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Phantom 2 field charging

Discussion in 'Phantom 2 Discussion' started by landed, Jan 13, 2015.

  1. landed

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    Hi I have seen that dji do a very expensive car charger now - but its not wise to use your own car battery for this kind of load a 12v leisure battery is designed to be drawn down and last must longer however this is besides the main issue I have.
    The phantom 2 battery is classed as 11.1v but when charged is more like 12.7v so could a 12v battery ever fully charge a 12.7v battery ?
    11.1 volt battery = 3 cells x 3.7 volts (3S)

    so is the phantom battery 11.1v or 12.7v ? Answered my own question here ..

    Most LiPo/Lion cells are 3.7V nominal (4.2V max and 3.2V min) So the nominal reading is what is showing... SO can this video be on the mark (2 videos in fact)

    https://www.youtube.com/watch?v=CA1cWjFD1Cw

    I assume for a 5200mah battery for charging at 1C this means a charge amps of 5.2 ?
    So I would need a power of IxV 5.2 x 12.6v = 65 watts - I am thinking the mercury ex may not be up to this newer age of power supply. Or it simply charges at lower than 1C and just takes longer ? The above 1C charge rating would presumably take an hour ?
    at 2C or 10.4 amps x12.6v (should I use nominal figure or max V?) 131 watts power needed.

    at .5C 2.6 amps x12.6v = 32.76 watts but agonizingly 2 hours charge time ?

    Am I getting these rough figures right ? I could live with a 45 - 60 minute wait time.
    Is that possible from a 12v leisure battery..
     
  2. Mako79

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    Get an emergency jumper pack and cigerrete lighter 150w inverter.
    This means your car doesnt have to be on for charging
     
  3. RDCF550

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    Just like any other battery, a 12v car battery isn't really 12v. Your car's battery is closer to 12.6v at full charge, then around 13.8v to 14.4v when the car is running, to charge the battery.

    Your car battery has hundreds of amps available for starting, while it should not have that kid of load placed on it for an extended period, you'd have to be out there all day charging battery after battery after battery to put a dent in that thing charging the DJI batteries, or just have a crappy car battery to start with that was ready to fail, and you can always start the thing while recharging it.

    The Phantom 2 battery controls the charge rate, as the actual charger is built into the battery pack. You only need to give it 12.7v or a bit above and at least 4A (50W) for the battery to charge. So you can have a 50W or a 5000W power source and it will make 0 difference in the charge time, which can be closer to 2 hours for a battery that is run down completely.
     
  4. PhantomFanatic

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    Get a DC to AC inverter. Even a 1,000 Watt inverter will do. But, in case of a home power outage, a 2,000 Watt inverter can be hooked up to your car's battery. For TV's etc., a pure sine wave inverter is best. Plug your devices directly into the inverter so you won't have back feed into the electrical system.

    With an inverter, you can plug the DJI's battery charger into it and you will have a charged battery, in time.

    Edit: Yes, a standard car battery can easily handle this load and more. I've seen car batteries in the 14 VDC range. It depends on the battery and the voltage regulator, in the vehicle.
     
  5. landed

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    Thank you all for posting I have a much better understanding now and would feel more ok about using the cigarette lighter with an inverter and then using the standard charger.
    Its looking like I might need 3 batteries then if its always 1:20 to charge a phantom battery at 20% charge. To get a decent uninterrupted flight session for filming a subject.
    The inverter just seems like the easiest route and is so useful with the SUB port and being able to then use any appliance with a lowish power consumption.
     
  6. Crazykaktus

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    If I may share my 2 pennies worth here. I use my Phantom to cover MTB races and outdoor sporting events for television. Im in the field 90% of the time... i have 4 batteries but I kill them in under 2 hours. I basically always have one on charge and cycle them as they deplete to ensure that 60 min later I have a charged battery. First off the DJI car charger works well... But charges forever

    SO why not just use a standard high quality programmable lipo charger that can attach to your car batter via your cigarette lighter. All it will require is for you to make a cable that can attach to your phantom battery. They are simple to make.. You just need to spade connectors that attaches to the battery. I use a VISTA Power EV650. It powers from a 12V scource and pumps out up to 5A charge for anything from one individual lipo cell to up to 6 cell combos. It charges my P2 batteries from 30% to full in about 52 min.

    As for the continuous charging of batteries killing your car battery - that can and never will happen - Unless you drive a Smart car with a nano battery. I used to Race RC cars BIG time and had two chargers pumping over 5A charges into NiCD batteries all day. Never killed my battery. And even after a full day in the field charging each PH 2 battery at least once - Ive NEVER had my car battery die on me. I must add that I drive a Landrover with a pretty big battery to start with. A good quality inverter will cost you the same if not more than a TOP class high quality Lipo Charger.

    Hope this helps you
     
  7. badbrad97

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    You might need 4 batteries to run continuous flight. Your biggest problem is going to be heat. The batteries get hot when discharging and hot when charging. You will damage them if you keep them that hot for hours. Depending on how much downtime you have between flights, you will need time to let them cool off.

    Also check your motors for heat. If they are getting really warm you need to stop and let them rest until they cool off.

    I have had a couple occasions where I was filming almost non-stop for 3 hours and you really need to pace yourself and keep things cool. And I have 8 batteries.
     
  8. herein2014

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    I too have flown practically all day with no issues. I use the car charger from DJI and my truck's cigarette lighter does not shut off when the truck is off so I can charge when the engine is off, I also have an Optima Red Top for my car battery vs the stock battery which may be why I usually get recharge rates that are faster than advertised. On top of that I keep a car jump pack with a built in cigarette lighter socket in the back so that if I have to trek a ways into woods or far from where I parked I can put the used battery on the jump charger without having to return to my car.

    Lastly I never discharge a battery past 60% when in the field unless I'm filming some kind of an action scene that simply won't wait or its near sundown and I won't be able to fly again anyway; its my experience that the recharge rates of LiPo batteries are not linear; you will be able to recharge a 40% discharged battery more than 2x faster than an 80% discharged battery.

    If you do have a vehicle that shuts off the cigarette lighter when the car is off, its a simple matter to change the wiring to stay on all of the time, or wire up your own lighter socket. I could also just use the jump pack, but the cigarette lighter socket is more convenient, plus the jump pack needs AC power to recharge, vs. my truck which will recharge when the engine is running. They have some newer jump packs that can also be recharged by the car's cigarette lighter, so if you do a lot of deep woods or mountain treks you may want to go that route. Lugging the jump pack can be a bit of a pain though.

    A jump pack is great for boats too, on a boat you cannot afford to add anything new that will drain the batteries faster or you might get stranded in the middle of the ocean when the engine won't start so I never charge my batteries off of anything except a dedicated jump pack when I'm launching from a boat. I have never tried charging two batteries at once off of a jump pack, but I have considered it. I really don't care to spend another $120 on another DJI car charger especially since I'm considering getting the Inspire 1 once the bugs are worked out and it will accept a GoPro gimbal.
     
  9. herein2014

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    I am well aware of the mechanics of engines and have owned many boats. I have also towed back many a stranded boater who didn't realize their trolling motor, fishfinder, ship to shore radio, AM/FM radio, and livewell do not run off of air. And yes, alternators have been known to fail and second or even 3rd marine batteries have been known to not properly charge or hold a charge. When you are 20-50 miles offshore doing anything that could possibly jeopardize your return trip is irresponsible in my book.

    To me, charging my Phantom batteries using a power source that could literally mean the difference between life and death is completely foolish. Having a storm get between you and shore with no way to crank your boat is a sure way to end up on the evening news. I admit these are extreme scenarios but I've been boating over 20yrs and have seen it all. Nothing gets connected to the boat's battery unless it is critical to the boat's operation or the motor is running at all times.
     
  10. Crazykaktus

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    Your talking about a drone here - Not a boat - Thats out at sea. ANY Lipo charger will not charge the battery if the incoming voltage and amps is not correct to do so effectively and safely... Thats why its an intelligent charger.
     
  11. Ezookiel

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    I already have 3 batteries.
    From 20% left, to fully charged, my mains charger take 1hr 40 mins per battery.
    Each battery gives around 15 minutes flight time.
    If I was to finish battery 1 and put it on a charger in the car, by the time I finish batteries 2 and 3, that's only 30 minutes that battery 1 has had to recharge, and batteries 2 and 3 haven't gotten near the charger yet, so I can't see how 3 batteries is enough. First you'd need one charger for each battery, and you'd need around one hour 40 minutes worth of batteries (around 7 batteries) each with it's own charger, to cycle endlessly through them.
    You could speed things up by landing earlier, but then you're also cycling through them faster with the shorter flights, so however you look at it, you'd need quite a lot of chargers and batteries.

    You won't kill a good car battery charging a Phantom battery. Provided it's in good condition, and not some very tiny little thing out of a modern micro-car, you SHOULD be fine. However, for me I have a second battery in my vehicle that runs my fridge, and that is kept topped up by a 100w solar panel on the roof of the vehicle, so for me it's not a concern as I'd charge in the field off that fridge battery.

    I've thought quite a bit about how I'll charge in the field, as I'm planning on camping with my P2 and using it for 4wd convoy photography etc.
    My theory at the moment is to get probably 2 more batteries for a total of 5, and maybe one or two more chargers. Then just be sensible about cooling down times between flights, stopping for a cold drink myself occasionally, etc, and the periods where I'm totally without a charged battery shouldn't be too bad. I also think there would be significant gains in not going right down to 20% of battery life. I tend to land at 40% unless there's something really unusual going on. I"m paranoid about batteries dying mid flight and dropping 3 grand into the lake. So I'm tending to be overly gentle on them at present.
     
  12. p fandango

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    i've already got 4 batteries, i'm going to get 2 more mains chargers soon to (to make 3) & run them off a spare car battery & mains invertor. Anyone any ideas what wattage 3 mains chargers will draw?
     
  13. glataif

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    The absolute easiest way to fix this problem is to first:
    Buy one of these http://www.amazon.com/TOOGOO-Charger-In ... B00CAMJ76E
    Bring Phantom Charging cord along with you and charge while in the car or in between flights. It saves you a ton of $$$$$$

    Welcome :geek:
     
  14. p fandango

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    i've already got a 150w invertor, just need to see if it can cope with 3 batteries (& a 19" monitor) running at the same time
     
  15. MrC

    MrC

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    3 mains chargers will use 150w if all running on drained batteries. I would imagine a 150w inverter definitely isn't up to the job. I would be looking at a 300-500w inverter. I have a 300w inverter for one charger.