LiPo 2S Battery 101: All About LiPo 2S Batteries

Lithium Polymer batteries, also known as LiPo or Lipo batteries are a special type of rechargeable lithium batteries that feature electrolytes in the form of polymer gel, and in their basic form, they are soft to touch.

LiPo 2S batteries feature two LiPo batteries connected in series in order to provide larger voltage, commonly 7.4V. As such, they are commonly used as sources of strong currents in various applications, including RC cars, RC boats, RC trucks, and other toys, but also applications like robotics and similar.

Published: March 9, 2022.

LiPo 2S Batteries Features and Specifications

LiPo 2S batteries consist of two (2) lithium polymer cells connected in series (hence the "S") in the so-called 2S1P configuration.

Most of the LiPo cells used to create LiPo 2S batteries feature a nominal voltage of 3.7 volts, a maximum charging voltage of 4.2 volts, and a minimum voltage of 3.2 volts.

2S LiPo Battery Voltage

Thus, LiPo 2S batteries usually feature:

- 2S battery nominal voltage: 7.4V,

- 2S battery maximum charging voltage: 8.4V,

- 2S battery minimum discharge voltage: 6.4V.

Again, these are the most common values - it is important to check the specs of each battery model before use.

2S LiPo Battery Capacity

2S LiPo battery capacities vary from a few hundred mAh to large 10+ Ah batteries used in most energy-hungry toys, RC vehicles, and applications.

Output currents usually vary between 25 and 100C, although there are some models that are able to provide even stronger burst currents, although for a very short time.

On the other hand, 2S LiPo batteries should be charged with 0.5-1.0C currents - when compared with the discharge currents, charge currents are relatively low, but when compared with older types of batteries, 2S LiPo batteries can be recharged rather quickly.

When charging the LiPo batteries, it is highly recommended to use balance LiPo chargers that charge and monitor each cell individually.

This is very important for 2S batteries, but even more important for LiPo batteries with more cells connected in series - LiPo batteries are sensitive to overcharging and if the end voltage is 8.4V for a battery pack, it is very desirable that both cells are at 4.2V.

On the other hand, charging one cell to 4.0V and another to 4.4V (just an example), can lead to battery overheating or even bursting into flames...

That is why LiPo batteries are never left unattended when being charged, even if they are charged using balance chargers - better safe than sorry.

2S LiPo Battery Connectors

2S LiPo batteries come with two sets of cables, including:

- discharging cables feature thick wires in order to keep the energy losses as low as possible. Also, they very often feature Dean T connectors, which are almost standard for 2S LiPo batteries intended for low to moderate currents.

- charging cables are much thinner than discharging cables and they usually feature JST-XH or some very similar plug. Such plugs allow the charger to monitor, balance, charge and even discharge each cell individually.

Note: In the case of ordering/receiving the battery (or batteries) with wrong plugs, there are many adapters on the market that allow the user to connect the battery with "wrong" plugs into the device/charger that has different connectors.

Of course, each connection adds some resistance, slightly increasing the energy losses, and should be avoided if possible.

Storing and Transporting 2S LiPo Batteries

Due to LiPo batteries' great sensitivity to overcharging and over-discharging conditions, they have a tendency to overheat or even burst into flames or to explode if pushed over their limits.

In order to avoid such events and to use them as safely as possible, when the new battery (or batteries) arrives, be sure to read its instructions, especially charging, storage, and safety issues/procedures.

When charging, storing, and transporting all LiPo batteries, not just 2S LiPo batteries, it is highly recommended to use fireproof bags.

Of course, such fireproof bags are not absolutely required, but better safe than sorry.

2S LiPo Batteries Charging/Discharging Cycles

2S LiPo batteries support several hundred charging/discharging cycles, but this depends on the battery quality, discharge currents, charging currents, cell balancing, quality of battery charger, use and storage temperature, and similar.

Also, although not emphasized by many brands, when the new battery arrives, it is a good practice to make a few test charging/discharging cycles, with a gradual increase in Depth of Discharge. For example:

- charge the battery to 100% and discharge it slowly to 25% DoD,

- charge the battery to 100% and discharge it slowly to 50% DoD,

- charge the battery to 100% and discharge it slowly to 75% DoD,

- charge the battery to 100% and discharge it slowly to 90-95% DoD.

After each charging and discharging be sure to let the battery cool down.

Personally, there is no need to push the battery down to 100% DoD right away.

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Long Story Short: 2S LiPo batteries are a very popular battery type and are used from small RC toys to larger RC trucks and other applications.

When looking for a new 2S LiPo battery, always check actual dimensions, capacity, current rate, and connectors and choose according to your own personal needs and requirements.

And whatever You do, stay safe - it is, after all, your own responsibility.