Exterior solar plug-in

[tdf-texas]

Originally Posted by Jim Bennett

My local solar store said I definitely should. I realize my fixed panels totalling 240W are not anywhere near 100% efficient, but when I was to add my 80W portable that I can aim, it would have a better efficiency.

Just curious, I have been meaning to ask you. How do you hook up your 18v portable to your 36v roof mount solar panels? Are you using more than one solar controller?

My understanding is that using one MPPT solar controller, if all the panels are the same volts out but different amps -connect using parallel. If all the panels are the same amps but different volts - connect in series. Any other combination would limit the power out of the panels.

http://solarpanelsvenue.com/mixing-solar-panels/

Of course, if you are using two solar controllers (and they don't fight each other), then all is good.

[Brian B-P]

Originally Posted by alanmalk

... "MMPT" type controller.

"MPPT" for Maximum Power Point Tracking (just in case anyone is using this for search term)... but we know what you mean.

[Jim Bennett]

Originally Posted by alanmalk

You have a total wattage that could do some damage to the batteries if not controlled in some way. Plus since you have wired the system in series to produce 36 volts you would benefit greatly from the "MMPT" type controller.

Yeah, I definitely used an MPPT controller in my application. In my quest to learn solar you put a few things in the way that got me understanding them. The fellow I deal with at the local solar shop is quite good too.

Originally Posted by tdf-texas

Just curious, I have been meaning to ask you. How do you hook up your 18v portable to your 36v roof mount solar panels? Are you using more than one solar controller?

My understanding is that using one MPPT solar controller, if all the panels are the same volts out but different amps -connect using parallel. If all the panels are the same amps but different volts - connect in series. Any other combination would limit the power out of the panels.

Mixing solar panels – Dos and Don’ts • SOLAR PANEL SECRETS EXPOSED

Of course, if you are using two solar controllers (and they don't fight each other), then all is good.

My GoPower 80W panel is actually two 40W panels, so I rewired them in series as opposed to parallel so the output is 36V. I also bypassed the onboard solar controller. Because I used MC4 connectors, I can still quickly set it up as a stock 18V set with the controller.

You do need to have the same voltage feeding the controller for ideal performance, and I wired two pairs in series , and then paralleled the 36V outputs to the controller. My understanding is that if you supply differing amperages to the controller in series, it will be at the current of the lowest one.

[rubicon327]

Originally Posted by Jim Bennett

My GoPower 80W panel is actually two 40W panels, so I rewired them in series as opposed to parallel so the output is 36V. I also bypassed the onboard solar controller. Because I used MC4 connectors, I can still quickly set it up as a stock 18V set with the controller.

You do need to have the same voltage feeding the controller for ideal performance, and I wired two pairs in series , and then paralleled the 36V outputs to the controller. My understanding is that if you supply differing amperages to the controller in series, it will be at the current of the lowest one.

For those that need a visual aid
http://www.escapeforum.org/forums/f8...tml#post198081

[Jim Bennett]

Originally Posted by rubicon327

For those that need a visual aid
http://www.escapeforum.org/forums/f8...tml#post198081

Thanks, I had forgotten about that drawing I did. I did it primarily for myself so I could visually see what I was thinking of doing.

[tdf-texas]

Originally Posted by Jim Bennett

My GoPower 80W panel is actually two 40W panels, so I rewired them in series as opposed to parallel so the output is 36V. I also bypassed the onboard solar controller. Because I used MC4 connectors, I can still quickly set it up as a stock 18V set with the controller.

Since my Lensun 100w portable can't be split like that, it looks like I'm stuck with 18v parallel for all my panels. I'm installing four 50w panels on the roof with a Zamp port for the portable. If it looks a LOT like your's when it's done, it's because I copied your installation as much as the layout of a 21' would let me. Using 36v would be a help on the voltage drop but it can't be done with the portable I own.

[Jim Bennett]

Originally Posted by tdf-texas

Since my Lensun 100w portable can't be split like that, it looks like I'm stuck with 18v parallel for all my panels. I'm installing four 50w panels on the roof with a Zamp port for the portable. If it looks a LOT like your's when it's done, it's because I copied your installation as much as the layout of a 21' would let me. Using 36v would be a help on the voltage drop but it can't be done with the portable I own.

Is there no exposed wire between the panels on the portable? It was fairly easy to rejig on my GoPower Panel.

I would bet that the savings in voltage drop I see using a lower amperage is quite minimal.

[tdf-texas]

Originally Posted by Jim Bennett

Is there no exposed wire between the panels on the portable?

No and to make matters worse, it's a three panel portable. But it does fold up small and fits in my wardrobe closet.

[alanmalk]

Originally Posted by Brian B-P

"MPPT" for Maximum Power Point Tracking (just in case anyone is using this for search term)... but we know what you mean.

Yes, of course - MPPT, not MMPT. I'm glad somebody knows what I mean 'cause sometimes I don't know myself.

--
Alan

[h2owmn]

Only 15 days til orientation!

My lensun folding panel arrived yesterday. My 17a has a zamp port installed in the back of the trailer near the batteries, and no rooftop solar. I will have 2 6v batteries.

--5 questions--

1. For wire...10 gauge recommended? What I am looking at is at powerwerx Red/Black Bonded Zip Cord Easy ID Low Voltage Cable

2. How many feet recommended? 25, or?

3. I will need a controller to be put somewhere. Controller recommendations?

4. Does the controller go just outside the battery box? On the inside near the port?

5. (only sorta related) Trademasters will do my vehicle 7 pin wiring. Should I specify what gauge wiring? (it has a 4 pin but according to trademasters, is not plug and play.

Thanks!