Is exceeding the maximum PV input voltage by a little bit okay?

dsdc

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I have a power station with 12-30V PV max input PV voltage.

I also have a used panel with Voc 32.6 and Vmp 25.9. Is it going to be okay for me to plug the panel into the power station directly with it being so slightly over?

Thanks
 

Bud Martin

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I would not try it unless you know for sure that the power station has really good protection for PV input, the VOC will go even higher in cold condition.
 

Jordi

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I would not try it unless you know for sure that the power station has really good protection for PV input, the VOC will go even higher in cold condition.
Very convenient topic. What would you think about a VOC of 57,5V for an MPPT inverter that can not tolerate more than 60VDC? Theoretically at 0*C the VOC could reach the 60V.
 
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chrisski

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I think its a terrible idea to plug that panel in, but if you’d like to experiment, I’d like to hear the results.

Was mentioned how temp can effect panel output. I knew cold would up the voltage, but did not know freezing weather would up it by 20 volts!!

I see higher voltages on my panels when my system and batteries do not need much energy at all. My system also spends most of the time at charged or close to charge. That would mean my PV voltage exceeds the SCC voltage most of the time, and more so the colder it gets.

I have no experience exceeding voltage for an SCC, but generally considered a no-no with the possibility of up In smoke type badness. I was looking at an Amazon review for a 75 volt SCC where the person gave a one star rating because it fried when he put 75 volts of panels in it. To me, that is a bogus review because the voltage of a panel moves around by a few volts and would easily exceed the 75 volts of the SCC. That SCC went up in smoke.
 

HRTKD

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I have a power station with 12-30V PV max input PV voltage.

I also have a used panel with Voc 32.6 and Vmp 25.9. Is it going to be okay for me to plug the panel into the power station directly with it being so slightly over?

Thanks

Be sure to post the results in this subforum of the site:

 

RCinFLA

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A MPPT charge controller may check the open circuit PV input voltage and not allow the SCC DC-DC converter to turn on if it determines Voc on input is too high.

Breakdown voltage on switching MOSFET's is rated for repetitive switching. They will take higher voltage when turned off which is why SCC checks input voltage before it begins switching.

There is usually also some switching overshoot ringing that subjects MOSFET to a bit higher voltage than Voc. This should be already factored into the SCC max input voltage check.

Low cost MPPT charge controllers may not check max input voltage. They just let you burn them out if input voltage is too high.,
 

dsdc

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Well with everyone's input, I think I might just go get a charge controller then. Seems like its a disaster waiting to happen
 

curiouscarbon

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may i ask, what model name power station?

with the goal zero lithium 3000 i uninstalled their charge controller (only like 20V max input) and replaced it with a victron mppt with muuch higher max input voltage rating (100V) and it worked great. felt so good to safely connect two 300W panels in series to charge that power station.

very important to research the power station’s battery cell chemistry max and min voltage and program the solar charge controller according to that
 

Hedges

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Well with everyone's input, I think I might just go get a charge controller then. Seems like its a disaster waiting to happen

Just get a different PV panel.
There are "12V" panels with Vmp around 17 to 18V, Voc around 20 to 22V.

There is probably also a max Isc spec for your device.
Does it contain a PWM (rather than MPPT) charge controller?
 

dsdc

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Nov 25, 2021
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I did try this a few days ago with a lower setup though, I think the power station was rated for 6
may i ask, what model name power station?

with the goal zero lithium 3000 i uninstalled their charge controller (only like 20V max input) and replaced it with a victron mppt with muuch higher max input voltage rating (100V) and it worked great. felt so good to safely connect two 300W panels in series to charge that power station.

very important to research the power station’s battery cell chemistry max and min voltage and program the solar charge controller according to that
Of course, it's the Bullbat Pioneer 500. The spec says 12-30V input and 160W max
 
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