Use 4s instead for 3s for 3s rated motors

Hi there!
My quad (2000g), 980kv A2212 Emax motors (880g thrust max) is making a voltage drop 1.5V during flight, making it difficult to fly even at half battery (when true 11.8V remaining)

Can i use 4s Battery for the same motors to compensate ?
*(motor pack reads Battery :2s,3s).

Saying because the voltage on 3s battery drops 1.5 during flight. May be 4s can compensate.


Hi - questions: How do you know the actual battery voltage when flying, and how do you measure the 1.5V drop? Telemetry? See below.

Are you sure the battery monitor is accurate? It may require calibration with a calibrated power supply, or a handheld meter, or a LiPo cell monitor attached to the balance leads… GL!

Why don’t you post a link to a .bin flight log because the data you are providing is not clear. What size props? It’s likely underpowered/overweight.

Let’s say you are using 1047 props on that 2000g craft. If so it’s woefully underpowered with a predicted hover throttle of 74%. On 4S, assuming you don’t smoke the Motors and/or ESC’s, it’s still overweight if it results in the same take-off-weight.

Generally you need to downsize the propellers if your stepping up the voltage. So if your on 10 inch propellers you should look at 9inch propellers on 4s.

10" props with the kit he has described would be underpowered on 4S let alone 9". It’s way too heavy for 2212-980kV motors on 3S or 4S. That’s a kit of parts for a typical 450 size craft which by definition from that Motor spec table couldn’t have a TOW of more than ~1400g. And that table is probably wishful thinking. The bottom line is a 3S 5000mah battery is way to heavy for that craft and even a 4S battery would have to be less weight than that 3S battery for proper thrust/weight.

hmm… thanks for the assessment.

Can you suggest which motors should i use ? (for my ~2,000g) setup ~550mm. (3S or 4S option available).

The options i consider for now are EMAX xt2216 1150kv == ~1350g thrust/ motor

and second is GART ML2312 motor.

Purchase a license for eCalc (it’s cheap) and you can easily determine this by running various options. But the most important design guideline you need to follow is to have a minimum of a 2:1 thrust/weight ratio preferably a bit higher… So, thrust at 50% throttle=Take-off weight at a minimum. With a 550 size craft at 2000g you will find your options narrowing. Build for 6S, that’s what I have done before on similar size craft at less weight than that. But if you have one of those crappy F450/550 frames they are not well suited to that weight.

If you want to read one of the more ridiculous threads on the forum in this regard try this:
Free Lunch

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