BETAFPV 1S BT2.0 Battery Charger 4.2V Mod

by Combinacijus in Circuits > Remote Control

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BETAFPV 1S BT2.0 Battery Charger 4.2V Mod

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This simple reversible mod change charge voltage from 4.35V down to 4.2V, thus reducing battery wear

Supplies

  1. BT2.0 Battery Charger and Voltage Tester V2 (Link)
  2. Soldering iron
  3. Solder
  4. [Optional] Thin wire

Split the Case

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Split the case by hand or use a knife to pry open

Take Out PCB

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PCB is just tightly fitted in the plastic case an can be removed by hand

Find Voltage Set Resistors

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According to documentation voltage set resistor is connected to FB pin. To be sure you can measure resistor value with multimeter without desoldering it. It should be around 40kΩ - 50kΩ

Bridge Resistor to Make 0Ω Connection

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Max charge voltage can be changed by changing resistor value.

Manufacturer set it to 4.2V + 0.15V = 4.35V which according to the formula requires Rx = 0.15V / 3.01 / 10^(-6) = ~50kΩ resistor.

But to set it to lowest possible voltage 4.2V resistor should be aka no resistor.

This can be achieved 2 ways:

  1. Solder thin wire to both sides of the resistor to short it (recommended because it can be easily undone)
  2. Desolder resistor and bridge the pads with solder

Test

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Now it should charge to roughly 4.2V