So mAh isn ' t quite power over time , it ' s really just the integration of current over time . If you could measure the current the gimbal consumes , and integrate that value over time then you could know a running total of mAh consumed from the battery . However it doesn ' t appear you have a current sensor in that setup , or anywhere to display that info , so the easiest way to tell the rough state of the battery is by its voltage . Fully charged it will be at 4 . 2 V per cell . As it discharges , that pretty quickly falls off to somewhere around 3 . 8 vcell and then slowly declines as the battery discharges until it falls to close to 3 . 5 Vcell or so . After that point it will begin falling off rapidly , and to avoid damage to the battery it should not be allowed to fall below 3 . 0 V per cell . Each battery will have a different t discharge curve describing the voltage at a particular charge state . These will also be different for the same battery under different loads . The simplest thing is to simply watch the voltage and turn the gimbal off and charge the battery when it hits 3 . 5 Vcell . You can estimate about how long a battery will last based is the current draw 350 mA in this case and the capacity in mAh . Simply divide the number of mAh by the current draw in mA to determine roughly how long you can expect that battery to last . So for example if you powered it with a 2200 mAh pack , then it would last 2200 mAh 350 mA 6 . 28 hours . In reality the current draw isn ' t constant at 350 mA and will vary according to how much the gimbal has to move , among other factors . So this is not likely to be extremely accurate but is a good ballpark number that you can expect to change depending on use case . If you want an accurate estimation of the state of charge of the battery and how much time you have remaining , that is a surprisingly difficult thing to do . If you just want a rough idea of when you need to change batteries , and about where it is on the discharge curve , then the voltage checker is the simplest solution .