BG-8S is a multifunctional measuring device for testing the condition of battery packs of most model types — Li-Po, Li-ion, LiFe, LiHV, NiCd and NiMH. In addition to voltage measurement, it can perform autonomous balancing, measure servo signal parameters at the receiver output, and also function as an intelligent USB charger powered by the connected battery.
The tester measures 2-8S lithium batteries without any additional power supply, drawing energy from the battery being tested. It displays total battery voltage, individual cell voltage, and the difference between the cell with the highest and lowest voltage, which is the fastest way to identify an unbalanced battery. Batteries with a JST-XH service connector are connected directly, others via a suitable adapter. For NiCd and NiMH packs, it measures total voltage for 4-10 cells, also without an additional power source. To test 1S lithium packs and NiCd/NiMH packs with fewer than four cells, a power battery with a voltage higher than 5 V must be connected to the XT60i input socket.
In balancer mode, the BG-8S operates autonomously with 2-8S lithium batteries — it discharges the cells to the level of the cell with the lowest voltage and thus equalizes the voltage of all cells to the same value. During balancing, the device is powered directly from the battery being discharged.
As a servo signal tester, the device is connected to the relevant output (channel) or to the receiver's S.BUS socket using a three-wire servo cable in standard wiring, with the negative wire connected to the (-) contact of the tester socket. For PWM signals for standard servos, it measures and displays the receiver supply voltage, repetition frequency, and pulse width, which it also shows as the relative deflection size in percent. For serial S.BUS, it displays relative deflection size in percent and as a bar graph, for up to 18 channels. If the receiver supply voltage is lower than 5.0 V, an external power source with a voltage of at least 5 V must be connected to the XT60i socket.
The last function is a USB charger, or field power bank powered by the battery connected to the XT60i socket — which is protected by the tester against excessive discharge. It charges common devices with 5 V / 2 A and also supports intelligent fast charging Qualcomm Quick Charge 2.0/3.0, is compatible with BC1.2 and Apple devices. The maximum charging voltage is 12 V / 2 A.