Shortening solar panel leads

[Rob Littiken]

Can't decide if I'm getting too picky on this. Just installed 20 Evergreen 220W panels 10ea in series. The panels come with pretty long leads with MC connectors. When your connect them together you have around 3' extra between each panel. If I buy all new MC connector and shorten the leads it will eliminate nearly 60' of line.

Anyone else ever done this? Is it worth it? Am I crazy? Looks like it would improve voltage drop by about .7%

Pondering,
Rob L

[Ralph Day]

Hi Rob
Things to consider: Would altering the leads void your panel warranty (likely). Would the re-done connector be as good as the factory done job?(don't know).

Some small black tie wraps to coil and keep neat the excess lead length would be cheaper and keep your warranty valid.

Just my thoughts.

Ralph

[Rob Beckers]

Rob, in case you posed that as a question, here's the answer: "you're getting too picky!". :nuts:

Running the numbers, 60 feet of wire with 8.5A current (that's about peak for regular 60 or 72-cell module), I get a loss of 6.9 Watt (0.16%) for 12 AWG, and 4.3 Watt (0.10%) for 10 AWG. Most panels use 10 AWG these days.

In short, you're saving nothing, making lots of work for yourself, spend money (MC4 connectors aren't all that cheap), and unless you have a good MC4 crimper and good connectors run the risk of bad connections.

By the way, I'm not in favour of coiling up excess wire (induction loops, lightning, maybe I'm being too obsessive), instead I like to run it flat against the rails. Get some black UV-resistant tie-wraps with a stainless tooth in it (we get them from Westburne in town here), they should last a good long time. Try not to put strain on the leads as they come out the j-box when you tie them down, that's another issue waiting to happen down the line.

-RoB-

[Rob Littiken]

Thanks for the answers. It's nice to be kept grounded. I've got plenty of other projects to keep me busy besides shortening wires.

Thanks,
Rob L

[Rob Beckers]

For kicks and giggles: I just got off the phone with a PV installer who's hooking up 120kW on a roof. His problem is the opposite; the panels are installed in landscape and were supposed to be hooked up in rows. Unfortunately the panel manufacturer changed the length of the leads on the panels since the last time, and they are now about 2" too short to connect panels in landscape together.

The stupid things manufacturers will do to save 10 cents...

-RoB-