Car charging LiPo batteries

...A 5400MAH 3S pack can draw 5.4+ amps while charging. 3 could draw 16.2+ amps.

Cpt Bob, I wonder if this is accurate? My dji supplied "Power supply" is rated only 12.xv, 4amps max, so it is not even capable of providing a hour charge @ 5.4amps... My batts always take many many hours to charge the partial amount I remove per flight.

My battery seems to take well over 3 hours to charge from 60% to 100%. That is only 40% of 5.4ah.... so .4*5.4= 2.16ah charge.... so really, if this takes 3 hours, then the dji charger is putting out 2.16ah/3h= 0.72amps. Add in about 15% more for efficiency and it is still less than 1 amp to charge our smart batteries....

Not 5.4 amps.

I do not have a discharged battery here so cannot measure it, but I would be willing to bet a six pack typical charge is around 1 amp per battery. I can see no reason a typical 20 amp cig lighter outlet cannot handle upto about 20 batteries at once.
 
I have a solar panel to keep the car battery and charge the LiPos went im in the field.

I have a couple of small solar chargers (maintainers) how large is yours and what did it cost you.
 
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Any time I have actually watched how long it takes to charge my 2 bats it always been about 2 hours per battery.

I will have start doing some of my own current draw test to add to this thread.

I just purchased this adapter for $8.00 at Radio Shack and it comes with 10 amp fuse. We will give it try but I might have fly to get a dead battery. Not today since about 98 degrees here in the Pacific NorthWet.

Dry this week.
 

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You need the DJI car charger, and a 50watts solar panel, they cost around $150 park your car, plug the solar panel to the car battery and fly while the other battery charges.
 
How long have you been doing this? Noticed any issues with heat or signs of current overload when the engine is running (the voltage would be higher with alternator turning)? One last question as this seems too good to be true to me being as I currently use the invertor to run two chargers while engine is on. How long does it take you to charge the batteries?

I have seen no change at all from using the dji charger on AC. I think people need to differentiate between "Power Supply" and "Charger". A Power Supply does simply that; it supplies a voltage at a rated current. A "Charger" contains circuitry that will meter and regulate voltage and current to correctly charge the battery. The dji "Power Supply" (NOT "Charger", read the label..) puts out 12.6 volts at 4 amps. D.C. is D.C. A typical alternator puts out 13.8 volts at well over 100 amps. My Grand Cherokee alternator is rated at 135 amps. Charging these batteries is incidental. The battery packs will only draw as much current as the integrated LiPo charger will supply them with. There is no "current overload" issue. The charging times are the same, perhaps a bit shorter in the vehicle. Especially when charging multiple batteries.
 
Thanks CapnBob. I was thinking the dji p/s had limiting circuitry. So the upshot to these $120+ batteries is better charging options. I have a pair of 12 volt batteries taken out of an APC 1500 ups that I could use as power taps when out.
 
CapnBob,
All your posts make sense to me, everybody is so used to chargers. If I have 2 Dead Batteries and if they were to draw 5 amps each for 2 hours each. 20 amps total. I Shouldn't have to start the car. I will test this, this weekend.

Thanks Rod
 
I lost my P2V+ before I did any test, The P3 uses voltage is 15.2, so this idea is over on the P3. Mistake I was making was turning on the batteries before I put them on the charge. The batteries were then charging one by one the lower charged one was getting a charge off the higher charged one. The charge bar to charge up to three a once was getting to hot.
 
Why not use a solar charger rather than an automotive plugin? What level of voltage is best for charging the DJI 2+ batteries? There should be solar panels just right for charging.
 
Why not use a solar charger rather than an automotive plugin? What level of voltage is best for charging the DJI 2+ batteries? There should be solar panels just right for charging.
The battery for P2 is 11.1 Volts 5.2 Amps so any voltage above that will charge it.
The output on the power supply is 4 amps. It usually took 2 hours to charge. That means you need a solar panel that puts out 4 amps to charge a battery that you get 20 mins of fly-time. I would use a solar panel to put a charge on my vehicle when parked. I drive to fly (not camping), solar panels are hard to keep pointed at the sun when traveling.:)
 
just keep in mind that any voltage over EXACTLY12.6vdc will exceed the dji p2 smart battery maximum charge rate.of 1C and will signifcantly lower your battery cycle life.

There is NO (zero) current control on the smart battery; it relies on the dji dumb power supply rated 12.6v max output rated 4 amps; when charging, the actual voltage droops to 11v or so and thus limits the current to 4 amps - until it reaches the magic 12.6v max level and current begins to drop and then smart batt shuts off.

use 14.4v from your running car and you will be charging with near 10 amps and will harm your battery. Leave it on that voltage and you will not charge it to CC-CV proper max level.

best to stick with the dji power supply - use an inverter in your car if you must. Or use a good lipo performance charger and extend your batt life yet more as some of us do.
 
It seem to work through the 12 volt on the car with this item.
Battery Parallel Charger Charging Board Plate for DJI PHANTOM2 Vision Quadcopter | eBay
But I didn't get really get test it. Time voltages and amps.

I did test the last 2 days having three P3S 3 batteries on the factory power supply, on normal power and with a Triplite inverter in a 07 Yukon.

With out the engine running you open the doors and the inverter starts its low power squeal, start the engine and it shuts off. So every time you start the engine you have cycle the inverter. Third battery in the Yukon, its always done this. What a pain, guess I should get another inverter.
 
It seem to work through the 12 volt on the car with this item.
Battery Parallel Charger Charging Board Plate for DJI PHANTOM2 Vision Quadcopter | eBay
But I didn't get really get test it. Time voltages and amps.

These paralleling units are fine - IF you use the dji power supply and NOT the car 12v system - IF you want batteries that last a fair amount of time.

If you don't need your batteries to last over about 20 charge cycles, then charging directly from the car battery is fine.
 

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