7 or 8 - 100 watt 18 volt panels into 150 Classic - SERIES or PARALLEL, or both?

Started by 73-GMC-RV, November 16, 2017, 12:16:57 AM

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73-GMC-RV

I am new to solar, I live in my Rv full time

I currently have

7 - 100 watt panels I am installing this week on my RV.  I may be able to squeeze in 1 more making it 8 total.  These are 18 volt panels.   If I wire them into series I should get 126 volts. Correct?

I am using MidNite Solar Classic 150 MPPT Charge Controller,  150 volts (96 amps)


my system so far:
mounting flat on my RV roof , living in southern CA for now.

7 - ALLPOWERS Flexible Solar Panels 100W 18V
Midnite Solar Classic 150 Charge Controller 150VDC Input MPPT
Magnum MS2812 2800W Inverter with 125 Amp Charger
12 VOLT - 4 Lifeline 6 volt SERIES and PARALLEL = 600Ah total - I may add another bank this year for total of 1200ah

***** should I wire in Series or PARALLEL, or both? **********

THANKS



ClassicCrazy

Midnite has a PV calculator - plug your numbers in there and see what you get . We can give you more info or suggestions after you try that out.
http://www.midnitesolar.com/sizingTool/displaySizing.php

Best practice is to keep the PV voltage closer to  your battery voltage if possible because then the controller will generate less heat and be more efficient. So if you have 8 panels you could go 4 series two parallel . Or with 12 v  2 parallel  4 series should work too. Try out the calculator above with various options.

You are running 12v ?

It gets tough to get all the batteries balanced when you get too many parallel because all the wires need to be the exact same same lengths otherwise you can get different currents to each one .  Looks like you already have your 12v inverter or else the suggestion would probably have been to go to 24v and use a DC to DC converter to get the 12v for any 12v loads.

Larry
system 1
Classic 150 , 5s3p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system 2
 5s 135w Kyocero , 3s3p 270w Kyocera  to Classic 150 ,   8s Kyocera 225w to Hawkes Bay Jakiper 48v 15kwh LiFePO4 , Outback VFX 3648 inverter
system 3
KID / Brat portable

ClassicCrazy

I wonder how they come up on the PV with that 100w maximum watts statement at top ?  The rest of the specs say
2.7 amps x 18v = 48.6 watts

Larry
system 1
Classic 150 , 5s3p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system 2
 5s 135w Kyocero , 3s3p 270w Kyocera  to Classic 150 ,   8s Kyocera 225w to Hawkes Bay Jakiper 48v 15kwh LiFePO4 , Outback VFX 3648 inverter
system 3
KID / Brat portable

ClassicCrazy

Looks like you put the numbers in right but I still don't get why your panels say 100 watts - seems like they are stretching the truth there. Maybe someone can correct me if I am wrong . 
From what the specs say those are more like 50 watt panels and not 100 watt panels.
Two of them in series or parallel would be 100 watts but not just one panel.
Not sure where you got them from but maybe you can ask your supplier for explanation - or refund if you were deceived for what you think you were getting.

Larry
system 1
Classic 150 , 5s3p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system 2
 5s 135w Kyocero , 3s3p 270w Kyocera  to Classic 150 ,   8s Kyocera 225w to Hawkes Bay Jakiper 48v 15kwh LiFePO4 , Outback VFX 3648 inverter
system 3
KID / Brat portable

73-GMC-RV

Sorry. I was reading the specs from Amazon,  I found different numbers on the panels .


I will go back and put in the correct numbers.  It appears that I will only need 6 panels instead of 7 planned, or will I be OK with loss of voltage, etc from wire, connections, etc?

ClassicCrazy

You would probably be better off with 2 in series strings and 3 of those strings in parallel for reasons mentioned earlier - closer string voltage to battery voltage is better .
Try that in calculator
Larry
system 1
Classic 150 , 5s3p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system 2
 5s 135w Kyocero , 3s3p 270w Kyocera  to Classic 150 ,   8s Kyocera 225w to Hawkes Bay Jakiper 48v 15kwh LiFePO4 , Outback VFX 3648 inverter
system 3
KID / Brat portable

73-GMC-RV

Using these numbers>
PV Array

Number Of Modules In Series   
2

Number Of Parallel Strings   
4

Total Modules   8


I think this is my best option, I will try and get some zzz and try and figure how to best wire this up.

Thanks for the help, I am new, controller is in the mail still from Midnite.com so I am glad my first day here was fruitful with some great help.

ClassicCrazy

Your next step would be to calculate the voltage drop for the distance of the wire you would use to go from PV to Breaker Box. You can always go to the 3 s 2 p if you needed increase PV input voltage to be able to go to smaller wire gauge to breaker box.

Not sure what you are using but if you haven't picked anything out yet I recommend Midnite Mini DC box - it has all the holes and breakers to easily install Classic, shunt, whizbang, and has the big breaker for your inverter and breakers for PV input , battery charge , and extras for DC loads. This box makes wiring a lot easier and neat.

Larry
system 1
Classic 150 , 5s3p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system 2
 5s 135w Kyocero , 3s3p 270w Kyocera  to Classic 150 ,   8s Kyocera 225w to Hawkes Bay Jakiper 48v 15kwh LiFePO4 , Outback VFX 3648 inverter
system 3
KID / Brat portable

73-GMC-RV

I decided to wire (3 panels in series) and 2 strings of them in Parallel. 6 total panels

If I added 3 more panels in series later, 3 strings, would that still be within reason. I am not concerned with voltage drop and this RV is super small. 26 ft end to end and only 8 ft tall.


ClassicCrazy

Let us know how it is all working when you get it done.

Also this is good info on wiring batteries to keep them in good balance .

http://www.smartgauge.co.uk/batt_con.html

Larry
system 1
Classic 150 , 5s3p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system 2
 5s 135w Kyocero , 3s3p 270w Kyocera  to Classic 150 ,   8s Kyocera 225w to Hawkes Bay Jakiper 48v 15kwh LiFePO4 , Outback VFX 3648 inverter
system 3
KID / Brat portable

73-GMC-RV

I used 8 AWG wire down to my controller from the panels.  I do not have them connected together yet in the picture, incase anyone caught that.

I have 600 watts total  in 6 panels as described above.   What size breaker (fuse)  do I need to use for the solar side before connecting to the Controller for the wire coming from the solar panels to controller?



ClassicCrazy

You fuse what the wire is rated for . You could use a smaller breaker but can't go larger.
Here is a chart for breaker sizes which depends a bit on which kind of wire you used.
http://www.cerrowire.com/ampacity-charts

Larry
system 1
Classic 150 , 5s3p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system 2
 5s 135w Kyocero , 3s3p 270w Kyocera  to Classic 150 ,   8s Kyocera 225w to Hawkes Bay Jakiper 48v 15kwh LiFePO4 , Outback VFX 3648 inverter
system 3
KID / Brat portable

73-GMC-RV

Thanks for the wire chart today, that explains allot.

This is a good learning experience.

I just hope all is done correctly over here before I turn her on.

Thanks again for the reply.

Bruce

ClassicCrazy

You have been doing your homework so you should be okay .

You could also draw the whole system out as a schematic to double check it too.
Larry
system 1
Classic 150 , 5s3p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system 2
 5s 135w Kyocero , 3s3p 270w Kyocera  to Classic 150 ,   8s Kyocera 225w to Hawkes Bay Jakiper 48v 15kwh LiFePO4 , Outback VFX 3648 inverter
system 3
KID / Brat portable

Resthome

Quote from: 73-GMC-RV on November 26, 2017, 11:56:49 AM
I have combined the 2 string on the roof already, but after getting the 8 awg wire down into RV closet. 

Would this be an option to just add breaker to the line and possibility of adding external movable panels later with one of these?

http://www.midnitesolar.com/products.php?menuItem=products&productCat_ID=10&productCatName=..

I only have the on circuit now but may add 1-2 later.

Thanks
I can email support but I appreciate the forum as its from real users.

BRuce

Each string should have a breaker and then one at the Classic to act as a disconnect to remove all PV.
I'd use the Quad box as it takes panel mount breakers that are not polarity sensitive. The othe boxes are for din rail breakers and they are polarity sensitive.
John

10 x Kyocera KC140, Classic 150 w/WBJr, Link10 Battery Monitor, 850 AH @ 12v Solar One 2v cells, Xantrex PROwatt SW2000
Off Grid on Houseboat Lake Don Pedro, CA