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Solar charging system for P3P batteries?

Discussion in 'General Discussion' started by gringorio, Feb 22, 2016.

  1. gringorio

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    Since I am pretty ignorant when it comes to watts, voltage, electrons etc, I thought I'd turn to the brainiacs who inhabit Phantom Pilots to ask how many watts a solar panel would need to be to charge one P3P battery in the same amount of time the wall charger does?

    I am thinking of those times like a long back-country road trip or kayak expedition where being able to charge the P3P batteries would make it worth while to take it along.

    Anyone with the right combo of knowledge able to pipe in?

    Thanks!
     
  2. mikeve

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    With the P3P you have the 100 watt charger and that can charge the 68 watt-hour battery in about an hour. This means the charger is about 70% efficient. Best bet is to find a good cig. lighter charger, get the specs on that and then find 12 volt solar array that can provide the power that the charger can deliver. 12 volts x 8 amps = 96 watts. After 1 hour, the charger will have delivered 96 Wh. At 4 amps, it'll take 2 hours to charge.


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  3. adfischer

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    The charger for the P3P is 100 watts. The reality is you might get 50% efficiency (if you are lucky and depending on where you are located) so you are up to a 200W panel. You will also need an inverter to give you the proper voltage. You will also want a battery to power from rather than a solar panel so your power is consistent. You also need a charge controller to manage the battery. So basically what I'm telling you is, it is impractical to try to charge from solar. You are probably better off in terms of weight, size, and cost to just buy extra batteries.


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  4. Ralph M

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    Well, using commonly available panels (like this one from Harbor Freight: 15 Watt Solar Panel) it would take four of them to generate 60 watts - roughly the equivalent of the charger that comes with the P3A - and that is at peak output. Four panels would be roughly 36 inches tall and 50 inches wide, and would weigh about 40 lbs total. Setting aside the fact that you'd need a conversion of the power from the panel from 12 volts to roughly 17 volts, you might be able to recharge a P3 Intelligent Battery in about 90 minutes at mid-day. But you sure as heck are not back-packing this gear. :)
     
    #4 Ralph M, Feb 22, 2016
    Last edited: Feb 22, 2016
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  5. eaglegoaltender

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    Good point Ralph - how are the invites doing for your "fly-in"?
     
  6. Ralph M

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    Brief segue off-topic: I've had a few folks email me. I am currently focusing on Sunday, March 20th. Even if there is just a handful of us, I think we can enjoy ourselves. Expect me to send out an announcement next weekend.
     
  7. Air Ontario

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    Watts = volts x amps and I believe the panel I have is 100W and 17.5v
    Amps= 100W/ 17.5V = 5.7A

    5.7A x sun hours=total daily output@max efficiency which you won' t get.
    Only you know what amount of sun you have and for how long each day.
    But 4 hours at 5.7A=22.8A
    2 hours @ 5.7=11.4A
    So a total daily output of 34.42A to put in the battery that day.

    I don't have the battery in hand to see the storage capacity.......
    Anyway that should get you started until a more learned colleague comes along on something besides an iphone.

    Edit... See? I type too slow...........
     
    #7 Air Ontario, Feb 22, 2016
    Last edited: Feb 22, 2016
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  8. Energy Guy

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    Adfischer & Ralph are pretty much right on. In lieu of a large and expensive solar charger, you could get an inverter to plug into your accessory outlet in your car. That's what we use to charge on the road. I plug it in while driving and when parked. Don't drain your car battery so that you end up stranded in the boonies, though.:cool:
     
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  9. Sagebrush

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    If you are going to use an inverter (12v to 120v) so you can plug in your stock DJI charger, you'll lose a lot of efficiency since the stock charger then has to convert it back to 17V DC.

    I think you'd be much more efficient to go with 12v panels and a 12v converter like this:
    http://www.amazon.com/Yosoo-Charger...54&sr=1-11&keywords=dji+phantom+3+car+charger

    This converter changes the vehicle's 13V DC to the 17V DC needed by the charger. Much more efficient.

    How practical? I can't say. I built a folding setup out of two 30 watt panels (with a charging controller) to keep my camper battery charged. I think I put $130 into it. It works well.

    I've bought panels and controllers from Solarblvd.com, cheap prices and good products.

    S
     
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  10. Ralph M

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    You will have to science the **** out of this...

    martian.jpg
     
  11. gringorio

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    Thank you, all of you for your input and numbers-explanation! I see now that the best bet for sea kayaking would be extra charged batteries. For the car, a simple 12V charger.

    Though, when I get a truck or camper van, it looks by the numbers that if I get a system capable of charging Phantom 3 batteries, that system will also be able to charge a laptop, camera and my cell phone batteries.

    A future kayak trip will probably be under 10 days so it seems more affordable to buy extra batteries for that kind of trip. I'm guessing I'll have to get a Pelican case to store the quad on the kayak deck!

    Thanks again for your quick response!
     
  12. Ralph M

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    FYI - I have one of these, and recently had the opportunity to give it a workout on a road trip. It was ok, but from about 25% charge to 100% took the better part of two hours, with the car running. It got me through the day (five flights on two batteries), but the lesson I learned was that I needed more batteries.
     
  13. BigDun

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    Based on those numbers, am I correct in concluding that this solar charger from Amazon would charge a P3P battery in about 4 hours under ideal conditions?

    Amazon.com: SUAOKI 60W Portable Sunpower Mono-Crystalline Folding Solar Panel With DC 18V and USB 5V Output Charger for All 5-18V Electronic Devices: Cell Phones & Accessories