lawrosa wrote:
Thank you all.. I find it interesting.. I its more clear to me now..
Now the two controllers I was considering was the renogy rover 40 amp mppt and the tracer a series 40 amp mppt..
These both list 100 v max But both list 520 watts as max rated power. I doubt I will be over this but technically I could be with two panels 560 watts..
The renogy says nothing about going over..
here..
https://www.renogy.com/template/files/Manuals/RNG-CTRL-RVR2040%20V1.5.pdf
But page 9 of the tracer says you can go up to 3 times over rated power or 1560 watts..
I take this as being I can put 4 panels? Two in series and then parrellel the two?
Im sure I will not need to do this and should get sufficient amps with just the two panels..
http://www.epsolarpv.com/en/uploads/news/201710/1508812885787574.pdf
So my budget is about $200 bucks... I only need a controller..
Other then what I posted for my choice is there another I should look at?
Renogy has #8 lugs, Tracer has #6 lugs...
I also know I need the MT50 with tracer or pc adapter with renogy.. ( I heard the lugs on renogy are junk as you cant get the wires tight...
I will probably keep the eco worthy in place and use it for when I put flex panels on roof eventually.
Example e bay has theses 320 watt 24 volt flex panels for 139$. I have the hard panels to put up there but the rack system would mean me drilling holes in roof, and Im not sure I want to do that. And those panels weight 50 lbs each. The flex would be easier for me to install with durabond tape.
https://www.ebay.com/i/311774906772?rt=nc
This is a future project with roof mounts, but for right now I want to utilize another panel and use as a portable.. even though they are large to lug around.. lol...
with 560 watt panels I doubt you will EVER hit the 500W max, let alone exceed it. And even if you do it normally is not an issue for the controller. It will just limit the output and you will waste some power.
as panel temps go above 25C panel voltage drops, typical panel output drops about 0.5 percent/C and a 20C rise in the summer is not out of the question.
panel voltage drops about 2.2mv/C for each cell. Current rises slightly with higher temps, but very slightly. something like 0.001 percent/C
A 90F hot summer day with no breeze and lots of sun can have a very noticeable effect on panel output.
A cold clear winter day another story.
A more realistic number is something near 400-450 Watts.
To hit the 560Max, you need an absolutely clear sky, no humidity, perfect aim at the sun AND keep the panels at 25C.
More and more panels are listing the max per the defined spec's, which are almost impossible to ever meet, along with a more accurate output based on a more typical energy density/sq foot from sun radiation and a more typical actual panel temperature.
That number is IIRC around 80 percent of the ideal max panels are rated at.I have 3 portable 160W panels and 3 fixed horizontal 160W panels.
On the portables under optimum conditions with proper aiming I have seen 375W output into a well discharged battery bank. Now during the peak reading we did have haze from forest fires which even when almost not visible has a noticeable effect on output.
on the horizontal panels 250 is the best I've seen since I can't orient them and it was fall at northern latitude. now in the spring or early summer I suspect it will go up some.
