diy solar

diy solar

Recommend best connection for 3 215W panels

cjssr

New Member
Joined
Dec 23, 2021
Messages
5
I currently have 1-100W panel connected to a Go Power PWM controller that was factory installed on my TC. I just installed 2 UT 1300 Lion Energy batteries along with upgrading the Go Power PWM to latest model with Lithium battery support. I also added a Xantrex XC 2000 Pro inverter to the mix. Now I want to change out the 100W panel and install 3 215W High-Tec panels . Wish I could mount 4 panels just no room to do so. Should I connect 1 to the existing controller and add a Victron 100/50 mppt controller to handle the other 2 connected in parallel? Or can I connect all 3 panels in parallel and do I need a connector box to do so? We are in the PNW so lots of cloudy days unless we are traveling south. Any suggestions greatly appreciated!
 
What is a TC?

Putting all three in series will give you slightly better results overall on days with poor sun if using an MPPT controller. This assumes none of the panels will get shaded from trees or other obstacles.

If you do have shading issues then putting the panels in parallel will likely be better. 3 in parallel normally requires a combiner box and each panel should be fused.

If you post the full specs of the panels then people can help you choose the right charge controller.

Can you verify your system voltage? 12V? 24V?
 
What is a TC?

Putting all three in series will give you slightly better results overall on days with poor sun if using an MPPT controller. This assumes none of the panels will get shaded from trees or other obstacles.

If you do have shading issues then putting the panels in parallel will likely be better. 3 in parallel normally requires a combiner box and each panel should be fused.

If you post the full specs of the panels then people can help you choose the right charge controller.

Can you verify your system voltage? 12V? 24V?
Here are the specs on the panels I am thinking of purchasing. Also the system is 12V The TC stands for Truck Camper which is the limited roof area issue. I had thought of using the existing Go Power PWM for 1 Panel and putting the other 2 in Parallel with a Victron 100/50 which would allow me to do a 2S1P and not use the PWM controller if I am understanding the series/parallel wire setup correctly.
 

Attachments

  • 84A0DC60-4FA2-4327-89AC-EB525BCCE59E_1_201_a.jpeg
    84A0DC60-4FA2-4327-89AC-EB525BCCE59E_1_201_a.jpeg
    209.2 KB · Views: 4
You wouldn’t have anything like 2S1P. That would be two panels in series.

You can easily put all three of those panels in series with a Victron 100/50. No need to use two controllers.

If you really wanted to use one panel with the PWM and put the other two in parallel with an MPPT controller you can use a smaller one such as the 100/30.
 
Here are the specs on the panels I am thinking of purchasing. Also the system is 12V The TC stands for Truck Camper which is the limited roof area issue. I had thought of using the existing Go Power PWM for 1 Panel and putting the other 2 in Parallel with a Victron 100/50 which would allow me to do a 2S1P and not use the PWM controller if I am understanding the series/parallel wire setup correctly.
You wouldn’t have anything like 2S1P. That would be two panels in series.

You can easily put all three of those panels in series with a Victron 100/50. No need to use two controllers.

If you really wanted to use one panel with the PWM and put the other two in parallel with an MPPT controller you can use a smaller one such as the 100/30.
I guess I was thinking that 2S1P meant connecting 2 in series and 1 in parallel with the 2 in series. Novice to this terminology! What would you call 2 in series and then connecting those to the 1 in parallel if that is even possible connected to the Victron controller? Also would I have to up the wire guage to 8 or 6 from the current 10ga to run all 3 in parallel together on the same Victron controller due to increased amperage? And would the standard panel connectors handle those amps?
 
You really should consider putting the 3 panels in series instead of parallel unless you have things on the camper roof that will cast shadows on the panels.

With the 3 panels in parallel on one controller you would need a combiner box and each panel needs a fuse. The resulting output from the combiner box to the charge controller would need to handle about 33A. 8AWG wire would be good for that run.

If you put the 3 panels in series on one controller then the existing 10AWG is plenty and you would not need a combiner box or fuses. This is by far the simplest solution and it actually gives the best results as well if there are no shading issues.

If you put 1 panel on PWM and 2 panels (either parallel or series) on the MPPT then you just have two charge controllers wired into your electrical system. The three panels are not together in any way so there's no terminology for the three panels in that case. You just have one panel on one controller and 2 panels in either 2S or 2P (depending on what you choose) on the second controller.
 
You really should consider putting the 3 panels in series instead of parallel unless you have things on the camper roof that will cast shadows on the panels.

With the 3 panels in parallel on one controller you would need a combiner box and each panel needs a fuse. The resulting output from the combiner box to the charge controller would need to handle about 33A. 8AWG wire would be good for that run.

If you put the 3 panels in series on one controller then the existing 10AWG is plenty and you would not need a combiner box or fuses. This is by far the simplest solution and it actually gives the best results as well if there are no shading issues.

If you put 1 panel on PWM and 2 panels (either parallel or series) on the MPPT then you just have two charge controllers wired into your electrical system. The three panels are not together in any way so there's no terminology for the three panels in that case. You just have one panel on one controller and 2 panels in either 2S or 2P (depending on what you choose) on the second controller.
I have a pretty tall A/C unit to the right of the 2 panels I can mount on the drivers side and 2 maxair vent covers and A/C unit that would cast shadow on the one space I can mount next to the A/C on the passenger side and not understanding the shadowing effect on output if connected in series I was leaning towards connecting all in parallel. Also wanting to put tilt mounts on all 3 to try and offset the northern latitude area we live in as much as possible. The pics are of the roof area with original factory installed 100W panel and rest of congestion on the roof and cardboard template for possible panel placement!
 

Attachments

  • C139A0CA-CEC4-495A-9C4B-2CD97177DB5C.jpeg
    C139A0CA-CEC4-495A-9C4B-2CD97177DB5C.jpeg
    92.1 KB · Views: 1
  • 942ADC51-5B13-4040-8497-2F5A4D700A4B.jpeg
    942ADC51-5B13-4040-8497-2F5A4D700A4B.jpeg
    105.7 KB · Views: 1
  • CD9E06D4-BC74-4B80-8C45-DB21598F868C.jpeg
    CD9E06D4-BC74-4B80-8C45-DB21598F868C.jpeg
    80.8 KB · Views: 1
  • DEACCF6C-8ABF-4D68-BE9A-D8DD16B74208.jpeg
    DEACCF6C-8ABF-4D68-BE9A-D8DD16B74208.jpeg
    121 KB · Views: 1
Given that roof you definitely want the 3 panels in parallel. Too many shading issues for 3 in series.

You can put 1 panel on the PWM controller and 2 panels on a 100/30 MPPT controller. Or you can put all 3 panels in parallel on a 100/50 MPPT controller.

If you use two charge controllers you need to run a second wire from the roof down to where you install the 2nd controller. If you use one new charge controller then you will need to replace the existing 10AWG wire with 8AWG. So either way you have some wiring to do.

If you use two charge controllers then the the two panels on the new MPPT will not require a combiner box or extra fuses. Just get a pair of MC4 Y connectors to connect the two panels together. If you put all three panels on a new MPPT then you need a combiner box and fuses.

I have no experience with PWM controllers so in the end I'm not sure which of the two combinations will end up giving you the best results overall.
 
Given that roof you definitely want the 3 panels in parallel. Too many shading issues for 3 in series.

You can put 1 panel on the PWM controller and 2 panels on a 100/30 MPPT controller. Or you can put all 3 panels in parallel on a 100/50 MPPT controller.

If you use two charge controllers you need to run a second wire from the roof down to where you install the 2nd controller. If you use one new charge controller then you will need to replace the existing 10AWG wire with 8AWG. So either way you have some wiring to do.

If you use two charge controllers then the the two panels on the new MPPT will not require a combiner box or extra fuses. Just get a pair of MC4 Y connectors to connect the two panels together. If you put all three panels on a new MPPT then you need a combiner box and fuses.

I have no experience with PWM controllers so in the end I'm not sure which of the two combinations will end up giving you the best results overall.
Thanks for all your guidance! Since the PWM controller is almost new I think I will give it a shot with 1 panel and the go with the 100/50 controller for the other 2 panels and with the 100/50 I can switch all 3 to mppt controller in the future if not happy with the PWM controller results!
 
Back
Top