Volts in parallel

[vegas00]

Hi,
Quick question, I know in series the volts are added together and in parallel amps are added. So, if you have a panel with say 10voc and you do a parallel of 3 panels you still have 10voc.

However, if you have shade on 2 panels and as such 1 panel produces 2voc, another produces 1voc then the last is produces 5voc, does that mean the total VOC if tested with a multimeter would be 8voc?
I m trying to work out if the VOC would still be added together in parallel but only up to the 10voc limit.

Did try searching forum and online but everything online just explains difference between series and parallel and not if the volts in parallel add together to the 1 panel limit.

P.s. assuming all 3 panels are the same in above example.

Thanks in advance

 

[Ampster]

Solar panel shading and parallel versus series connections

Hi all, I had an interesting experiment over the last weekend with 2 of my 240W panels. They are side by side and I was measuring their individual outputs as well as their combined parallel and series outputs. I got a result I could not explain (I am sure I am missing something?)...

diysolarforum.com

 

[sunshine_eggo]

Hi,
Quick question, I know in series the volts are added together and in parallel amps are added. So, if you have a panel with say 10voc and you do a parallel of 3 panels you still have 10voc.

However, if you have shade on 2 panels and as such 1 panel produces 2voc, another produces 1voc then the last is produces 5voc, does that mean the total VOC if tested with a multimeter would be 8voc?
I m trying to work out if the VOC would still be added together in parallel but only up to the 10voc limit.

Did try searching forum and online but everything online just explains difference between series and parallel and not if the volts in parallel add together to the 1 panel limit.

P.s. assuming all 3 panels are the same in above example.

Thanks in advance

Your scenario would only happen if you completely obscured a panel with an opaque barrier. Shade primarily impacts current. Even a small amount of indirect light can allow a panel to produce it's full Voc/Vmp, but it need intensity to generate amps.

You would still measure 10Voc in almost every real-world scenario with your 3 proposed panels in parallel.

 

[wattmatters]

However, if you have shade on 2 panels and as such 1 panel produces 2voc, another produces 1voc then the last is produces 5voc, does that mean the total VOC if tested with a multimeter would be 8voc?

Circuit components placed in parallel will have the same voltage. That's what being in parallel does since all components share the same negative and positive terminal connections.

And for solar PV panels, in all practical applications their voltage is either on or off, with on being somewhere in their operational voltage range, and off being nothing. They just won't be in-between, at least not for anything but brief moments.

Here's a chart of the voltage and current from my 2S3P array covering the period from end of one day to beginning of the next. Note the sharp transition in voltage from being in their operational 50-75V range to zero, and then back again:



The spikes in voltage at dusk and dawn are the PWM charge controller trying to squeeze out what it can in low light conditions. Once there is enough light to sustain a useable current, the voltage settles and it then goes into regular daytime mode of adjusting output to match load.

 

[time2roll]

Hi,
Quick question, I know in series the volts are added together and in parallel amps are added. So, if you have a panel with say 10voc and you do a parallel of 3 panels you still have 10voc.

However, if you have shade on 2 panels and as such 1 panel produces 2voc, another produces 1voc then the last is produces 5voc, does that mean the total VOC if tested with a multimeter would be 8voc?

No. The voltage will be 5 Voc. Voc will never go higher than the highest panel when in parallel.

 

[vegas00]

L
Hi all,
Thanks for your feedback and help, very informative.

On a side note, I'm struggling to find a watt /volt / amps meter that loggs the data either to usb or via an app/WiFi. I'm currently using a standard meter from eBay see below)


Which is great and just sits between my panels and my EB150 but it doesn't log anything so I can't see how many watts etc was generated etc per hour.

what are you guys using to monitor your panels power generation?

 

[Pierre]

An MPPT with a display or with Bluetooth / App will tell you.

 

[vegas00]

I'm not sure I can use an MPPT as there is already one in the EB150 power bank that the pannels are plugged into.

Do you know of any watt meter that can monitor the solar watt generation that can sit just behind the panels but before any MPPT or power management system?

 

[Bud Martin]

OP: what does that reading of '8.8Wp' mean?

 

[vegas00]

@Bud Martin
The bottom left rotates between various readings e.g. max volts recorded, max amps recorded, total amps transferred and from memory Wp is total amount of watts transferred. It was at 8.8 since it's late and I'd just changed my panels to parallel instead of series so it had reset and its low since it was close to being nearly dark.

Top left is current amps
Top right is current volts
Bottom right is current watts
These 3 are the figures I'd like to track/record as they fluctuate depending on the MPPT in the bluetti eb150. Something like @wattmatters has above would be fantastic