Long story short, had an RC drone with 3.7V ~1400maH lithium batteries and switched to 3.7V 2.2AH battery. But now the whole electronics cut-off when the throttle is pushed beyond mid-way (i.e. Higher currents). Otherwise it works fine at low motor rotations.

What might be a consideration that I might have missed related to battery selection?

  • 2
    \$\begingroup\$ Perhaps the batteries can't provide as much current as the originals? \$\endgroup\$
    – Hearth
    Commented Jan 28, 2019 at 3:09
  • 3
    \$\begingroup\$ What's the old and new battery discharge rates? Look for "C" numbers: like 5C or C/2. What's the figures for these two batteries? Look them up somewhere. \$\endgroup\$
    – jonk
    Commented Jan 28, 2019 at 3:57
  • \$\begingroup\$ Weight may be a factor. Extra thrust required to fly more weight = extra current = tripping. \$\endgroup\$
    – user16324
    Commented Jan 28, 2019 at 21:52
  • \$\begingroup\$ I'd agree with @jonk here, who has a similar answer to Neil_Uk . They have different C ratings and that can explain the lack of sufficient discharge. \$\endgroup\$
    – PreScalar
    Commented Jan 29, 2019 at 3:10

2 Answers 2


Lithium batteries are crudely divided into two types, 'energy' batteries and 'power' batteries.

'Energy' batteries are optimised for best energy density, at the expense of power output. They have thin electrodes to allow most of the battery to be used for energy storage chemicals. Due to the higher internal resistance, their output voltage collapses at high loads.

'Power' batteries are optimised for best power output, at the expense of energy storage. They have thick electrodes for low resistance, so less of the battery volume is available for energy storage chemicals.

Power output is often expressed as a 'C' rating. A 60C 1.4Ah battery will output far more current than a 20C 2.2Ah for instance, 84A versus 44A. Check the C ratings of the old and new batteries.

  • \$\begingroup\$ Yeah, I think you're right, that is a consideration I did not know about and thus overlooked. Thanks for that! I'd like to upvote you but I'm low juice, won't allow me to upvote... Thanks! \$\endgroup\$
    – PreScalar
    Commented Jan 29, 2019 at 3:08

Although ESR is not the best indicator of mAh capacity , the ESR is related to C charge and discharge rate and amp rises with acceleration as voltage drops with ESR*I. So if ESR causes V cutoff, your actual C rate on this battery is too low regardless of label.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.