What cell voltage should I use to charge a 2S 7.4 V LiPo battery?


My battery charger asks for a cell voltage. To charge to full, should this be set to 7.4 V or is the 7.4 V split between the two cells? If you know of any good resourses to look at on batteries that would be excellent.

Battery Changer

Here is the battery I want to charge.


Best Answer

It looks like this setting is OK.

One LiPo cell will have a (maximum) voltage of around 4.2 V.

2S means that there are 2 cells in series. In series means that the voltages add up so for a 2S battery you get 4.2 V + 4.2 V = 8.4 V.

Now things get confusing because on your battery is says 7.4 V!

When a LiPo cell is fully charged its voltage is around 4.2 V

When a LiPo cell is almost empty its voltage is around 3.7 V

What they list on batteries is the "almost empty" voltage which is around 3.7 V per cell, of which there are 2 in series so: 3.7 V + 3.7 V = 7.4 V.

Your charger also says "2S (7.4 V)" so that's OK.

The Current setting might be a bit high. I would take that down to 2 or 3 A especially if you can accept the longer charging time.

Charging / discharging cells with high currents decreases their lifetime so if you can, take it slow, use a lower current.

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