Battery Landing Voltages vs Votlage Test readings

[kayakmtb]

Hello All

I am new to the LiPo battery and the Typhoon H, so your wisdom would be gratfully recieved.

After looking a wide range of threads, I generally aim to land my UAS at 14.7v (displayed on the ST16). With the exception of a low battery test. At present I am getting about 15mins flight time (still air).

As soon as the UAS is on the deck the voltage usually goes back up to 15 - 15.1 v. I resist the temptation to get airborne again even if after takeoff I then have 14.9 v displayed on the ST16. Mainly because I am paranoid about trashing an expensive battery or a low power induced flyaway.

I now check the voltages prior to charging and I am finding that after a 14.7v landing, the batteries read aproximately 15.3v.

So my questions are:

1. Why does the voltage displayed on the ST16 go up on landing?​
2. If the voltmeter reading is 15.3 v, am I being too conservative with my batteries?​
3. Which is most likely correct - the voltmeter or the ST16?​

Thanks all...

 

[Tuna]

When the Typhoon is flying, it's pulling a high current and the battery chemistry has to work hard to deliver that - the volts drop as it does so.

As soon as you land, and the Typhoon stops pulling that high current, the chemistry can 'catch up' and the volts rise a little.

 

[PatR]

Add heat to the equation. When the battery is working as a power source the transfer of current generates heat, which is reflected in the voltage drop. When the battery ceases to provide higher current the heat is reduced, and further reduces as the battery cools, elevating the voltage level. To be safe, consider the battery voltage when it is under load to be the true indicator of voltage state. Testing RC flight batteries under a 1 to 2 amp load has been a common means of establishing charge state for decades. It still works.

Keep doing it the way you are doing it. You're doing in right.