Solar Panels

alwaysared

alwaysared

Full Member

Messages
819
I've ordered two 150w solar panels from Midsummer along with a Victron 100/30 BlueSmart Controller from Onboard Energy and I've received an email from Midsummer telling me that the panels I've ordered are unable to be wired in series and must be wired in parallel, is this a disadvantage or will I still get good charge rate (when the suns out) ?

Regards,
Del
 
alwaysared said:
I've ordered two 150w solar panels from Midsummer along with a Victron 100/30 BlueSmart Controller from Onboard Energy and I've received an email from Midsummer telling me that the panels I've ordered are unable to be wired in series and must be wired in parallel, is this a disadvantage or will I still get good charge rate (when the suns out) ?

Regards,
Del
Click to expand...
Interesting. Usually the limitation about running in series would be due to the controller you are using with the panels. If the Voc of the panels is below 50V each (which I would think would be the case!) then the 100/30 Victron should have no problems either way.
I don't think it would make any noticable difference in real terms but personally I would like to have the choice and would ask Midsummer for the explaination why.
 
wildebus said:
Interesting. Usually the limitation about running in series would be due to the controller you are using with the panels. If the Voc of the panels is below 50V each (which I would think would be the case!) then the 100/30 Victron should have no problems either way.
I don't think it would make any noticable difference in real terms but personally I would like to have the choice and would ask Midsummer for the explaination why.
Click to expand...
This is from Midsummer:
I just wanted to check something with you, are you planning to put the 150w flexi panels in series?

If so, unfortunately we have to advise you not to, they must go in parallel due to their max voltage being 45v.

If you're ok to do this, we can provide a branch connector or additional pair of solar cables for you.

So the reason is the voltage, I've checked out a couple of videos and there seems to be no noticable difference either way using a decent MPPT controller, in my head I assumed that more volts would equal more amps but I hadn't figured in the MPPT controller would still output a similar amps to the battery.

Regards,
Del
 
Tell them you're using the victron and ask does that make it ok in series?

And stop double posting on both forums lol.
 
The panels specs:
  • Rated power: 150W
  • Voltage Voc: 30.1V
  • Current Isc: 6.35A
  • Dimensions: 540 x 1460 x 3 mm
  • Weight: 3.15 kg
I could in teory use the same panel but have the 110W version:
  • Rated power: 110W
  • Voltage Voc: 21.9V
  • Current Isc: 6.32A
  • Dimensions: 540 x 1070 x 3 mm
  • Weight: 2.18 kg
I just want to harvest as much power as possible and roof space is at a premium so the 150W is largest (in physical terms) that I can fit and I'm racing against time before I go to Hereford next week.

Regards,
Del
 
St3v3 said:
Tell them you're using the victron and ask does that make it ok in series?
Click to expand...
They said the Victron doesn't make it possible either, I'm not bothered which way really, it's just that I had series in my head as being better but it doesn't appear that there's much if any difference once it comes out of the controller.

St3v3 said:
And stop double posting on both forums lol.
Click to expand...
Why? I want to reach the widest audience possible. ;) Please don't make me choose :(

Regards,
Del
 
2 x 150W Panels, each 30V, 6.35A.
In Parallel, they would present 30V and 2 x 6.35A (12.7A) into the Controller
In Series, they would present 2 x 30V (60V) and 6.35A into the Controller
In both situations, the MPPT Controller would convert the excess voltage into higher current so the amperage and voltage coming OUT of the controller will be the same for both options.
Both add up to the same Power coming in with the only differences being the higher voltage when in series will mean slightly less cable losses, but if in parallel, effects of shading on one panel will not affect both panels - so pros and cons to both, but in reality unlikely to notice difference either way (but as I said, it is nice to have the option!)

The explanation from Missummer makes no sense to me TBH and if they are selling you the 100/30 controller along with the panels, their advice is a little worrying with respect to their knowledge on the specifications of the component pairing :rolleyes:
 
Phil said:
Flexible solar panels are not normally made for installation in arrays, this is why the array voltage is most likely so low.

Can I ask why to are fitting flexible panels? In my experience, most of them fail within 2-3 years.
Click to expand...
To save on weight mostly, I'm soon to be embarking on full time vanlife so payload is the most important thing for me.

Regards,
Del
 
Current per panel doesn't change but if joined in parallel the cable to controller carries double with consequent power loss.
 
Trek said:
panels are limited in the current that they can handle ?
Click to expand...
panels don't 'handle' current - they output it ;) The limiting factor with current will be the cabling and the controller.
For the panels in the kit that alwaysared is getting, the controller is not limited and the cabling he will is using is very unlikely to be an issue at a 13A Maximum.
 
I have my flexible solar panels connected in a mix of series and parallel. 4 off 100watt lensun panels with a Victron a 100/30 smart controller.
I noticed a big difference by upping the circuit voltage.
It's the lower light levels that help performance, your charging earlier in the morning and later at night.
Also on dull overcast days the charge current is better.
I did have 5 panels installed, but have removed one with no noticeable loss.

Mark
 
More thinking on this whilst I'm supposed to be working.
How does a panel know what voltage is passing through it?
If it's OCV is 30 volts and is connected in series with another panel of the same type it each will still be OCV 30 volts
So you would have 0v to 30v on one panel and 30v to 60v on the other panel relative to 0volts (ground)
The current will not change. Look up Kirchoff's laws for a better explanation.
The only real danger if you connect enough panels together in series is that you might exceed the insulation strength somewhere to ground.
 
Mark makes a good point about series connection delivering a higher voltage at lower light levels - I hadn't thought about that before.
 
alwaysared said:
The panels specs:
  • Rated power: 150W
  • Voltage Voc: 30.1V
  • Current Isc: 6.35A
  • Dimensions: 540 x 1460 x 3 mm
  • Weight: 3.15 kg
I could in teory use the same panel but have the 110W version:
  • Rated power: 110W
  • Voltage Voc: 21.9V
  • Current Isc: 6.32A
  • Dimensions: 540 x 1070 x 3 mm
  • Weight: 2.18 kg
I just want to harvest as much power as possible and roof space is at a premium so the 150W is largest (in physical terms) that I can fit and I'm racing against time before I go to Hereford next week.

Regards,
Del
Click to expand...
Thought I would just show a wee bit of info which makes me wonder why Midsummer are saying what they are saying ....

1565993881092.png
Voltage into the controller (A Victron 100/30 as you are getting) is 69.38V so would be above the two panels you are looking at connected in Series.
I've included the output from the Controller so you can see how the voltage and current gets changed. (PS. the current is only recorded to one decimal place so the actual Watts in and out are not 100% accurate but does show the quoted 98% efficiency of the Controller is being acheived)


Markd said:
Mark makes a good point about series connection delivering a higher voltage at lower light levels - I hadn't thought about that before.
Click to expand...
Just on this note, the Victron MPPT Controller that is proposed switches on when the Vpv (Voltage of the Solar Array) is at Vbat (the Leisure Battery voltage) +5V; and will stay on and harvesting all the time the Vpv remains >1V above Vbat. So the solar controller can turn slightly earlier at higher voltages and turn off slightly later, but in reality the amount of power harvested at that marginal extra time is so small it is of very little consequence once you get past a certain Array Voc.

But the general advice from Victron is:
Conclusion:
When using an MPPT charge controller there are two compelling reasons to increase the PV voltage (by increasing the number of cells in series):
a) Harvest as much power as possible from the solar array, even at high cell temperature.
b) Decrease cable cross sectional area and therefore decrease cost

The following article is about MPPT vs PWM but actually contains a lot of good info about solar panels and MPPT Controllers and is an interesting read if you want to know more about what to expect from an array and also how MPPT Controllers work - Which solar charge controller: PWM or MPPT?
 
I wonder what the diodes are rated at in the panel? That might be the limiting factor if they are only 50v, bit stupid to fit them if they are only rated at that.
 
PeteS said:
I wonder what the diodes are rated at in the panel? That might be the limiting factor if they are only 50v, bit stupid to fit them if they are only rated at that.
Click to expand...
As mentioned earlier each panel won't see the total circuit voltage when connected in series.
 
SquirrellCook said:
As mentioned earlier each panel won't see the total circuit voltage when connected in series.
Click to expand...
Indeed so.
Same is if you built a 12V battery bank from a pair of 6V T105 Trojan Batteries. To make 12V, in series one is "0V to 6V" and the other is "6V to 12V", but individually they are still 6V each. It is the voltage differential between the devices Negative and Positive connections that determines the voltage of/into the device.
 
You must log in or register to reply here.

Users who viewed this discussion (Total:0)

Back
Top