying to source solar panels that will fit in the spaces i have available - which isnt a lot, so i am having to go for 2 separate panels. i want to get the maximum amount of solar i can get on the roof but dont want to do anything that is unsafe.

My thought process is that if i ever upgrade my MPPT then i can harness the additional power being produced without changing the panels, what i dont want to do however is 'blow up' or damage the MPPT or any wiring - which will be inside the van.

Thanks

 

[Abacist]

Why not buy another controller and have one per panel? Don’t like the idea of overloading the controller as you might cook your batteries if the controller is damaged and can no longer control the output from the panels, then there would be a fire risk!
Not an expert, merely projecting what might or could happen!

This is set up I have for 2 panels and 2 MPPT controllers.

 

[MisterB]

thanks, having another controller was something i was considering, until i eventually get just one controller to do everything, can you mix an mppt regulated set up with a pwm regulated setup?

do you just have both systems feeding into your battery bank?

 

[Abacist]

MPPT controllers are best so I would not get a PWM to go with your MPPT one. In my system both controllers feed the same battery bank via a fuse box which means you can then disconnect the batteries from the controllers without disconnecting the controllers themselves or covering the solar panels. By having 2 controllers you will be sure that if one panel is in partial or total shade the other will still give you your charge. I also experienced one faulty controller so the other kept me going but I would have been stuffed with only one controller.

 

[Jamesh]

Not in the north....!

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[68c]

Unless your van is parked near the equator at noon it is very unlikely it will actually produce 200Watts. Here in the more northern latitudes with a panel flat on your roof I am sure it is safe to use the 165Watt controller.

 

[paddymcc]

Unless your van is parked near the equator at noon it is very unlikely it will actually produce 200Watts. Here in the more northern latitudes with a panel flat on your roof I am sure it is safe to use the 165Watt controller.

I believe the Votronic controller will limit the output to it's maximum if you did actually get 200W out of the panels but as 68c says that's unlike in the UK. If you went to S Spain in summer you could have the option of disconnecting one of the panels?

 

[Lenny HB]

Although Victron controllers can handle excess solar without a problem Votronic do not recommend it.

I would just fit a second MPP 165 controller then you know its all going to work properly without any probems.

 

[pappajohn]

If you fit fuses put them between panel and controller as well as between controller and battery.
Modern controllers need to see a battery voltage before the solar panel is connected so the controller knows what voltage to work on.

 

[autorouter]

What are the dangers of 200w of solar through a 165w mppt please?

If the panels are horizontal on the roof (ie not tilted towards the sun) then you are unlikely to get more than 80% of the full rated output, so should be fine. The 165W is a 'soft' limit, and the MPPT will just waste the excess power that it can't use. Obviously within limits, but 200W should be fine.

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[BobJayne]

If the panels are horizontal on the roof (ie not tilted towards the sun) then you are unlikely to get more than 80% of the full rated output, so should be fine.

Is this another use for carrying two ramps (from another post), to get a more efficient angle for your solar panels!