I currently am running 10 - 210 watt 12 volt 11.8 amp Evergreen panels which are in a 24 volt series coming in to Classic 150 with 24 volt battery system. I just received 10 - 235 watt 24 volt 7.8 amp Sharp panels and would like to know the best way to connect them. Please keep in mind that my 10 Evergreen give my plenty of power during the summer but the winter months the sun is coming thru trees and I go from 10 KW daily summer to 0.5 to 2 KW a day winter. So the new sharp will be just for winter months or cloudy and rainy days. Yes the trees have to stay.
Thanks
Mike
Hi Mike,
What are the Voc and Vmp of each panel type? Are the amps you list the Imps for each panel?
With this info we can determine the possible array layouts. With 4450 watts of panels you willl need to get a second Classic 150 or move to a 48volt battery system in order to not max out the classics current output capability .
mtdoc, thanks for the reply, as I mentioned in my original post, these extra panels are only for the winter. My 150 is set to max out at 85 amps.
Sharp
VMP 30
IMP 7.81
Watt 235
Evergreen
VMP 15
IMP 11.6
Watt 210
Ok, in simple terms......
Can I take 2 of my Evergreens (VMP 15, IMP 11.6 watt 210) have them in series for VMP 30 (24 volt system) and then parallel them with my new Sharp (VMP 30, IMP 7.81 watt 235 panels)?
Please keep in mind that the sun currently is shining through my trees so my power is about 1/5th that it is during the summer. So I am just trying to give me more Kw per day through the winter months, which I am down to .2 to 1.5 Kw per day. during the summer I get 5 to 10 Kw per day.
Quote from: mtfalk64 on October 31, 2012, 09:53:42 PM
Can I take 2 of my Evergreens (VMP 15, IMP 11.6 watt 210) have them in series for VMP 30 (24 volt system) and then parallel them with my new Sharp (VMP 30, IMP 7.81 watt 235 panels)?
Yes. When you put panels in series the Imp must be close. When you put them in parallel the Vmp must be close. Your proposal should work fine.
--vtMaps
As vtmaps says - panel strings in parallel need to have VMPs that are close.
Quote from: mtfalk64 on October 31, 2012, 07:09:54 PM
Sharp
VMP 30
IMP 7.81
Watt 235
Evergreen
VMP 15
IMP 11.6
Watt 210
Vmp of 15? That is a strange Vmp. Are you sure?. 12 Volt panels usually have a Vmp of around 17. 15 would be too low for reliably charging a 12 volt system.
Also - panels with a Vmp of 30 are not really 24 volt panels (which need a Vmp of 35 or so). Panels with a Vmp of 30 are very commonly used for batteryless grid tie systems and now thanks to MPPT contollers, can be used for battery based systems as well.
So to use panels with a Vmp of 30 to charge a 24 volt battery you would want to have at least 2 in series per each string. For panels with a Vmp of 15 you could get by with as few as 3 per string- but would need 4 per string to match the voltage of a string with 2 of your 30 Vmp panels
So based on the numbers you give, and since you have 10 of each type of panel, I would suggest 2 strings with 4 panels each of your 210 watt panels paralleled with 5 strings of 2 panels each of your 235 watt panels.
You'll be left with 2 of the smaller panels unused.
You'll have a total of 4030 watts of panels. For a 24 volt system this could put out 168 amps - requiring 2 Classics to make full use of. But - as you say, you could limit the output of your one Classic to 85 amps and make use of all your panels in poor light conditions.
If it was me, I'd get a second Classic so that when the sun does come out from behind those trees I could makes use of all that power! 8)
clarify this if you will,
are you using the pvs in a 24v configuration? if so, why not put more in series to raise the voltage? you do know that using more than 2 strings of pvs necessitates fusing/breakers?
Quote from: mtdoc on November 01, 2012, 12:36:30 PM
Vmp of 15? That is a strange Vmp. Are you sure?. 12 Volt panels usually have a Vmp of around 17. 15 would be too low for reliably charging a 12 volt system.
Also - panels with a Vmp of 30 are not really 24 volt panels (which need a Vmp of 35 or so). Panels with a Vmp of 30 are very commonly used for batteryless grid tie systems and now thanks to MPPT contollers, can be used for battery based systems as well.
mtdoc, you are correct: the specs on those evergreens are wrong. I didn't notice :-[
mtfalk64, Vmp x Imp = rated panel watts. For the evergreens 15 x 11.6 = 174. I think mtdoc is correct in his analysis. The Vmp of the evergreens is about 18 volts.
The most important thing is that if you parallel your 30 volt sharps with your 36 volt evergreens, you may be unable to charge your batteries.
Perhaps the best solution is to use two controllers. The evergreens will work well with a PWM (relatively inexpensive) controller and you can use your classic on the Sharps. There is another advantage of two controllers: When you have two types of panels in parallel,
or some partially shaded panels in parallel with some full sun panels,
or when some panels have different exposure than others,
you may confuse the MPPT controller. It may find multiple maximum power points and not be able to pick one best maximum point.
--vtMaps
Quote from: vtmaps on November 02, 2012, 06:08:04 AM
mtdoc, you are correct: the specs on those evergreens are wrong. I didn't notice :-[
mtfalk64, Vmp x Imp = rated panel watts. For the evergreens 15 x 11.6 = 174. I think mtdoc is correct in his analysis. The Vmp of the evergreens is about 18 volts.
The most important thing is that if you parallel your 30 volt sharps with your 36 volt evergreens, you may be unable to charge your batteries.
vtmaps, thanks for doing the math that I was too lazy too do. :-[ And you are right of course that this means the voltage differences are too large to allow parallel strings to make sense.
I agree that 2 controllers would definitely be the way to go. WIth 10 of those 12 volt panels parallel into a PWM controller though he will have 116 amps coming in! Is there a PWM controller that can handle that? If so I suspect it would be more expensive than a second Classic .
Edit: OOPS! Just remembered 24V system means with 2 panel strings it would be 58 amps not 116. A TS 60 would handle that- but it's not that much less ($300) than a classic lite and will not allow future expansion.
Mike - buy a second Classic - you won't regret it. A Classic lite can be had for $500.
Quote from: mtdoc on November 02, 2012, 12:45:42 PM.
WIth 10 of those 12 volt panels parallel into a PWM controller though he will have 116 amps coming in! Is there a PWM controller that can handle that?
He has a 24 volt system, so 5 strings of evergreens with a Imp of 58 amps. --vtMaps
Quote from: vtmaps on November 02, 2012, 12:58:50 PM
He has a 24 volt system, so 5 strings of evergreens with a Imp of 58 amps. --vtMaps
Yep you're right - my bad. I caught myself (see edit above) but you beat me to it!
mtdoc, Yep as soon as I get an extra $600.00 I will be purchasing a second Classic 150. but with limited income I get what I can when I can.
Thanks everyone for your input.