Solar Panels - Series vs Parallel I don't know which way to set mine up...

[K7WMC]

I'm very new to DIY Solar for my van. I'm setting up my system with a MPP PIP 800W 12 volt Inverter Charger. But I do not understand if I should connect my panels in Series or Parallel. Mainly because I don't understand the major differences between the two setups. I do understand that with Series the panels are connect Positive to Negative at each panel and if one panel is shaded it will effect all the panels. Where as Parallel connection will only effect the panel that is shaded.
I have 4 new 100W Renogy panels for my new system currently but might add another panel for a total of 500W later after my initial setup. So my question is for @Will Prowse what do you recommend for the MPP PIP 800W Inverter? Series or Parallel with 400 watts of panels? I do recall you mentioned in your video of the 800W unit (no more than 500 Watts) and I will not be exceeding that amount. Is there advantages of one method over the other? Which is more efficient with a system my size? Is a Parallel setup more complex? I understand that I have to have MC4 branch connectors for a parallel setup. I understand that some people do both Series and Parallel. Sorry I'm so naive on this subject but it is difficult for me to understand. Any recommendation or advice on this will be followed to the letter. I will be using 2 Battleborn 100ah for my battery bank. Thanks in Advance.

 

[offgriddle]

I recently rewired a pair of 12 volt panels hooked in parallel, (thus producing 12 volts), and connected them in series to produce 24 volts. I did this because there is less loss in the wires at higher voltage. Of course, one must make sure that the charge controller can accept the higher voltage input from the panel. ~~~ To hook up two panels in parallel, combine the positive from one panel with the positive of the other panel, and the negative of one panel with the negative of the other panel, and the output voltage will remain at 12. ~~~ To hook up two panels in series, connect the positive of one panel to the negative of the other panel. You will then have 24 volts present on the other positive of one panel and the others negative of the other panel. ~~ Series parallel connection is required when you have more than two panels and you have to maintain a certain voltage like 24, 36, etc.

 

[Deleted member 783]

Connecting 4 panels in series will give you 48 volts and about 6 amps. Parallel will give you 12 volts and 24 amps. Higher voltage is more efficient, and lower amps mean you can use less expensive wire (smaller gauge).

 

[K7WMC]

Connecting 4 panels in series will give you 48 volts and about 6 amps. Parallel will give you 12 volts and 24 amps. Higher voltage is more efficient, and lower amps mean you can use less expensive wire (smaller gauge).

New Mexico Will, so you're saying "series" is more "efficient" and is the bigger bang for the buck? And even though the panels are producing "more voltage" the charge controller determines how much voltage to charge your battery bank at? Am I thinking correctly about that?

 

[Deleted member 783]

New Mexico Will, so you're saying "series" is more "efficient" and is the bigger bang for the buck? And even though the panels are producing "more voltage" the charge controller determines how much voltage to charge your battery bank at? Am I thinking correctly about that?

Yes sir, just make sure your SCC (solar charge controller) can handle the voltage and amperage that your panels are sending to it. You need to match the battery voltage to your panel voltage, as well as the inverter. So if you wire the panels in series (48volts) you'll want a 48 volt battery bank and a 48 volt inverter. The inverter will accept your DC 48 volts and output AC120v. (usa setup)

 

[Rider]

New Mexico Will, so you're saying "series" is more "efficient" and is the bigger bang for the buck? And even though the panels are producing "more voltage" the charge controller determines how much voltage to charge your battery bank at? Am I thinking correctly about that?

More correctly, the solar charger will (generally, depending on model) know what voltage batteries are connected, 12/24/48. The charge controller will charge within the correct voltage range while varying the charge amps.
As a rule, it's better to have higher voltage rather than higher amp feeding the charge controller.

 

[Deleted member 783]

More correctly, the solar charger will (generally, depending on model) know what voltage batteries are connected, 12/24/48. The charge controller will charge within the correct voltage range while varying the charge amps.

But it is necessary to match all system voltages, right?

 

[Rider]

But it is necessary to match all system voltages, right?

Only in the respect that if your batteries are 24V, you need a 24V inverter and charge controller capable of connecting to a 24V battery. The input voltage from the panels does not have to match, ie the panel voltage could be 96V, feeding a 24V battery.

 

[Deleted member 783]

Only in the respect that if your batteries are 24V, you need a 24V inverter and charge controller capable of connecting to a 24V battery. The input voltage from the panels does not have to match, ie the panel voltage could be 96V, feeding a 24V battery.

My apologies for putting bad info out there. I thought everything needed to match voltages. So, a person could wire 4 renogy 100 watt panels in series (48 volts), and the charge controller can charge a parallel 12 volt battery bank? (not saying this is a good idea, just wondering)

 

[Rider]

My apologies for putting bad info out there. I thought everything needed to match voltages. So, a person could wire 4 renogy 100 watt panels in series (48 volts), and the charge controller can charge a parallel 12 volt battery bank? (not saying this is a good idea, just wondering)

Yes, and is done all the time. In this case an MPPT charge contoller would be recommended.

This has all been documented in the Learning section of this forum. Check it out.

 

[svetz]

This has all been documented in the Learning section of this form. Check it out.

You might also try the Beginner's Corner, these might help you out:

• Beginner Video Playlist
• What does it mean to have solar panels in parallel and series?
• How to figure out how much Solar and inverter wattage is needed to charge a battery
• Figuring out how many panels in series and parallel based on your MPPT
• What wire gauge should I use? (video, calculator)
• Comparing Solar Panels
• What should you pay for a Solar Installation?
• How can I find out which solar panels are damaged?
• This isn't working, how do I troubleshoot it?
• I made this! Is it safe?
• Grounding PV
• Battery FAQ
• Basics of Wind Loading
• Some useful calculators

 

[Deleted member 783]

Well, I'm off to rewire stuff

 

[Rider]

Well, I'm off to rewire stuff

Before you do that, check the manual for your charge controller to make sure what you plan on doing will be ok, ie not exceed input volts OR watts.

 

[Deleted member 783]

Before you do that, check the manual for your charge controller to make sure what you plan on doing will be ok, ie not exceed input volts OR watts.

I hope I haven't derailed this thread, but I have the same panels as the OP so I think it's all relevant. My renogy wanderer will take 40 amps, 12/24 volt input. So, with 4 panels, am I correct in assuming that the best way to go would be to wire 2 panels in series, wire the other 2 in series, and wire the strings together in parallel? I believe that will give me 24 volts and about 12 amps.

 

[Rider]

I hope I haven't derailed this thread, but I have the same panels as the OP so I think it's all relevant. My renogy wanderer will take 40 amps, 12/24 volt input. So, with 4 panels, am I correct in assuming that the best way to go would be to wire 2 panels in series, wire the other 2 in series, and wire the strings together in parallel? I believe that will give me 24 volts and about 12 amps.

Again, check your manual. I see a 30A Wanderer, so I took specs from that.

The Renogy Wanderer Li 30A Negative PWM Charge Controller
Nominal Voltage: 12 VDC	Max. PV Input Power: 400W
Rated Charge Current: 30A	Max. PV Input Voltage: 25 VDC

You cannot exceed 25VDC from your panels, and that is VoC voltage, not rated voltage. VoC voltage can be significantly higher, check your panel specs. If the panels are 100W, you may have to be limited to all 4 in parallel. Honestly, if you have 4 panels, replacing the PWM controller with an MPPT controller might be suggested. Wider input range, greater flexibility in configurations, more efficient power transfer.

 

[Deleted member 783]

I"m good at 100 volts. I hope this helped K7WMC.

Robot Check

 

[Rider]

I"m good at 100 volts. I hope this helped K7WMC.

Robot Check

Ok, you said Wanderer, so that's what I referenced. You are OK with the Rover. Big difference.....

 

[Deleted member 783]

Ok, you said Wanderer, so that's what I referenced. You are OK with the Rover. Big difference.....

Sorry. 7am on a Saturday...

 

[Donald Siegel]

On thing I found when deciding on series and or parallel using my 24v MPPSolar PIP is the manual shows 145v PV Max, 80 amps max. Yet at 125 v in my full series connection of four 250w panels it shuts down. If I parallel 4 panels (roughly 8 amps each) it won’t detect the panels (amps too high) but does fine with three. I ended up 2 in series 2 in parallel. In short read the manual yes, but for PIP divide by 2! I love the PIP, just don’t believe the specs.

 

[Deleted member 783]

My renogy 100watt 12 volt mono panels are 22.5VOC! Almost double! Interesting that it doesn't say 12 volts anywhere on it, but that is how it's sold.