FT-817 battery holder with BMS

Parts:

Metal AAA Batteries Spring Contact Plate Terminal https://www.aliexpress.com/item/4000092167957.html?spm=a2g0s.9042311.0.0.343f33edrXt5X5

BMS 3S 10A 12V Lithium Battery Charger Protection Board Module for 3pcs 18650 Li-ion Battery Cell Charging BMS https://www.aliexpress.com/item/32900372190.html?spm=a2g0s.9042311.0.0.264d4c4ddPbHZM

Attention: bms starts up when you first install or replace batteries by supplying external power to the board through the radio power connector. Or, in another case, by short-circuiting the B + and P + pins of the BMS board.

Instruction:

Installation is carried out by pre-soldering the wires. For this, the mounting tab of the metal plate is bent in the opposite direction, after which a wire is soldered to it. Then the plates are inserted into the slots and soldered to the BMS board, which then sits in place.

So far, it is known for sure that the battery is automatically turned on / off when an external source is connected. In theory, charging is possible with small circuit changes. Two transistors in the circuit have 2SB1182F5/Q Ik max = 2A, diode RB051L ~ 3A. My li-ion charger is 0.7A, so the radio circuit can be modified. It is not difficult to tune the circuit to provide more charging current. The charging current, which is set by the manufacturer to about 180 mA, can be easily increased. Resistor R1435 with a resistance of 4.7 ohms determines the battery charge current.

Adding:

You can simply put a jumper in the circuit so that power always comes to bms.