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Hi.
I have an easy solar 48/5000/70 with the 150/100 mppt.
I.m looking at configuring my panels on a static boat roof.
6 face south, 6 north, and I can place 4 on an east facing roof.
I have noticed the max voltage of these panels on another system reach 50.1 volts, so I can only safely series them in pairs.
Are the 3 pairs of mc4 connectors in the easysolar unit 3 individual and separate mppts, suitable for different aspect strings, or do they all go into just one mppt?
Thanks, Steve.
Hi @stevla
The 3 pairs of MC4's join together within the unit to one tracker. They exist that way because the MC4 fittings are only rated to 30A and the unit can handle a total of 70A from the pv.
Surprised you can't get 3x in a string, but there's a calculator you can use to check the string suitability.. https://mppt.victronenergy.com/#
Try to keep all your panels of the same specs with so many strings. Having them facing different directions isn't ideal, but should still be ok, especially if you can keep the sun on them all at once.
Thanks John.woukd you suggest series 3 on South, and parallel to 3 on North and so on? ..the calculation agrees that I can series 3 up at a time.. cheers Steve.
Good you can get them into 3x panel strings.
Yeh, best mounted with each string as a 'block' in the same direction, and parallel each in. This isn't the perfect way to do it, but you've no choice with one mppt. What you may find useful is to have separate isolators for each direction to be able to detect if the mpp of each string is far apart and excessively hindering output. You'd need to be patient doing this, as the mppt tracks only every 10 minutes. I've found that the mpp's remain close, providing the panels have direct sun but even with different sun angles on them. Shade is another story, but the single tracker will do it's best to optimize them as a group anyway.
you could use a big blocking diode in series with a string of 3 panels, this would give you a 0.45V drop - you lose some power, but it does add some protection. Check the Voc of the modules from the manufacturer's data, and remember to allow for cold operation as the voltage rises when colder than 25C.
Hi Guys, I've been trying to learn how to make a solar MPPT for battery charging application. I'm still a bit unclear how the MPPT changes the output voltage of the solar panel by varying the duty cycle. Can anyone shed some light on this for me? :)
