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twinboat · 04-24-2015, 07:26 PM

Does your trailer battery get charged thru the trailer plug? If it does just get a female connector and hook to the 2 correct pins, to you solar wires.

Since you are using a simple controller and 1 panel, there isn't going to be any current boost, so moving the controller won't make a difference.

Superslif · 04-25-2015, 01:08 PM

Quote:

The Renogy 100watt suitcase kit comes with a 15' cable that attaches to the battery with clips. Since I have a hybrid RV trailer, reaching under the bunk, unstrapping the battery box lid, attaching the cable to the battery posts would be uncomfortable to do with the bunk opened up. My thought was to "hard wire" a short cable from the battery to a Anderson type connector mounted on the frame. This run of wire would be no more than 12" or 18". long.

This way I could, when I need the solar panels, just plug the 15' cable into the Anderson connector on the frame, rather than playing with reaching in under the bunk. If I kept the wire gauge the same or large, do you see this greatly reducing the amps getting to the battery.

and

Quote:

John Hilley wrote: That would work well and would be good way to implement it. It would be even better if you moved the controller from the back of the panel to the trailer.

But moving the controller from the back of the panel to somewhere inside the trailer. Now I have to "fish" wire back out to the battery location. I don't think you would want to attach the controller anywhere outside due to the weather.

Quote:

Twin boat wrote: Since you are using a simple controller and 1 panel, there isn't going to be any current boost, so moving the controller won't make a difference.

Are you sure?

I'm just trying to make this as simple as possible where if I need to use the solar panel, it will only be 5 minutes or less to set up.

twinboat · 04-25-2015, 03:38 PM

A PWM controller is nothing more then a fast switch , that keeps turning on and off, to keep your 17 volt panel from overcharging your battery. It keeps it within the range of 13.2 to 14.2 volts.

The 100 watt panel can produce around 6 or 7 amps. That's what goes into the controller and goes out.

If you had 2 panels, in parallel each panel would hook to the controller input and the output would double. In that case you would need bigger wire going to your battery "OR" move the controller closer to the battery and make 2, longer wires from the panels.

"OR" add a junction box, near the panels and, again, use bigger wire to carry the doubled amps to the controller.

This is where many people loose power. They don't use big enough wire from the roof top junction box to the controller.

I avoided running bigger wire, by hooking up, my 3 panels, in series. The amps don't triple the volts do, but I don't need bigger wire for that.

The MPPT controller converts the 51 volts back to battery charging volts at 3 times the amps. That is where I need the bigger wire and be closer to the battery.

It's actually all math, that is available everywhere.

Imurphy907 · 04-25-2015, 09:24 PM

I like portable panels. But to get the most out of them you need a fixed mount controller. The controller needs to be very close to the batteries. What you need to do is size the wires from the panels to the controller properly. Having the panels connected to the controller then running thru 25' of wire to the batteries will not work unless you are very large wire.

If you have a 100 watt panel with a output voltage of 18VDC thats 5.5 Amps
5.5Amps at 25' requires 6AWG wire. At 50' you should have 4AWG. Not impossible. But the kits likely come with way smaller wire. This will keep you under 1% loss and actually get charged batteries.

twinboat · 04-26-2015, 01:30 AM

Imurphy907,

Why does it change, when you move the controller?

So what size wire do you use from the panel to the controller ? It's the same watts.

5.5 amps from the panel to the controller and 5.5 amps from the controller to the battery.

4 gauge wire to carry 5.5 amps is a bit overkill IMHO.

marcham · 04-26-2015, 07:36 AM

Keep in mind that a 25' run to the battery is a 50' loop for the wiring. 5Amps @13.8V @50' for 1% Vdrop = 8 gauge. Should you add another panel in the future now you're looking at 4 gauge.

My trailer came pre - wired with a 18' run of awg8 (36' loop) from the controller install area to the battery. No complaints with a single 100w panel and I certainly won't upgrade the wiring if I add another.

If the panel has a controller on the back I'd just leave it there for simplicity. I'd be concerned about theft or wind damage though. Is 0.2 V worth the extra effort for a portable setup?

twinboat · 04-26-2015, 08:12 AM

All of this, is why, with the MPPT controllers, more systems use higher voltage panels.
My boat has 3, 36 volt, 225 watt panels, in series. My 8 ft run, uses 12 gauge wires.

SkiSmuggs · 05-17-2015, 03:59 PM

Quote:

Originally Posted by Superslif

See if this makes sense:

The Renogy 100watt suitcase kit comes with a 15' cable that attaches to the battery with clips. Since I have a hybrid RV trailer, reaching under the bunk, unstrapping the battery box lid, attaching the cable to the battery posts would be uncomfortable to do with the bunk opened up. My thought was to "hard wire" a short cable from the battery to a Anderson type connector mounted on the frame. This run of wire would be no more than 12" or 18". long.

This way I could, when I need the solar panels, just plug the 15' cable into the Anderson connector on the frame, rather than playing with reaching in under the bunk. If I kept the wire gauge the same or large, do you see this greatly reducing the amps getting to the battery.

This is exactly what I did. I found battery cable with rings on one end and Anderson connectors on the other (Battery Stuff, I think), put the rings on the battery studs and left the Anderson end hanging out of the battery box (inside a battery compartment. I just connect and place my panels in the sun.
Link to cable: http://www.batterystuff.com/battery-...ga4ringSB.html

Superslif · 05-18-2015, 07:02 AM

Thanx everyone. I ordered the 100 watt Renogy suitcase set-up off Amazon last week. Will have to wait till it arrives to see what is included as far as connectors.

Superslif · 06-04-2015, 06:23 PM

Received the Renogy suitcase (100watt) solar kit about two weeks ago. Seems to be very solid construction. The legs needed to have the bolts tightened up. I didn't like the way when closed the metal legs hit the glass on the back of the panels. I'm going to put some felt on the legs where they touch the glass. The zippered case will serve its purpose.

Reed Cundiff · 06-05-2015, 01:18 PM

Agree with Twinboat concerning higher voltages. To get best advantage of portable panels, you might have to set them 20 to 30' from RV (if you were parked under a tree for shade). Run 24 V and higher to controller and you can: run more watts, run further out, use smaller cable. We run 90 V from panels to conroller.
Reed and Elaine