Was perusing HK this morning and saw this... Has anyone tried it yet?
http://www.hobbyking.com/hobbyking/..._for_DJI_Phantom_2_Battery_AR_Warehouse_.html
http://www.hobbyking.com/hobbyking/..._for_DJI_Phantom_2_Battery_AR_Warehouse_.html
some more info to help understand our p2 smart battery charging...
each cell is absolute max voltage 4.2v, so all '3' make 12.6vdc. When thebatt gets used, this 4.2v goes down until it is around 3.6 or 3.7v minimum (no load - less under load while flying).
Charge for lipos, including ours, is meant to be CC-CV (constant current then constant voltage at very end).The smart batt has no control other than counting the coloumbs going in and coming out for tracking purposes, and a big on/off switch to the outside world.
Their internal resistance is low at about .030 ohms, but each is actually 2 in parallel, so each set is about .015ohms, and so 3 of em in series is about .05ohms. When charging, we have to put a very small amount more than terminal voltage across them to force current into that resistance.
The current stays pretty constant while the batt charges; if you ever measured it, you would see for a 2 hour charge, about 1.9 hours is at constant 4amp, then the last few minutes, as it approachs it 4.2v per cell (12.6v total), the current drops off. Conceivably if you kept exactly 12.6 v across it, the current would go to zero and remain there, not overcharging. The smart batt watchs this current reduction and shuts off the charge at 0.1amp.
But the lipo has a weird personality: you can leave 12.6 on it forever and current remains low, but go a few millivolts OVER than and the current again goes up thru the roof as explained in my previous post. Since our smart batts seem to shut of as fully charged when current reaches 100ma, I suspect that if left on a car charger at any voltage above 12.6 it will continue to pull that high current and never shut off. It should have to overheat and catch fire shortly thereafter. It MAY be that the smart batt just goes to 12.6v then sits there for a given timer amount of time and then pulls the plug, but that has not been my experience yet. I would not want to be one to test that either.
My multi-charger also charges PB batteries and that setting is how I charge my Phantom batteries. Of course, use the 12v setting.
Yorlick's and other comments made me reread what had posted. In no way am I proposing this method as a primary charging solution. You will kill your batteries in short order if you use an unregulated current method. I have used this successfully in the field as a way to extend flying time in those times when three batteries are done before I am. I always have a voltmeter in parallel, and I watch them closely. In the field, I don't want to wait 2+ hours for a "proper" charge, so this works for me short-term. I am sorry if I was not clear in what I was trying to say.
Danny, why not use your lipo setting? That is how I charge now most of the time. That way I can document the exact mah put in, add it to the mah dji reports before the charge (after last flight), and verify that dji then reports the correct mah in assistant! I find I put in about 3% more than dji reports, which seems good to me - gotta charge a tad more mah than removed to fully charge - the small amount extra goes to heat. Verifies everything this way.
This is the one I have. Works great for r/c: https://www.batterystuff.com/solar-chargers/t-01003.htmlI have never used a VOM or Multimeter to measure current. I never understood why they even make that an option. I had a clamp-on current probe that read out my fluke, but it broke awhile ago. I'm looking for a replacement. Maybe an Extech MA120.
nice one. mine is similar and cheapo, but I have checked it against our good flukes and it reads close enough for me. mine also has a 20amp scale which helps on resolution, altho if yours stays accurate down to 1-4amps on 200amp scale, great! In case you did not know, if you wrap the wire around the jaws 1x, it cuts the 200amp scale to 100amp, 2wraps makes it 50a, 3 wraps, etc. so if you make up a #12 or so feed wire to wrap around, if you leave it long enough to wrap 1-4 times, you can increase your resolution and accuracy then by that factor.