Which is correct/better ?

[Aceallenk]

My DIY item I've purchased consists fora 12V trailer system with about 220AH, Renogy Rover 40A MPPT controller, and 4 Renogy 100W 12V panels. with 8AWG copper wire. Should I hook the 4 panels in series or parallel ? Have had some say I can hook ONLY IN PARALLEL, and another say ALL IN SERIES, and another say 2 sets of series then in parallel. Does the controller bring this all down to 12 volt or if I hook everything in series will create an instant bonfire or have batteries boiling and blowing up? I'll share a link to the image of a 400W system wired in series, that would almost match my ideal, if it's wise !!! https://cdn11.bigcommerce.com/s-4zq...6153247281412801280__72725.1561107064.jpg?c=2

 

[Craig]

Either way is fine Not sure of your panel specs but I like series better if there are no shading issues because it allows for less loss in the lines between the PV and SCC. The SCC will take up to its maximum input (100 volts in this case) volts and take it down to 12 volts.

 

[Aceallenk]

So lets say there is a tree that could cast a shadow on half a panel, in series will this effect all panels and nothing works? Because there are a few spots we park that trees are near? This is the area I'm a little buffaloed as to a best set up..

 

[Craig]

With modern panels this will not shut the whole system down just one panel they should have bypass diodes in them to solve issues with shading. But if one whole panel is shaded you will obviously lose the energy production from that panel.

 

[grizzzman]

Parallel if boondocking . There is little advantage with 12 volt panels going with MPPT due to panel heating issues.( Unless you camp in the cold) In parallel if you are shaded on one panel, you only loose that panel. Modern high voltage panels can work around shading, but not 12 volt panels.

 

[Aceallenk]

They do have those DIODES you speak of Craig.. So Grizzman would it not then be better to be hooked in series as Craig suggests? Would it not be the same in series or parallel, that if a panel is shadowed, that panel is not working, sounds the same either way. And doesn't the current travel better hooked in series to the controller than in parallel. Here is the spec to the panels I am using. 2 minutes ago I was convinced series was the way to hook my panels, now maybe there isn't a better way over the other. But I do think series has a better flow of current through my 8awg copper wire which will be a 25-30 foot run to the controller. hence my reason for 8Awg instead of the 10 suggested.
Specifications

• Maximum Power: 100W
• Maximum System Voltage: 600V DC (UL)
• Optimum Operating Voltage (Vmp): 17.9V
• Open-Circuit Voltage (Voc): 21.6V
• Optimum Operating Current (Imp): 5.72A
• Short-Circuit Current (Isc): 6.24A
• Dimensions: 42.2 X 19.6 X 1.38 In
• Weight: 16.5lbs

 

[grizzzman]

I suggest that you test the Shading affects on 12 volt panels. Shade the lowest cells across as I have with the panel aimed at the sun.watch voltage, using this method you will see for yourself what the truth is.

 

[Aceallenk]

Grizzzman, so what are you saying? First off I don't have anything set up or installed yet, but rather trying to understand which method is better, And your correct this is for a trailer, boondocking. with an inverter and a inverter/generator for backup and to run the air conditioner on super warm afternoons. I really perfer to cut my MC4 wire once and live with it, either it be parallel or series, and guaranteed tree shadows will be a factor, so which method is better to deal with that factor, using the system I have already purchased? I also thank you for your time to reply to this post.

 

[grizzzman]

All my camping is boondocking. For me it's simple, depending on how the shadow is cast on the panel can completely block a 12 volt series panel set up. But if in parallel, you only loose the one panel. You may want to run 6 AWG so when you wanna upgrade (and it's likely) solar is a sickness.?

 

[Aceallenk]

The reason I went with 8Awg is because they recommended 10Awg. But yea this is the same boon-docking camping, sometimes trees could play a factor so definitely trying to find and understand the best plan of attack when I start to install my panels on the roof, and really only want to cut up copper wire once. Another quick question, do you support the ideal of a 10A MC4 fuse at each positive at every panel?

 

[grizzzman]

Just another failure point. So no I don't. Just on the battery side.

 

[Aceallenk]

Thanks, I also just ordered some 6Awg to, lol. Time to get everything I want, the way that makes the best scene ordered up now. The 8Awg that I ordered a couple weeks ago arrived and I wasn't overly impressed with it anyways, was stiff and low in strand count and was kinda planning too find something a little better. So parallel it is, with heavier 6awg pure copper, lol. You know what they say, if your going to do a job, ''you might as well do it as well as you can'' and if your at all fussy, there's always room for improvement. Thanks Grizzz, really appreciate you help also and Merry Christmas to you.

 

[grizzzman]

Good luck with your project ! And Merry Christmas back at ya!

 

[grizzzman]

His controller is rated for 520 watts 40 amps. His panels are 100 watts X four. 400 watts and best case 25 amps (likely a pipe dream ) at best. He is well within the controller spec.