Everything you need to know about LiPo batteries

LIPO BATTERIES

Lithium-polymer batteries, also called LiPo packs, are now the only batteries used in RC Drift thanks to their compact size, light weight, and above all their high performance.

Watch our video on battery use and maintenance

WHAT DO THE NUMBERS ON A LIPO BATTERY MEAN ?

The numbers shown on LiPo batteries help you understand their characteristics. There are three markings that indicate the most important parameters of your battery.

VOLTAGE

A LiPo cell has a nominal voltage of 3.7 V (or 3.8 V in the case of HV batteries). You will often find higher values such as on the battery above : 14.8 V means that there are four cells connected in series because the voltage adds up. In the RC hobby world, you will often find 2S batteries to indicate the presence of 2 cells, 3S batteries for 3 cells, 4S batteries for 4 cells, and so on. In RC Drift, only 2S batteries are used.

Battery voltage affects the rotation speed of the electric motor, so it determines the speed of your radio-controlled vehicle. For brushless motors, power is rated in kV (RPM per volt). For example, a motor rated at 3,500 kV will spin at 3,500 rpm for each volt, so with a 2S LiPo battery it will spin at 25,900 rpm, with a 3S battery at 38,850 rpm, etc.

To help you, here is a quick summary table :

HV batteries (High Voltage)

These are the new-generation batteries that provide more power and greater capacity. You will charge your battery to 8.7 V instead of 8.4V. Ideally, you should have a charger compatible with LI-HV (LiPo High Voltage), but it is not mandatory. You just will not charge them completely, but you will not damage them.

CAPACITY

The capacity of a battery determines how long you can use it before it discharges. It is expressed in milliamp-hours (mAh). The higher the value, the greater the car's runtime  is large. In RC Drift, a 4000mAh battery with the electronics from the MST RTR kit will let you drive for around 20 minutes.

DISCHARGE RATE

The C rating is the maximum safe continuous discharge capacity of your battery. For example, on the battery above, 45C means you can discharge the battery at a power up to 45 times the battery capacity continuously, i.e. 4000 mAh 45C = 4.5A x 45 = 202.5A max continuous discharge. Going above the max continuous discharge can, at best, cause the battery to deteriorate faster and, at worst, set the battery on fire. Always choose a discharge rate well above your maximum continuous discharge because it can vary depending on the type of surface, tire size, or even the weight of the vehicle. (For MST RTR kits, 45C is more than enough)

HOW DO I TAKE CARE OF MY LIPO BATTERY ?

PRECAUTIONS TO TAKE

Lipo batteries offer power and runtime to drifters, but these advantages come with a few drawbacks. If a Lipo battery is damaged, since lithium is very reactive when in contact with water or moisture, it can release toxic gas and cause a fire. Nevertheless, this type of battery presents no danger as long as you follow certain safety instructions. (In the end, you have almost the same thing in the smartphone you are holding in your hands)

• Get rid of a lipo battery immediately if it has started to swell, is damaged, or has been punctured, by taking it to an approved hazardous waste disposal center.
• Do not try to charge a damaged battery.
• Do not leave the battery in a vehicle or directly exposed to sunlight.
• If your lipo battery catches fire, do not put it out with water, use sand or an extinguisher for electrical fires instead.

CHARGING A LIPO BATTERY

New Lipo batteries are always charged to 40% of their total capacity because for manufacturers this is the best way to store them over a long period. A first charge is therefore necessary before use. Do not use the fast charge function (Fast Charge) during the first charge cycles and do not use a battery charged below 50%. This is to preserve their lifespan and performance. In general, Lipo batteries should never be discharged below 3.2 volts per cell or they may be damaged, because below this voltage the battery chemistry has very little chance of recovering and therefore makes charging your battery impossible. In practice, set your lipo cutoff on the ESC to 3.5v/cell, which is even better. As for RTR kits, the ESC is already correctly programmed from the factory.

Before charging a Lipo battery, you must remove it from the radio-controlled vehicle and inspect it to check that it is not deformed and has no cuts. You must use a charger suitable for lipo batteries and never place it on a flammable surface (carpet, wood, etc.) or inside a vehicle with the motor running. You must also monitor the battery throughout the entire charging time. The best way to charge safely is to have a fireproof charging bag and never leave your home or any other place while a battery is charging.

Before charging a LiPo battery, you must remove it from the radio-controlled vehicle and inspect it to check that it is not deformed and has no cuts. You must use a charger suitable for LiPo batteries and never place it on a flammable surface (carpet, wood, etc.) or inside a vehicle with the motor running. You must also monitor the battery throughout the entire charging time. The best way to charge safely is to have a fireproof charging bag and never leave your home or any other place while a battery is charging.

HOW DO I SET UP MY CHARGER ?

A LiPo battery generally charges at 1C, meaning at a rate equal to its capacity. Example :

• For a LiPo battery of 4000mAh (4Ah), the charging current to set on the charger will be 4A.
• For a LiPo battery of 4500mAh (4.5Ah), the charging current will be 4.5Ah.
• For a LiPo battery of 5000mAh (5Ah), the charging current will be 5Ah.

It will take about 1 hour to charge the battery.

STORING A LIPO PACK

The ideal place to store your LiPo batteries is ventilated, cool, and dry, with a temperature between 5°C and 27°C. The batteries should be stored at half charge (around 3.8 volts per cell) : on modern chargers there is a "storage" function to reach the storage voltage. During transport, the ambient temperature must be between 5°C and 50°C and protected from sunlight. . If you are not going to drive within the following week, leaving the batteries fully charged will make them swell in 90% of cases ; conversely, leaving them fully discharged for too long will cause them to drop below 3.2V and you will be able to throw them away because it will be impossible to recharge them ( there are techniques to restart them but we will not give them to you because it is far too risky with a high risk of fire ). Store your batteries in a fireproof charging bag