Skip to main content

How to Charge RC Lipo Battery Safely?


There are many charger options available on the market, ranging from AC wall devices to high-current multiple-output chargers, all equipped with built-in balance ports. However, it is worth noting that many of the cheapest chargers on the market only include a single balance port. These chargers are typically meant for charging toy quadcopters and are designed to charge the batteries individually. If you have some experience, it is recommended to opt for a more advanced charger. Of course, whether you are using an advanced charger or a regular charger, they almost always have the same electronic interface.

Charging Process

Firstly, you must use a LiPo charger to charge LiPo batteries. However, most LiPo battery chargers can charge many different types of batteries. If using one, make absolutely sure not to charge LiPo batteries in non-LiPo mode. This can lead to malfunctions and fires.

Charging LiPo batteries is different from almost all other batteries on the market. It involves applying a constant voltage slightly higher than the current battery level to the battery terminals. Current flows through the battery, initiating the charging process. The charger must regulate this current to avoid over-saturating the battery. Once the battery reaches the set voltage, the current will slow down and eventually stop. LiPo batteries do not have a safe saturation point like, for example, car batteries, where they will no longer accept a charge. Overcharging them can lead to anything from simply rendering the battery useless to causing safety hazards. Additionally, do not insert LiPo batteries into car battery chargers or NiMH or NiCd chargers, as they can explode.

Typically, chargers have a range of modes available: charge, fast charge, and balance charge. It is recommended to use the balance charge mode.

Pay attention to ensure that you select the correct cell count! Although most chargers will issue a warning before attempting to charge mismatched batteries, they also have some built-in safety checks. These include:

  • A confirmation screen before starting charging that asks you to confirm the number of batteries.
  • Automatic cancellation of charging if no battery is detected (during balance charging).
  • Automatic cancellation of charging if the battery voltage exceeds specifications (during balance charging).

From the above, it can be seen that you can obtain maximum built-in protection when charging in balance mode. Therefore, it is recommended to charge the battery in balance mode whenever possible, unless you have received professional guidance. Do not take risks by using other modes. So, how can you determine if the battery is in balance charging mode?

On most chargers, when the screen displays “BALANCE,” you can only charge the remaining capacity. If you see “CHARGE,” it means you are in “normal” charging mode, and even if you plug in the power, the battery’s balanced capacity will be ignored. The Ah rating of the battery will help you determine the charging current. Typically, charge the battery at a rate of 1C or a value equal to the battery’s mAh rating. For example, if you have a 1.3 Ah battery pack, charging it at 1.3 Amps is considered 1C charging. Some batteries have a rated charging speed that is faster (2C or even faster), but faster charging speeds may generally shorten the battery life.

Charging Safety

  • When charging lithium batteries, keep away from flammable materials. You can charge them in a metal box or place a bag of sand on top of the charging box to prevent the batteries from catching fire. The fire will burn a hole in the bag, and the sand will smother the flames.
  • As long as your battery is not physically damaged and remains balanced, you can safely charge it. The most important precaution you can take is to never charge unattended batteries. You must be able to react quickly if anything happens.
  • Before charging, inspect each cell of the battery to ensure it remains balanced with the rest of the pack. You also need to check for any swelling or damage. If so, it’s best not to charge the battery and replace it with a new one.
  • Do not leave the battery unattended during the charging process. If you are charging the battery indoors, the first line of defense is to place it in an area where it can be observed, which is particularly important. Regardless of the location, make sure the room where charging takes place has a fire alarm.
  • How do you know if something is wrong? Overcharged or damaged LiPo batteries will start bulging and emit a distinct odor. If you notice this, immediately remove the battery and dispose of it outdoors where it does not pose a danger. It should be placed in a safe location for several hours before being soaked in a saltwater solution for disposal.
  • Battery Box

It is a reasonable practice to place the battery in a fireproof container during the charging process to prevent or reduce damage in case of accidents. Whichever container you decide to use, make sure not to seal the battery inside an airtight container. LiPo batteries release pressure and heat, and if sealed, it could be enough to create a bomb.

  • LiPo Bag

Some manufacturers have introduced explosion-proof bags specifically designed for charging batteries, which is also worth considering.

To ensure the safety of charging, it is necessary to develop good charging habits:

  1. Make sure the charger is set to “LiPo” mode.
  2. Verify that the battery charging rate is correct. To do so, divide the mAh value of the battery by 1000. For example, a 1300mAh battery pack should be charged at 1.3A.
  3. Double-check the series mode and reset the count after starting the charging process.
  4. Confirm that the charger is set to the appropriate unit count mode (e.g., 3S, 4S, etc.).
  5. Cross-check the number of batteries by physically inspecting the battery or the balance connector.

Leave a Reply

Close Menu

About Salient

Wow look at this!

This is an optional, highly
customizable off canvas area.

Product Enquiry