Decided to see if it was possible to use 3 x 18650 batteries in a AR Drone 2.0.
So I made up a 3s pack using Panasonic 3400mah NCR18650B, these are rated for around a amp draw of around 6.7 amps constant.
I thought they may be borderline on the AR Drone as I recall there is a video around on youtube of a guy doing a test and that was showing the drone pulled about 7 amps on take off and so with the weight of the rc mod and flight recorder I did wonder about whether this would work.
3 of these weighed around 137 grams.
You have to be careful where you buy these as there are many fakes around!!
Quickly made up a balance lead to charge the batteries and from new the resting voltage was 3.66 volts per cell.
As I did not have a spot welder about to contact the batts together, I just roughed up the ends so solder would take and then quickly soldered them together. If you do it this way you have to use a good soldering iron and be quick or you going to cook batteries and that can lead to possible problems and even fire, so be very careful!!
From the resting volts of 3.66 per cell and doing a gentle charge at 100mah these batteries took 803 mins and 1337 mah to a full charge of 4.20 per cell.
Again I always charge new lipos gentle at first and this is just personal choice, no scientific reason really.
So popped them into the ar drone and see how they worked or did not work as the case may be.
First thing I noticed when I took off is battery went from around 98% left on the freeflight app to just under 50% almost straight away and I thought this does not look too promising.
Carried on the flight and landed the craft at 10% left after 6 mins 57 seconds.
Well it did fly, but I could already see the amp draw of the drone was too much for these batts.
Voltage at end of flight was around 3.88 per cell when read back.
So charged them back up and the pack only took 717mah back to a full charge of 4.20 volts per cell and so was obvious these batts cant handle the high drain needed
went for another try and this time I would I would land when the ar drone auto lands at 0% battery.
This is what I see and that was a flight time of 8 mins 10 seconds and the drone auto landed at 0% left. The batts reading at end of flight was 3.78 per cell and used a total of 843mah.
So although it did fly , these batteries did not fit the bill.
I did 1 final test without the Parrot GPS Flight recorder and got 9 mins 23 seconds……
I would not class this as a fail as the batteries were able to power the flight, and I am still impressed that 18650 batteries are getting close to being able to power a quadcopter and if you put 6 of these batteries in a 3s config and not too heavy quad will get better results.
But of course you cant do that on a ar drone due to weight and also space and tiny motors etc.
So moving on , my next test will be with some Samsung 25R INR18650-25R 2500mAh and expect better results.