Calibration Comparison New TB48 Batteries
3rdParty “Intelligent Discharger” vs DJI “in craft” protocol
Battery A - Brand new, used device to run down to auto shutoff (supposedly 3.5). Charged Full after resting for hour+ to insure at room temperature.
Battery B - Single previous charge depleted to about 24% from flight, used Inspire 1 craft (powered on only) to run down to auto shutoff per DJI recommendation). Charged Full after resting for hour+ to insure at room temperature.
Stored both batteries in identical ambient condition for 24 hours. Installed each in craft within minutes of each other (turned craft on only, no other operation), read GO App data for the batteries
Bat A 100% 5700/5700 25.9v 4.31-4.32 cells
Bat B 100% 5700/5700 26.0v 4.32-4.33 cells
Caution - the current through the third party device 35w bulb creates an extremely hot environment and even the procedure suggested by the supplier (“keep away from any flammable objects”) is inadequate. In my case the device was carefully isolated in an open area (at room temperature) and even so the bulb’s heat melted and charred the plastic connector where its leaders are connected to the wires (see graphic). If you are going to use this device it is imperative that you design a heat sink (like a 4” length of aluminum pipe) for the device e and a method to insure the light remains in an upright sate and cannot fall to side.
Conclusion - since smart battery logic ultimately decides when to shut down theoretically should be little difference in “end result”. That means speed of discharge (current draw) is biggest factor between options. There is no meaningful difference in end result, both batteries end up with full 5700 capacity. The only difference would be time required to discharge and dangers of 3rd party device.
Open questions is battery warranty affected by using 3rd party device, is the higher discharge amp rate for the “tail end” depletion of the 3rd party device “healthy” for the battery life compared to the slower discharge rate from the inspire simply being “on” (no motors - just logic and radio draw)?
3rd Party Amp Draw TB48 is at 26v full (@4.33v / cell) versus 21v empty (@3.5v / cell)
Mode 1 - Storage voltage - discharge from full to 23.1v (3.85/cell) is average 24.5V so @35watt (bulb) average draw is 1.43 amps
Mode 2 (click button on circuit board) - discharge used battery at 22v average so @35watt (bulb) average draw is 1.5 amps.
Recommendation - Since full discharge is an occasional routine maintenance item I would highly recommend using the DJI recommended procedure at home when you have the time, a battery can be inserted, craft turned on and left. It does not require constant personal monitoring during the entire process demanded by the dangers of the 3rd party device.
FYI - 3rd Party Device Instructions I found online, no edits (device just came in a baggie - no instructions)
As we know,lithium polymer battery used by RC aeromodelling can not be stored in full voltage, full power status should not more than a day. battery is always in full status, it is very easy to Swell, reducing the discharge Ability and battery capacity, may be directly scrapped.
Battery will automatically diacharge to lower than 3.85V pluged with discharger( lit the 35Wh lamp) when voltage is higher than Storaging voltage 3.85V, convenient and safe are not afraid to discharge too much. Greatly extend battery life!
Discharger can automatically identify the number of battery cells (3s-6s), short horn sound N times (N = number of battery cells).
Intelligent battery after booting, discharger finish reporting the number of cells, automatically to discharge, the default discharge mode is mode 1 (mode 1 discharge to saving voltage N * 3.85V, blue lights flashing slowly for 1 time), finish discharging, the bulb goes off while the speaker rang 5 times faster, indicator light is on, and you can discharge the next set of replaceable batteries. Phantom battery discharge from full power to save voltage is about 35 minutes.
During discharge process short press the button once, automatically switch to Mode 2 (Mode 2 will deeply discharge to N * 3.5V, blue lights flash 2 times), finish discharging the lamp will turn off while the horn rang 5 times quickly, can replace next set of battery. Mode 1 Mode 2 can freely switch (under voltage permitting)
