Solar Panels

MC4 connectors are designed for series connections.
To use MC4 connectors in parallel, you need to buy a pair of Multibranch MC4 adapters and you need of course to have MC4 connectors on both panels. I think MC4 are soldered on the cable, so you have to either solder or crimp it somehow (after buying all the connectors and adapters).

Other than VERY rarely needed ability to quickly disconnect and re-connect the panels, I don't see any benefits in getting MC4 if you don't have it already.

I think RJ had success crimping his own MC4 but it is supposed to have a special tool.

I would tend to get a multiwire butt connector with heat shrink. I have used these and they are permanent and water proof.
http://www.waytekwire.com/item/32990/MULTIPLE-SEALED-WIRE-CONNECTOR/

Otherwise there is always the (ugg) combiner box.

Thanks for the information. If I don't have MC4 connectors should I get them to make the installation easier?

http://www.ebay.com/itm/A-pair-of-MC4-Branch-Solar-PV-Connector-Parallel-/280564405609?pt=LH_DefaultDomain_2&hash=item4152f11569

smkettner wrote:
If the existing panel has MC4 connectors you can get parallel connectors to make it plug and play.

Available in MC3 or MC$

smkettner wrote:
If the existing panel has MC4 connectors you can get parallel connectors to make it plug and play.

These are available in MC3 or MC4

If the existing panel has MC4 connectors you can get parallel connectors to make it plug and play.

I have 10 gauge wire between the solar charger and the batteries. I think this is adequate.

RJsfishin wrote:
You are talking 10-12 amps on a good day. How undersized could the wire be ???
And even if it was 14 gage instead of 10 gage, what we loose, 1 amp ??

Assuming 200 watts and 20 feet of wire, you lose about one volt and roughly 11 watts between the panels and controller. About 6% voltage drop. Add that to the losses between the controller and batteries, which could be significant.

The NEC states voltage drop should not exceed 5%, but in solar systems even that is way too high, IMO. By saving a couple of bucks on wire you end up throwing away watts and amp hour capacity. Do you still get a charge? Yes, probably. But not a full charge, and after paying for x number of watts and x number of amp hours, why throw away any of that to save a couple of up-front bucks on wire? No thanks.

If you have a 10 amp controller, it will get maxed out by the 100 watt panel, so you could not install a second 100 watt panel. Yet if you get a new 100 - 150 watt panel, and install another 10 - 15 amp controller, no worries, both cab be connecte to the same battery, and each will charge at it's maximum capaicty, until it reached the controller max battery set point, then both will either reduce ampeage to the battery or shut off until the battery voltage is lower.

SunElec.com

SolarOnSale.com

Fred.

Simplygib wrote:
Get the controller make and model, then the wire size and estimate the wire length. Post it here, you'll get plenty of suggestions.

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