Forum Discussion

obiwancanoli's avatar
obiwancanoli
Explorer
Sep 29, 2020

Connecting Portable Solar Panels

As I've been exploring an upgrade of my entire electrical system, I'm contemplating adding additional solar, and looking at options.

I have plenty of room on the roof for a few more panels, though I probably need only 2, at around 300-600W added to my current 480W panels, and a 120W portable. Four Battle Born Lithium batteries are probably installed by now, along with a Victron 100A/50 MPPT controller, and 712 Voltmeter. Given those hot days when you'd prefer to be under some shade, it seemed having a portable would be prudent for those times when you need to be more judicious by having solar you can actually point at the sun.

Thus, I am thinking it might be prudent to add at least ONE portable, maybe up to 300W perhaps, and I had a couple questions for y'all... first, does it make sense for me to consider an additional portable, and if so, how long of an extension cord should I consider? Is 20 ft sufficient, or is 30 ft a more practical length?

Second, can two - or more - portable panels be tied together so that only one lead goes to the batteries? I've looked on Amazon, but amongst the multitude of pages I must sift through, I confess my patience was challenged, and I gave up before having any success in finding a 2-into-1 fitting that combines the two...
  • madjack60's avatar
    madjack60
    Explorer
    Sep 29, 2020
    Ebay has lots of 2 into 1 upto r into 1 spliters. You may want to check if your charge controller can handle all the extra wattage.
  • Lwiddis's avatar
    Lwiddis
    Explorer II
    Sep 29, 2020
    Wouldn't the weight of a 300 watt "portable" solar panel be 50-60 pounds?
  • 2oldman's avatar
    2oldman
    Explorer II
    Sep 29, 2020
    obiwancanoli wrote:
    can two - or more - portable panels be tied together so that only one lead goes to the batteries?
    To the controller.. sure. You don't need special connectors, just wire them up yourself.
  • obiwancanoli's avatar
    obiwancanoli
    Explorer
    Sep 29, 2020
    pianotuna wrote:
    you will soon tire of deploying portable panels.


    That may be, but if it's the only way to charge the batteries, best to be able to tap into the sun
  • Lwiddis's avatar
    Lwiddis
    Explorer II
    Sep 29, 2020
    I'd get very tired quickly moving around a 50 to 60 pound panel. And where would you store it?
  • jaycocreek's avatar
    jaycocreek
    Explorer II
    Sep 29, 2020
    Portable solar is about the only way I could use solar camping in the deep forest hardly ever in the sun.As far as how many feet of cable,it depends on where your camping..I am using about 30ft or just shy of it in this pic.

    As far as always moving the panels,you don't have to but if you do,you get the most watts to the battery..Just laying my panels flat like it would be on the roof,I lost a bunch of watts..LOL

  • 2oldman's avatar
    2oldman
    Explorer II
    Sep 29, 2020
    obiwancanoli wrote:
    how long of an extension cord should I consider? Is 20 ft sufficient, or is 30 ft a more practical length?
    The longer the cord the more loss. Consider a series hookup if much over 20'. A 300w panel will likely be 24v.
  • jaycocreek's avatar
    jaycocreek
    Explorer II
    Sep 29, 2020
    2oldman wrote:
    obiwancanoli wrote:
    how long of an extension cord should I consider? Is 20 ft sufficient, or is 30 ft a more practical length?
    The longer the cord the more loss. Consider a series hookup if much over 20'. A 300w panel will likely be 24v.


    While this is true,it can easily be a non issue by buying quality portable solar panels with 23-25% efficiency compared to the cheaper 18% or so..Some of the top names are not the top performers.

    If the op is serious about portable solar,I strongly suggest he looks up Hoboteck on youtube and watch as he compares the portable solar panels one on one/side by side..Quite interesting...
  • pianotuna's avatar
    pianotuna
    Nomad III
    Sep 29, 2020
    obiwancanoli wrote:
    pianotuna wrote:
    you will soon tire of deploying portable panels.


    That may be, but if it's the only way to charge the batteries, best to be able to tap into the sun


    I dislike generators, but relying 100% on solar may not be wise.

    If you are in a class C or class A with a v-10, it can safely be idled to recharge the batteries. Equip it with a dc to DC voltage boost device, and limit current to 1/4 of maximum alternator output.

    If not equipped with a V-10, then a small generator may be a good back up source.

    I do get six amps of charging at solar noon in leafy shade.

    I do get three amps of charging at solar noon in the rain.

    My solar farm is tiny at 256 watts, in comparison to your rather magnificent system, but now that I'm back to part time, it will be more than adequate when I upgrade to 600 amp-hours of SiO2 jars. My OEM system had ~437 amp-hours usable. (875 Amp-hours, total). I had no generator at all for 5 years. I never had to idle the v-10 in those 5 years. I ran out of fresh water before I ran out of power--and I cooked 100% electrically.

    You seem to have deep pockets--so why not max out the solar panels on the roof--they are the cheapest part of the system, in terms of cost per watt. My cost per watt was $5.50 in 2005, for the panels.

    Then, if you find you need them--buy some portable panels.

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