Batteries , Li-ion vs Li-Po Which better? why?

Hi all ,

Most rc fliers use Li-po batteries , But when I use it I just get fly about 10 min then battery off and need throttle again - seems to became hot -

When I use Li-ion batteries I can fly about 50 min but I get many problems :

  • PMU does not measure voltages and power accurately
  • The motor thrust is much less than li-po battery power
  • Couldn’t use Battery failsafe coz voltage become low when full throttle .

I am using Li-on battery from Panasonic NCR 18650B 3.7 v 3400 mah (6cell*5p)

Can you help me in how to get long time battery , best motor thrust ?

BATTERY : LI-ION 24.6V , 17A


You haven’t said what your current draw is?
Plane or copter?
LiPo size that was getting hot?
Sounds like your current draw is too high

1 Like

@mboland ,

on li-ion battery
Power is always variable depending on throttle out pwm
When full throttel . The current value between 30 A and 37 A and this is on TAKEOFF
When Cruise current value to be between 13 A and 20 A PWM about 1600

plane not copter.

Li-po is 25.2 V , 17000 A

I am confuse Li-ion give me long time but with no accurate measurement

If the LiPo is getting hot it must be only a 10C rated, and how did you come by the current measurements?
Have you verified the battery monitors current measurements with a meter?
What have you set the ESC voltage cutoff value to?
In setting up our competition drone we aimed at 1hr flying time with 15Ah of LiPo on board.
9.5kg takeoff and we only got 30min, changed the prop and we got 65min.
Takeoff current was 57Amps but cruise was only 12Amps.

It sounds like you need to do a lot more measuring and tuning.
Flight trimming the plane would also yield benefits, and drag reduction.

Inherent in LiIon batteries is the voltage drop.
Draw a lot of amps and it really sags, which is why they are not that successful in multi rotors.


That’s great information you are right , I need to do more measuring and tuning

I got the current measurements using UNIT UNI-T Digital Clamp Meter

  • No idea about ESC voltage cutoff value , I am using Dualsky 80 A ESC with it’s default setting , What it should be ?

Dose there any method to measure the required Battery to fly my plane for 1 hour ?

My plane is 4.6 kg .

Using your figures, to cruise for an hour you are going to need between 15Ah and 22Ah battery.
If you are needing 20A to cruise a 4.7kg plane then you some serious inefficiencies you need to address.
We can cruise a 9.5kg plane on 12A to 15A at around 45kph.
This was an off-the-shelf ARF model.

You will need to look into the programming instructions for your ESC to see where the cutoff is set by default.
If running LiIon I would disable it altogether.