Electric vehicles are gradually becoming an important means of transportation for many citizens. However, because most people do not understand the principles of battery charging and discharging and do not charge them correctly, their batteries often fail after only about a year of use. So, how long should an electric vehicle be charged? Are you properly maintaining your electric vehicle battery? Here, we remind everyone that in addition to choosing a reputable electric vehicle battery brand, we should also pay attention to the charging time. Only by paying attention to and properly maintaining your electric vehicle battery in daily life can you extend its lifespan.
How long does it take to charge an electric vehicle?
1. After buying a car or replacing the battery, the battery should have about 80% charge. You should charge it as soon as you get home, and the charging time should be about 4 hours after the charger indicator light changes.
2. From now on, you should charge the battery daily (after riding 10 kilometers for 36V and 15 kilometers for 48V), but do not charge for too long; one hour after the charger indicator light changes is ideal. It's better to undercharge than overcharge, otherwise the battery will swell and bulge due to dehydration, causing irreparable damage.
3. Do not allow water to enter the battery compartment, as this may cause short circuits in the batteries inside the casing.
4. Once a month, fully discharge the battery (ride until the low voltage light comes on), then charge it for 12 hours.
5. If possible, swap the individual cells in the entire battery pack. For batteries past their warranty period (especially in summer), add 3-4 ml of deionized water (Wahaha purified water is also acceptable) to each individual cell every three to four months.
6. If you find that the charger light does not turn green or turns green as soon as you start charging, be sure to check if there is a problem with the charger or if it has lost water.
7. The discharge and charging ports of the entire battery pack should be kept clean at all times to prevent copper rust from forming at the contact points, which could cause poor contact, overheating, and damage.
8. If the vehicle has pedals, use your feet to start; avoid excessive load and accelerate smoothly. Do not start the vehicle with the electric starter as soon as you get in.
Is it okay to fully discharge the battery before recharging it?
Since deeper and shallower discharges significantly increase the number of battery cycles, according to this theory, frequent charging is beneficial to cycle life. However, the chargers currently widely used in the market suffer from high failure rates, poor reliability, and low accuracy due to factors such as price and technological limitations. Therefore, frequent charging can sometimes actually negatively impact battery lifespan. While fully discharging the battery before recharging reduces the number of charging cycles, the inherent differences between individual cells during discharge can lead to over-discharge in some cells. Over-discharged batteries have significantly reduced charging acceptance, causing undercharging. Furthermore, fully discharging before recharging puts the charger under heavy load for an extended period, potentially damaging it. Therefore, considering all these factors, we believe that charging the battery when it has discharged 50-70% of its capacity is more reasonable and beneficial for battery life.
What are the harmful effects of overcharging and undercharging a battery?
Overcharging occurs when the charging current of a battery exceeds its acceptable current; the excess is the overcharge. A major consequence of overcharging is the side reaction of water electrolysis. Because oxygen transfers from the positive electrode to the negative electrode and undergoes oxygen recombination, heat is generated. Therefore, the overcharge effectively converts into heat, raising the battery temperature. If left uncontrolled, this can lead to significant water loss, and in severe cases, thermal runaway, drastic capacity reduction, and even deformation. Undercharging, simply put, occurs when the battery is frequently undercharged. This causes the gradual formation of coarse, hard lead sulfate at the electrodes, which is almost insoluble, a condition known as irreversible sulfation. Ordinary charging methods are ineffective, resulting in rapid capacity decay with each repetition.
Comparison of lead-acid and lithium-ion batteries for electric vehicles
Lead-acid batteries generally have a durability of less than 300 deep charge/discharge cycles, exhibit memory effect, and have a lifespan of around two years. Furthermore, lead-acid batteries contain liquid; if the battery becomes hot or charging time shortens after a period of use, the liquid needs to be replenished. Lithium-ion batteries are more durable, consume less power, can withstand over 500 charge/discharge cycles, have no memory effect, and generally have a lifespan of 45 years.
Its volume and mass are generally around 1630 kg, making it relatively large. Others weigh around 2.53 kg and are relatively small, making them easy to ride and transport.
Lead-acid batteries cost around 450 yuan with a one-year warranty. Lithium-ion batteries are relatively more expensive, costing around 1000 yuan, but have a two-year warranty.
Using the same 48-volt battery, a vehicle can travel 3040 kilometers on a full charge. Speed depends primarily on the size of the motor used. (Similar to sulfuric acid batteries.)
Battery capacity around 20 amps to 810 amps
While green and environmentally friendly practices may involve pollution during production, improper recycling can also cause pollution. (The last sentence appears to be incomplete and possibly refers to a different topic.)
How to maintain an electric vehicle battery?
1. First and foremost, the battery must not come into contact with water. If the battery gets wet in the rain or gets wet while charging, wipe it dry with a clean cloth immediately.
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2. Do not overload the vehicle, especially not on uphill sections, as a sudden increase in current can damage the battery;
3. Battery charging time must be even; do not charge for 6 hours one night and 8 hours the next. Always charge the battery fully in one go; using it incompletely will reduce battery life.
4. Using an electronic repair kit to repair electric vehicle batteries can effectively decompose the lead sulfide crystals inside the battery, extending its lifespan (proven to extend battery life by approximately 2 years). For batteries that have been used for about one year, it can effectively restore them to about 80% of their new battery condition, allowing for another year of use.
Common Faults and Troubleshooting
Q: Do electric vehicle batteries need maintenance?
A: Yes. During the charging process, batteries produce hydrogen and oxygen gases. Most of these gases recombine with water inside the battery, with only a small portion being expelled through the safety valve. Over time, this can lead to water loss in the battery. Therefore, it's best to have your electric vehicle's battery refilled at a battery shop or repair shop after 8-10 months of use, or if the battery compartment gets hot during charging.
Q: Is the short driving range of electric vehicles always a problem with the battery?
A: Not necessarily. While battery aging and reduced capacity can shorten driving range, the following issues, which are not related to the battery, can also lead to a shorter driving range:
1. When motor efficiency decreases, the amount of useless work done increases, wasting electricity and shortening the driving range;
2. Inferior chargers undercharge the battery daily, resulting in insufficient battery capacity and reduced driving range;
3. A faulty controller can cause excessive starting current in electric vehicles, wasting electricity and resulting in a shorter driving range.
4. Inferior electric vehicles may have excessive friction coefficients in their moving parts or excessive mechanical transmission resistance, which can also lead to wasted electricity and a shorter driving range.
Q: What precautions should be taken when using electric vehicles in the summer?
A: 1. Avoid exposure to high temperatures and direct sunlight; charging in high-temperature environments is strictly prohibited.
2. Avoid charging immediately after driving in high temperatures, and avoid charging for too long (normally around 8 hours);
3. If the power supply box gets hot or the green light does not turn on while the battery is charging, the battery or charger should be inspected and repaired at a battery store or repair shop as soon as possible.
Q: What problems might occur when using electric vehicles in winter, and how can they be prevented?
A: 1. You will notice a significant decrease in driving range when using an electric vehicle in winter (more noticeable in northern regions), which is normal;
2. In low-temperature environments, the battery's charging acceptance capacity decreases, and the electrolyte viscosity increases, leading to increased resistance to electrochemical reactions, which in turn reduces the battery's capacity. Therefore, you should avoid leaving your electric vehicle outdoors overnight or charging it in low-temperature environments during winter.
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Precautions
1. The power supply enclosure is too sealed, preventing hydrogen gas from escaping during the final stages of charging;
2. Loose, aged, or exposed power cables may cause sparks when the key is turned on to discharge, or uneven road surfaces may cause sparks in the wiring that ignite the hydrogen gas.
3. A loose fuse holder on the power supply unit may cause it to overheat or spark during battery charging and discharging, igniting hydrogen gas and causing gas expansion that could rupture the power supply cover.
4. Batteries must not be placed near open flames or high-temperature heat sources. Batteries must not be thrown into fire or submerged in water. Direct exposure to sunlight or charging is strictly prohibited.
5. Batteries must not be placed in sealed containers; good ventilation should be maintained.
6. If the battery casing is found to be cracked or leaking, the battery must be replaced;
7. The electrolyte is an acidic solution. If it gets on your skin or clothing, rinse immediately with plenty of water. In severe cases, seek medical attention.
8. The battery must not be short-circuited or used upside down.
Methods for repairing electric vehicle batteries
1. Re-grouping: After the entire battery pack is damaged, we often perform charge and discharge tests. During the inspection, we often find that 50% of the batteries in a group are not damaged. The reason is that in the series-connected battery pack, the failure of individual batteries causes the overall battery pack's function to deteriorate, resulting in a decline in the overall battery pack's performance.
2. Water Replenishment: Replenishing water on a battery that has been used for about 4 months can extend its lifespan by an average of more than 3 months. It should be noted that after each water replenishment, the battery undergoes an overcharge process, transitioning from a near-starved state to a starved state. This overcharge is beneficial for increasing battery capacity.
3. Desulfation: Battery repair equipment is used to desulfate the batteries.
4. Microparticle generator: A microparticle generator is connected in parallel to the battery to repair it. This method is good for battery repair, but because the repair is thorough, it often completely eliminates the possibility of battery sulfation if there has been no over-discharge.
5. Comprehensive Repair Method: Regularly inspect the battery, promptly desulfurize and replenish water, charge individual batteries, and reassemble the battery pack. Battery instructions state that if it is maintenance-free, generally do not add water. If water must be added, first check the electrolyte density of the electric vehicle battery and select the appropriate concentration or no concentration of water to add, depending on the specific situation. This will increase battery capacity or extend its lifespan.
