How to Activate Over-Discharged Lithium Batteries?

  Many people have developed a bad habit of leaving their electric bike batteries on the bike when they are away, without turning off the air switch, and not riding for several months. When they come back to ride after several months, they find the bike has no power, and the battery cannot be charged. Even if they plug in the charger for 24 hours, the indicator light remains green. This is because the battery voltage is too low, and if the voltage difference between the battery and the charger output is too large, the charger cannot deliver the charge to the battery.

  This situation is commonly referred to as the battery being "over-discharged." The voltage of such batteries is generally only around 5.6V, not exceeding 6V. For these batteries, most people opt to replace them. However, replacing a set of batteries can be expensive, especially for batteries that have just gone out of warranty.

  Here are five effective methods that can rescue most batteries suffering from "over-discharge." It's important to note that these methods are not guaranteed to be 100% effective.

  1. Series Connection Method: Connect an additional 12V battery with a normal voltage to the entire battery pack. For example, if the original bike battery is 48V-20AH, connect an additional 12V-20AH battery. A fully charged 12V battery has a voltage of about 13V, and connecting it in series can boost the overall battery voltage. Then, use the original charger to charge the batteries. When the charger shows a red light, indicating charging, the charge is going in. Once the charger turns green, remove the additionally connected battery, and then proceed with normal charging.

  2. Parallel Connection Method: This method is slightly more complicated. For instance, if the original vehicle has a 48V-20AH battery, connect an additional set of 48V-20AH batteries in parallel. In a parallel circuit, the voltage is equal across all points, and the higher voltage flows into the lower voltage. This method is often used by battery dealers to revive completely discharged batteries. Charging can be initiated and accomplished using this method. The principle is similar to connecting a single battery to boost the overall voltage.

  3. Low Voltage Charging Method: Use a smaller-sized charger for charging. For example, if the battery is a 60V-20AH pack, use a 48V-20AH charger for charging. In most cases, this approach can successfully charge the battery. The principle is similar to the first method, bringing the charging voltage closer to the battery's terminal voltage.

  4. Single Cell Charging Method: Charge individual battery cells using a 12V motorcycle charger. This method can activate the battery, but the charging process is slow, typically taking over 7 hours for the battery voltage to slowly rise to around 12V. Charging all individual cells can be time-consuming.

  5. Special Charger Method: Some chargers automatically recognize battery voltage. Regardless of how low the voltage is in a battery pack, these chargers can identify it and charge it. For instance, if the original bike battery is 60V-20AH, and it has dropped to 30V, such a charger can still charge it. As the voltage increases, the charger adapts to higher voltage levels and continues charging. Chargers from brands like Tianeng have this automatic voltage recognition feature and are compatible with bikes like Tailg, Greenjia, and Jinpeng tricycles.

  Additionally, let's briefly explain how to activate "over-discharged" lithium batteries. The activation of laptop or phone batteries is referred to as "Power Gauge Calibration" in Lenovo Power Manager software. When using Everest software on a PC to check the power, there are "Design Capacity" and "Full Charge Capacity." If these two values are the same, the "Battery Wear" will be 0%. Generally, for newly manufactured or poorly maintained batteries, the "Full Charge Capacity" may be less than the "Design Capacity," resulting in a battery wear of 1%. This indicates that the battery has not been fully charged, and a "Full Discharge and Charge" process (discharging completely followed by uninterrupted charging for over 12 hours) is required to unlock the battery's full potential. This process is known as "battery activation," and power management software, such as Lenovo ThinkPad's, includes a "Power Gauge Calibration" function that serves a similar purpose.

  In conclusion, it is advisable to avoid over-discharging batteries and adhere to proper battery maintenance and usage practices. These methods are attempts to rectify over-discharge issues, but there is no guarantee of 100% success. Moreover, lithium batteries are already activated during production testing. Consumer misconceptions about batteries contribute to the demand for such services.

  If your smartphone battery is over-discharged, unable to power on, or charge, activation is necessary. The two methods mentioned earlier, using a universal charger for approximately 20 minutes or seeking professional help from a repair shop with a slightly higher voltage source (e.g., 12V), can be employed. The latter involves applying the positive and negative poles of the power source to the corresponding poles of the battery for several seconds or even minutes to restore functionality. After activation, you can resume using direct charging as before, but the impact on battery life remains uncertain.

  If the aforementioned methods prove ineffective and there is no battery malfunction, consider using a regulated power supply for activation. Connect the black wire to the battery's negative pole and the red wire to the positive pole, adjusting the charging voltage to 3.8V. For devices using lithium batteries, there is no need for a 12-hour initial charge, as this is unnecessary.

  In summary, maintaining and using batteries correctly is crucial for preserving battery performance and lifespan.