output power today is astronomical

lamplight

I am watching 850 - 891w watts from power output from my 875w sharp array (a paralleled, at 24v), its 11am, not near solar noon, its quite cool in the upper 40's.
using morningstar's tristar mppt 60

this is the output power, the sweep pmax is 759 watts

it is partly coudy so theres some edge of cloud issues going on too, but ive been watching how the sun will be out for 3-4 minutes with a sustained power output in the 830+ range

i can't be sure but i thnk the tristar responds quicker to changing conditions that my mx60 did.

as some of you know i have a battery bank being delivered (tomorrow!! that my array is slightly undersized for so i will probably be adding another panel and rewiring the array for 48v. i seem to recall my mx60 did better mppt at 48v than 24v.


-
WOW!!

Solar Guppy

Re: output power today is astronomical

Two comments, 15-30% edge of cloud boost is normal , usually only lasts a few minutes at most

The sweep reported pmax is at best an estimate, the input current for the TriStar Mppt can be off ~30% at times ( uses the resistance of the fets as the shunt ) ... its very accurate to find the vmp on the sweep, but its only used as a relative value to find the mpp, so don't bother trying to figure things like panel harvest or the units efficiency from that.

solar_dave

Re: output power today is astronomical

Solar Guppy wrote: »

Two comments, 15-30% edge of cloud boost is normal , usually only lasts a few minutes at most

I am sure this has been explained some place here. Links to threads?

BB.

Re: output power today is astronomical

I am guessing that this has to do with a combination of ice crystals in the atmosphere concentrating more light (22 degree primary refraction angle), and bright sun through a hole in the could and thin/high clouds reflecting and diffusing additional sunlight. Plus, you may get a bump in output with cool panels and bright sun (panels will quickly heat up).

From what little I could find with a quick search--people seem to associate the reflective nature of clouds as the dominate effect.

Sun dog - Wikipedia
www.atoptics.co.uk/halosim.htm

-Bill

icarus

Re: output power today is astronomical

Gotta love those edge of clouds.

Summer here is full of puffy cumulous clouds,, high output events,,, sort of off set by the clouds themselves.

Tony

mike95490

Re: output power today is astronomical

Also check out Cloud Glory and a couple pics I took :
http://forum.solar-electric.com/showthread.php?p=25841&highlight=lensing#post25841

lamplight

Re: output power today is astronomical

you make more and more sense every day


thanks! new panel is on it's way. (its killing me the shipping costs!! if only i'd known earlier in spring what i was going to do i could have orered both at the same time and save a couple hundred in shipping).

lamplight

Re: output power today is astronomical

Solar Guppy wrote: »

The sweep reported pmax is at best an estimate, the input current for the TriStar Mppt can be off ~30% at times

I'll say!! now that i have my trimetic monitor on there i am shocked at how off it can be. whats the point almost??! I have yet to determine (with time) if it is off in a consistent range which it sounds like you're saying is not the case in different weather scenarios.

OH BTW - the above post was in response to an entirely different thread i have no clue on how i posted it here.. . was probably one of my late night coffee induced delerium

russ

Re: output power today is astronomical

The manual for my Davis weather station says that high cirrus clouds can cause high solar readings but my observations are like Tony's - seems that the fluffy cunulus clouds cause more distortion under certain circumstances.