Questions about solar power

[Tim Wood]

I'm thinking about using this:Go Power! GP-PWM-30 30 Amp Solar Regulator for about 112.00 or this :MPPT Tracer1210RN Solar Charge Controller which is 68.00. Hard to believe that I can get the mppt cheaper, but it might not be better either. And will more than likely go with the Grape 105 panel. Making my own kit up like some others have done. That way I have what I want and nothing I don't, unless it doesn't work of coarse. And don't forget everything is subject to change:

Conrad, I really like your idea of riveting the z to the panel. I will probably borrow that idea, easy does it.

[stev]

Thanks..
I ordered these to mount my panels..
Solar Panel Z Bracket Mount Mounting Set RV Boat Off Grid | eBay

[Tim Wood]

Stev, Those look like nice brackets. I'm going to start ordering things tomorrow.

[MCDenny]

I posted this on Night Sailor's "solar install" thread but thought I'd duplicate it here.

My question is "do I need an off-on switch for the solar panel?"

My panel will be on the roof most of the time but will slide out of the roof top rack to go in a portable frame on the ground if I'm parked in a shady spot. I'll be able to disconnect the MC4 plugs connecting the panel to its harness and I have a difficult-to-access circuit breaker that disconnects the +12 battery terminal from everything but I'm really wondering if there is a reason to have a convenient off-on switch indoors.

Is there any routine (not maintenance) reason to turn off the panel?

How about when the battery charger is plugged in?

How about driving when the tow vehicle battery is connected in parallel to the trailer battery?

I'm starting my solar install tomorrow and this is the last question I have (right now).

[Night Sailor]

No, you can leave it connected. I just have a fuse between the panels and the battery. They recommend placing the fuse close to the battery.

If you want to work on the pale circuits, cover the panels, disconnect the battery.

[Night Sailor]

You can rub the battery charger at the same time.

You can leave it connected to the car. This might draw down your house bank if you have a bad cell in you car battery. With solar , it will help keep your car battery topped up.

[Night Sailor]

If you have a good charge controller you can leave it connected all the time.

[Mike Magee]

The controller's specs will tell if it prevents power from drawing backward from battery to panel overnight. Good controllers like Morningstar do this. Lack of reverse draw prevention would be the only reason I know of to have a switch.

[peterh]

Larger rooftop systems that run above 50v must have interrupters in the series wiring between panels, because above 50v the skin's electrical resistance value hits its breakdown point, and current can make the jump to that nice, salty, conductive fluid found just below your skin. Unless you're connecting four or more panels in series you won't run into this.

MC4 connectors are not, by the way, intended to be connected and disconnected frequently. You might be better off getting SAE 2-pin connectors and using them. They're designed for quick connect and disconnects.

I've got one of these for the side of our Surfside trailer to connect our movable panel set and 2, 25 foot 12g SAE 2-pin cables to connect the panels.


Picture from
73 SAE Connectors, Plugs, Sockets & Cords

[blodn1]

Most of the wiring diagrams I've seen show the switches at either side of the controller so that one or both sides can be isolated.

[Night Sailor]

My uncle tells me camping in Alaska requires parking in the sun to avoid the bugs. Most places parking in the shade is preferred, so a remote panels make good sense due to their flexibility. I opted for permanent installation for convenience and security.

[stev]

Regarding the SAE connectors.
Thanks for the link. Good idea.
Wonder if there is any that are 10 gauge wire?

[ruscal]

Originally Posted by peterh

MC4 connectors are not, by the way, intended to be connected and disconnected frequently. You might be better off getting SAE 2-pin connectors and using them. They're designed for quick connect and disconnects.

Peter,
I have a 2 panel portable system that I left the MC4 connectors on the panels due to warranty requirement. I could have made short adaptors with MC4 to
Anderson connectors, but thought having 2 connectors seemed bulkier and more resistance etc. I always plug in the MC4 before any load is connected to eliminate arcing. The locking feature of the MC4 is not needed in my application, so I could remove the locks I suppose to avoid the need for the release tool.
The Anderson's work so well I may be better off just making the adaptor, so my extension cords would be bi- directional and I could then run both cables to one panel if I needed extra length to get out of the shade.
Russ

[peterh]

Originally Posted by Night Sailor

. . . I opted for permanent installation for convenience and security.

Our two trailers have 100w of fixed, roof-mounted solar, and we really like that. No fuss, no muss, no hassle, and very minimal theft concerns. THe trade-off is less power when you're parked in the shade.

Less power, but not no power. To suppliment our panels when we're in a shady spot I built a 40w, suitcase-sized satellite unit with an integrated 10-foot SAE 2-Pin cable from two aluminum-framed 20w mono panels. When folded, the cable and extension cables, and its disassembled PVC pipe stand tuck neatly in the space behind the panels.

In most cases, the 10' cable is too short, and I have to use one or both 25' extension cords. Having two shorter cables instead of one long one helps me keep voltage loss to a minimum.

[Night Sailor]

Peter what sort of power output are you seeing with your roof punted panels? I the Sun and the shade?

And what do you pick up with the remote panels, which I presume are angled more perpendicular?

Any pictures?