How to use BC-4S15D / 2s/3s/4s LiPo battery charger/checker

Introducing how to use BC-4S15D, a small palm-sized charger that can be used to charge batteries for various radio-controlled models such as FPV drones / Tiny whoops and electric model guns. For the basic knowledge of LiPo battery, see Drone Battery Knowledge / How to long-lasting and reviving . Also, for more information on micro drones, see Introduction to FPV drone for beginner / How to fly Racing drone .

Drone Battery Knowledge / How to long-lasting and reviving

Introduction to FPV drone for beginner / How to fly Racing drone

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Table of contents

What is BC-4S15D
Batteries supported by BC-4S15D
Introducing BC-4S15D
Use as a voltage checker
Charge the battery

KNACRO BC-4S15D Battery Lithium Lipo Balance Charger With Voltage Display 1500mA

KNACRO 2017-08 USD23.50

Ready to charge, one step to finish charge process; ready to display, display the voltage at any time. High charge accuracy, ±10mV(max); Multi-protection, keep charging safe. Auto recover the over charging battery, save energy, balance process don't need discharge. Operating Voltage Range: 9V-16V DC; Operating Temperature: -20-45℃; Cells Type Supported: 2-4 cells Li-lon/Li-poly; Input Power Request: Recommended 30W. Max Charge Power: 25W; Charge Current: 1500mA; Charge Accuracy:±10mV; Balance Current: 1000mA; Display Accuracy: ±10mV.

(US) (UK)
MINGCHUAN Battery Balance Charger, Lipo Battery Charger, BC-4S15D

MINGCHUAN USD20.39

Excellent circuit design: Large range of charge currents Store function, allows safe storage current. Practical for variety of batteries: Suitable for charging LiPo, LiFe, NiMH and NiCd batteries. Multi-Function: Designed with fast charging and storage modes for Li-Po. Maximum Safety: Low Input Voltage setting,Capacity limit, Processing Time limit,Temperature Threshold,Delta-Peak Sensitivity.

(US) (UK)

What is BC-4S15D

BC-4S15D is a very simple charger that can charge and check the voltage of 2s/3s/4s LiPo batteries.
Originally a Chinese product, similar products are available from multiple vendors. In addition, two types of 1.5A version and 3.0A version are sold depending on the charging current. The 3.0A version charges faster, but there is a risk of explosion or fire depending on the C value of the connected battery. Especially for beginners, we recommend the 1.5A version, which is easy to use.

Batteries supported by BC-4S15D

The following types of batteries can be charged.

Supported battery types
types	Number of cells / voltage
LiPo (Lithium polymer)	2-4 cells

Please note that LiFe (lithium ferrite), LiHV (lithium high voltage polymer), NiMH (nickel metal hydride), NiCd (nickel cadmium), etc. are not supported.

Introducing BC-4S15D

It comes in a box like this. Size comparison with iPhone.

This photo is a list of contents. Really simple. Only the charger and AC adapter are included in the package. There are no manuals or other documentation.

Compared the size of the charger with iPhone. It's about half the size of an iPhone.

The photo on the right side of the charger.
Three JST-XH type connectors for balance charging are lined up. They are for 2s, 3s and 4s respectively. However, only one battery can be charged at a time.

The left side.
A connector for connecting an AC adapter.

This is the back side photo. Specifications are written. As a charger, the accuracy per cell is plus or minus 10mV, and as a voltage checker, the accuracy is 0.1V.

Specifications for the included AC adapter. Input is AC100~240V, maximum 0.8A. Output is DC12.0V, maximum 3.0A.

Use as a voltage checker

To use it as a voltage checker, connect only the battery and charger without connecting the AC adapter. The screen will then display "ALL" followed by the total voltage. After that, "b-1" is displayed, followed by the voltage of cell 1, "b-2" is displayed, followed by the voltage of cell 2, and so on.

Charge the battery

First, connect the AC adapter and charger. The screen of the charger will look like this.

Then connect the battery to the charger. The cable to be connected is only one JST-XH type cable for balance charging. Charging will begin immediately.
During charging, the screen will display "ALL" followed by the current total voltage. Then "b-1" is displayed, followed by the current cell 1 voltage, "b-2" is displayed, followed by the current cell 2 voltage, and so on.
Each voltage increases gradually.

Charging ends when the voltage of each cell reaches 4.20V. You can remove the battery.
The product description says, "When the battery is fully charged, it will automatically stop, display 'FUL' and sound an alarm. ", but it seems that it often does not stop automatically.

When the charger successfully senses that the battery is fully charged, or when you connect a battery that is already fully charged, it will display "FUL" like this, and beep.