Backcountry charging multiple devices directly from panel?

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  • chuckthompson
    Junior Member
    • Jun 2021
    • 2

    Backcountry charging multiple devices directly from panel?

    Obligatory first time poster disclaimer, apologies for any novice questions.

    So, I’m working on an off the grid film and photo production in the coming months (well, if covid doesn’t say otherwise) and I’m brainstorming my charging setup for still cameras, motion cameras, drones, phones, and various other USB powered products. The most significant hurdle to the trip is that it’s all human powered (i.e., where we’re filming there’s no cars…or even horses) so everything must be carried on our (read: my) back. Woof...not to sound like a weight weeny but if we can trim ounces we will.

    I feel pretty confident in panels I’ve settled on (either P3 of PowerFilm, 100-150W, 12-24VDC, 5-8A), as they’re the lightest on the market as far as I can tell and I’ll likely use some sort of battery bank of 100-200WH—heavy but don’t see a way around it if things have to be charged.

    That all said, hypothetically, I was curious on people’s thoughts on skipping the battery on certain parts of the trip (we’ll have a bigger base camp and then likely be out for 1-2 nights in forward camps when the weather lines up, meaning it has to be clear for what we’re filming). I’m trying to figure out a system so all batteries can be charged off of USB directly from the panel (am I crazy!?). My thought here is not only trimming the weight of the battery, but also achieving better efficiency by not charging panel to battery to device, just panel to device.

    From what I’ve read there’s no shortage of issues/risk with this but, again, staying hypothetical. It seems like I’d need a MPPT with several USB ports or another sort of charge controller that can distribute the incoming solar charge to several devices which will likely have slightly different voltage requirements. Worse case scenario would be damaging a battery because the charge isn’t regulated from the panel. Ideally, I’d be able to charge 3+ batteries/devices simultaneously that have modest power requirements.

    I’ve found a few different MPPTs with USB options, but they’re all designed to charge some sort of battery as well (as far as I can tell), and not specifically designed to distribute the entire input from the solar panel to different ports on or near the MPPT itself. Or maybe I’m missing something?

    I’ve also looked at Anker’s hubs, which could be an option, but if the connection from the solar is MC4, APP or SAE it seems like a lot to get from those interfaces to a USB C and then splitting from there…just seems like you’d lose a lot of power in the process?

    Finally (and helpfully!) cost isn’t much of an issue, within reason, as I’ll be passing all expenses onto the production company. So any and all ideas, however crazy, are much appreciated.
  • Mike90250
    Moderator
    • May 2009
    • 16020

    #2
    Well, that's a tough question. But I might have an answer.

    I'm thinking of using a 12V Li automotive jumpstart pack. Charge it from your solar panel, and let it's internals power it's own USB ports. The pack I have, has 2 USB ports. The jumpstart pack has a 12V charger, so you can charge it from a running car. What an unregulated PV panel will do to it, I don't know.

    The other thing, is count up all the watts stuff uses. You need to find out if your gear consumes 468 watt hours. and your panel can only harvest 400wh in a day.

    Alternatively, you can use non-rechargable primary batteries. All depends on the weight of extra batteries, vs an extra PV panel and jumpstart pack

    Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister

    Comment

    • chuckthompson
      Junior Member
      • Jun 2021
      • 2

      #3
      Thanks Mike!

      Appreciate the feedback. Will definitely look into that (and luckily have plenty of time to test before hand).

      Am I correct in assuming that your calculation of 400WH is based on 8hrs of daylight and an average of 50% efficiency in the 100W panel in real life conditions? Will also total up all watts.

      Also found this adaptor that might work? Not sure if anyone has experience with this brand though:



      Again, thanks for the feedback! Truly appreciated.

      Comment

      • Mike90250
        Moderator
        • May 2009
        • 16020

        #4
        Nobody gets 8 hours of usable sunlight, except maybe at the equator . 6 good hours is outstanding - I can get that at Burning Man, with hourly adjustments to track the sun. When the sun is low in the sky at sunrise and sunset, the thick atmosphere blocks a lot of energy, 9am -3pm are generally, the productive hours. (changes with daylight savings time)

        The 400wh was just a random number.

        100w panel @ 50% for 6 hours is 300wh. Solar power is not very dense. Any shade is BAD, even a fallen leaf on the panel is BAD for harvest

        Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
        || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
        || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

        solar: http://tinyurl.com/LMR-Solar
        gen: http://tinyurl.com/LMR-Lister

        Comment

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