Solar panels in series or parallel, pro and con

[SolarPoweredRV]

My controller is limited to 50 amp output so probably 4 - 6 panels depending on the panels and the amount I allow for derating. I haven't considered the panel voltage output and has to be my learning curve. Question on a different topic. How strong are these panels. The reason I ask is this last weekend I was parked under an oak tree which didn't mean much until the wind blew in the middle of the night and I thought someone was banging on the coach with a hammer. How much concern needs to be put into falling debris with selecting the panel source?

All of your Solar panels use Tempered glass which is resistant to hail, however, if you get caught in a hailstorm with baseball sized hail you are probably going to be replacing at least some of your panels. As far as wind goes, most panels are designed to resist strong winds, most are probably rated to resist hurricane force winds, but I don't know for sure. Since I was mounting my panels on the top of my RV, I added an extra pair of "Z" brackets to each panel to ensure they stay on the roof (total of 6 brackets for each panel). At the end of the day Mother Nature is in charge.


To set your mind at ease, you can read the following article about the resilience of Solar Panels...

Link: https://aresolar.com/can-hail-damage-solar-panels/

[powerscol]

There appears to be an issue when partial shading occurs, but even the experts disagree. Series is better on overcast days.
https://www.youtube.com/watch?v=n3_lKIAcYsM
https://www.youtube.com/watch?v=ofo1HQyGG8s
https://www.youtube.com/watch?v=1qD3mN8VotQ

[SolarPoweredRV]

There appears to be an issue when partial shading occurs, but even the experts disagree. Series is better on overcast days.
https://www.youtube.com/watch?v=n3_lKIAcYsM
https://www.youtube.com/watch?v=ofo1HQyGG8s
https://www.youtube.com/watch?v=1qD3mN8VotQ

Bottom line: you simply make the best decision you can. If you don't like the performance, you can simply re-wire your panels to try to improve your performance.

Additionally, if possible, add an extra Solar panel (or two) to oversize your system so you don't need to worry about getting the maximum out of your panels, this also helps your Solar perform better during the Winter months, due to the low angle of the Sun.

[Scramjet]

Parallel vs series and shading is seldom a black and white issue (pun intended). I have a medium sized 12v system with 400w solar and 300ah of flooded LA batteries. I could have gone parallel or series or SP combination but I went series because of the lower light conditions and cloudy skies that I expect to see. Under those conditions a higher voltage series array will turn on the MPPT controller earlier. In a perfect world I would double the solar. That way you get higher voltages and also get the SP advantages.

[DarthMuffin]

In general I think series up to the voltage limit of the MPPT charge controller will be most efficient and use the smallest/lightest wire as well. I install with series up to about 50V and then put the series in parallel if you have more. I use the 50V limit because that's when DC starts to become dangerous and can break the dielectric of skin.

[wjpatter]

There appears to be an issue when partial shading occurs, but even the experts disagree. Series is better on overcast days.
https://www.youtube.com/watch?v=n3_lKIAcYsM
https://www.youtube.com/watch?v=ofo1HQyGG8s
https://www.youtube.com/watch?v=1qD3mN8VotQ

Excellent demonstrations about the effects of shading. Seldom do I ever park in total direct sun so shading is going to seriously effect my panel design. I hate to turn my roof into something that looks like a switch closet but losing a single cell is dramatic.

[Grey65]

I have (4) 330 watt panels and I wired them in series-parallel. They feed a Victron 150/85 controller which feeds into 3 BattleBorn batteries which in turn powers my 3,000 watt Victron inverter. But as previously written all depends on where and how you camp as to what will work best for you.

[Whiteley RV]

We have 1880Watts of Solar (2 separate arrays) on our RV; all in parallel in the event one of the panels ceases to function and it does not affect the balance of the two arrays.

[wjpatter]

Bottom line: you simply make the best decision you can. If you don't like the performance, you can simply re-wire your panels to try to improve your performance.

Additionally, if possible, add an extra Solar panel (or two) to oversize your system so you don't need to worry about getting the maximum out of your panels, this also helps your Solar perform better during the Winter months, due to the low angle of the Sun.

Good point about the low angle of the sun. My target is 50amp to the batteries so oversizing is a really good suggestion. When I started cartooning possible panel layout, I realized that the roof slants, AC shading, and parking orientation would all effect my overall efficiency. If I understand the shade demonstration from the you-tube video's, the panel output is only as good as the weakest cell (shaded cell). That isn't what I expected. Given all that, I would put as many 50w panels in parallels as I could get but, unfortunately, the difference in cost between a 50w panel and a 100w panel is minimal so I'm hard pressed to consider the 50w unless I can get them dirt cheap. It also occurred to me that if I put as many panels as possible, I won't be able to move around the roof so I'm going to be in the planning phase for a while. The usable foot print on the roof was less than I expected, given the shading from the air conditioners. This job is starting to hurt my head.

[wjpatter]

Parallel vs series and shading is seldom a black and white issue (pun intended). I have a medium sized 12v system with 400w solar and 300ah of flooded LA batteries. I could have gone parallel or series or SP combination but I went series because of the lower light conditions and cloudy skies that I expect to see. Under those conditions a higher voltage series array will turn on the MPPT controller earlier. In a perfect world I would double the solar. That way you get higher voltages and also get the SP advantages.

I'm still digesting the you-tube shading videos but it looks like a panel output is limited to the poorest performing cell so if part of a panel in series is shaded, that cell will dictate how much power is produced by the panel. Clearly, I need to do more research. I've studied my owners manual for the Renogy DC-DC converter and it seems to be pretty sophisticated. I has input two ports, one from my starter battery in the truck and a second for solar input. The starter battery port is designed not to drain my truck battery so under it doesn't draw power unless the ignition is on using a control line that I've wired to my running lights (poor man's on/off switch). The solar port seems to operate independently, given charging priority to solar and doesn't seem to have a low voltage cut off. I'll see if I can get clarification from Renogy Tech Support.