Wiring series vs parallel question

[whereitsat42]

I know when wiring solar panels in parallel, the length of the cable runs on the positive and negative sides need to be equal, but does the same limitation apply when wiring the panels in series? Or is any total length of the run okay as long as staying within the bounds of the distance/current the wiring supports?

 

[sunshine_eggo]

I know when wiring solar panels in parallel, the length of the cable runs on the positive and negative sides need to be equal,

Nope. Not at all a thing.

For parallel batteries, total (+) + (-) length needs to be the same to ensure that batteries share current equally.

Who cares if panels don't share current equally. In most cases, you want as much as they'll deliver.

but does the same limitation apply when wiring the panels in series? Or is any total length of the run okay as long as staying within the bounds of the distance/current the wiring supports?

There is no good reason for making PV wires any longer than they need to be in any configuration.

 

[whereitsat42]

Nope. Not at all a thing.

For parallel batteries, total (+) + (-) length needs to be the same to ensure that batteries share current equally.

Who cares if panels don't share current equally. In most cases, you want as much as they'll deliver.



There is no good reason for making PV wires any longer than they need to be in any configuration.

Okay, that makes sense actually, and yeah, I wasn't planning on making them any longer than they needed to be, just one end of the mount holding the panels is about 2 feet away from the junction box I'm going to connect them to, and the other end of the mount (and daisy chain) is about 8-10 feet away, and I wasn't sure if having a 2 foot wire on one end and a 10 foot wire on the other would be an issue/blow up my system. But that would be okay?

 

[sunshine_eggo]

Okay, that makes sense actually, and yeah, I wasn't planning on making them any longer than they needed to be,

Technically you were. Your approach would have made the panel 2 feet away with notably longer cables to meet your criteria.

just one end of the mount holding the panels is about 2 feet away from the junction box I'm going to connect them to, and the other end of the mount (and daisy chain) is about 8-10 feet away, and I wasn't sure if having a 2 foot wire on one end and a 10 foot wire on the other would be an issue/blow up my system. But that would be okay?

LOL... I've definitely given you enough to draw your own conclusion. You could have 2 feet on one end and 500 feet on the other, and the only issue is you'd lose power in heating the extra wire by an amount you couldn't detect, and you'd lose a LOT of power if they were the same gauge.

Wire is selected based on:
1) current - a minimum wire gauge is needed for any given current.
2) voltage drop - larger than 1) might be required if the voltage drop results in excessive loss.

Risk is presented when 1) isn't followed.

The best (and pretty much only) way to "blow up" your system in this context is to exceed the voltage of your charge controller with your array Voc in cold conditions.

 

[whereitsat42]

Technically you were. Your approach would have made the panel 2 feet away with notably longer cables to meet your criteria.



LOL... I've definitely given you enough to draw your own conclusion. You could have 2 feet on one end and 500 feet on the other, and the only issue is you'd lose power in heating the extra wire by an amount you couldn't detect, and you'd lose a LOT of power if they were the same gauge.

Wire is selected based on:
1) current - a minimum wire gauge is needed for any given current.
2) voltage drop - larger than 1) might be required if the voltage drop results in excessive loss.

Risk is presented when 1) isn't followed.

The best (and pretty much only) way to "blow up" your system in this context is to exceed the voltage of your charge controller with your array Voc in cold conditions.

Super, thank you! (And sorry for being so questiony, just want to make sure I don't screw it up! Happy holidays!)

 

[sunshine_eggo]

Super, thank you! (And sorry for being so questiony, just want to make sure I don't screw it up! Happy holidays!)

You're welcome. No worries. Same to you!