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lc10w avatar image
lc10w asked

Smart Solar 100/50 panel connecting

Inside my Easysolar1600 is a Smart Solar MPPT 100/50. Currently, I have two 340w panels connected to two of the three sets of MC4 connectors at the base of the Easysolar unit.

Can I connect a third panel, that has a smaller wattage to the others? I only have roof space for a 200w panel. On really sunny summer days I've yeilded over 600w from the 680w of the two panels. On dull winter days, I could do with another panel. I was thinking I could switch in (via a DC solar breaker) a third panel, and isolate it on sunny days, so as not to exceed the MPPT's 700w and 100v maximums.

Can I connect a third panel of a different wattage and voltage, and is the above feasible/doable?

What would happen if I exceeded the unit's maximums, IE forgot to isolate the third panel on a sunny day?


MPPT SmartSolar
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Michelle Konzack avatar image Michelle Konzack commented ·
What is the Voc ofvthevtwi 340Wp panels?

Do you clean them in the Winter from Snow?

I would suggest you to put them in series, because in the Winter it is definitiv an advantage with higher panel voltage


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Alexandra avatar image
Alexandra answered ·

@lc10w

Connecting different wattages together means they will all behave like the smallest panel there. So effectively you will have 600W not 340+340+200 since it will behave like the smaller panel

Since you are connecting in parallel not in series the voltage max will not be a problem.

What is more likely to be a problem is the isc or short circuit maximum for the mppt. So what is the temperature compensated total of the panels ISC?

You would have more benefit and probably be safer with a different small pwm or mppt on the extra panel.


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lc10w avatar image lc10w commented ·
Thanks, a separate MPPT sounds like a plan.
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Michelle Konzack avatar image
Michelle Konzack answered ·

If the Voc is 40V per panel and i assume a temperaturcoefficient of -0,4%/°C, then you can have -30°C in the winter with full sunshine and full batteries without cooking the SmartSolar if you put the psnels in series.

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