LiPo 2S with 3 wires, Red/White/Black

Batteries and Chargers Rechargeable Batteries
1

Hello,

I’m not sure what to make of this LiPo battery.

It has 2 cells, each 1800mAh

The issue is that it has a 3 wire connector where Red is the first wire, white is the 2nd (middle) wire and black is the 3rd wire and……
The voltage between the Red wire and the middle white wire is 3.9v
The voltage between the Red wire and the black wire is also 3.9v
There is no reading between the Black and white wire

I expected the voltage between the Red and Black wire to be the two cells in series and 7.8v…but it’s not.

Seems to be a 2 cell Lipo with the cells in PARALLEL instead of in Series.

And if that’s the case, the device being powered is receiving +volts from the Red AND the white wire?

The device btw is an Insignia Bluetooth stereo speaker.
Charging Voltage is Bluetooth level (5v)…(which tells us this is not two LiPo cells in Series.)

How would the wiring look on this? Let’s say I wanted to build my own pack from two 3.7v LiPo cells.
How would this wiring be done to have to 3 wires with voltages as outlined above?

2

May be the white wire is the terminal of the temperature sensor.

3

If that was the case, should it have 3.9v on it ?

4

You could have a shorted out cell, such as between the black and white wire. The voltage will read 0 but it will pass current. This is the lowest cell in that pack, the upper cell is reading normal.

i have found this to happen in tool packs such as Kobalt.

5

Is the White wire the Negative on both of your readings — that would make more sense for charging — the 5v charging is a typical USB type charge with a step down charging circuit — A picture is worth a thousand words :smiley: