Safe current for MC4's in a series installation

[Komotion]

Hi all,

OK I'm having a brain fart. It could be the surprisingly hot autumn sunshine here in Mallorca! I'm busy installing 8 new 175w panels on my sailboat. There are two arrays of 4 panels each, connected in series. Each array goes to it's own Victron MPPT controller. Here's where I'm thinking myself into a tangle: MC4 connectors are rated at 30A, right? Do I need to worry about my connections in this series application or (as my brain is mostly telling me) is it just the voltage that has gone up across the array (4x23.9Voc=95.6Voc) while the current stays exactly the same?

The total power of each array is 700W (4x175) so as P=I.V, that leaves just 7.3A (700W/96V) but I just can't shake the feeling I'm missing something! For one thing, 16 gauge wire (good for 10A) just LOOKS way too thin for this application! I'd probably go up to 12 or even 10 to avoid voltage drop, but still.

What am I missing!?!?

(Wires in the pic are just for commissioning.)

Thanks,

Mike

 

[sunshine_eggo]

Hi all,

OK I'm having a brain fart. It could be the surprisingly hot autumn sunshine here in Mallorca! I'm busy installing 8 new 175w panels on my sailboat. There are two arrays of 4 panels each, connected in series. Each array goes to it's own Victron MPPT controller. Here's where I'm thinking myself into a tangle: MC4 connectors are rated at 30A, right? Do I need to worry about my connections in this series application or (as my brain is mostly telling me) is it just the voltage that has gone up across the array (4x23.9Voc=95.6Voc) while the current stays exactly the same?

Yes.

You need only consider the Isc value of the panels.

 

[rhino]

MC4 connectors are rated at 30A, right?

"MC4" does not have a designated ampacity rating. You'd have to either check on the connector itself to see what the ampacity is or find data sheet on it. You can get MC4 connectors that are rated for 70A from ABB in their catalog for example: https://library.e.abb.com/public/3cb34380a4374eaaabc2a817c85e1a1e/1SNC160040C0201_ SolutionSeries-MC4-EVO2 PV Connectors_EN_.pdf