The service life and performance of lead-acid batteries (such as car starter batteries, electric vehicle batteries, etc.) are closely related to daily maintenance. Scientific regular maintenance can effectively extend their cycle times and avoid problems such as swelling and leakage. The following are detailed regular maintenance methods, covering the core points of different usage scenarios:
1、 Daily basic check: once a week/month, promptly detect abnormalities
Basic inspection is the first step in maintenance, which can quickly identify visible issues such as appearance and connection. It is recommended to conduct it once a week (during high-frequency use) or once a month (during low-frequency use).
Appearance inspection:
Observe whether the battery casing has bulges, deformations, or cracks, and whether the electrodes (positive and negative poles) are corroded or leaking (white crystals may appear due to lead sulfate precipitation). If the shell is found to be damaged or leaking, it should be immediately stopped (the leaking sulfuric acid is corrosive and needs to be cleaned with baking soda water), and cannot be continued to be used.
Connection check:
Check if the connecting screws between the electrode and the wire are loose or oxidized. Oxidation can cause poor contact and generate heat during charging/discharging. It is necessary to sand off the oxide layer with sandpaper and then tighten it again; If the screw is loose, it needs to be tightened with a wrench (note that the positive and negative poles should not be short circuited, and insulated gloves can be used during operation).
2、 Charging management: core maintenance item to avoid overcharging/undercharging
The "life killer" of lead-acid batteries is mainly "overcharging" and "undercharging", which need to be charged according to the usage scenario specifications. It is recommended to charge them in a timely manner after each discharge and do "balanced charging" once a month.
Avoid undercharging:
After discharging a lead-acid battery, the electrode plate will generate lead sulfate. If it is not charged for a long time (under charged), the lead sulfate will crystallize and "solidify" (i.e. "sulfide"), resulting in a decrease in electrode activity and a significant reduction in capacity (such as electric vehicle batteries, which may decay to 50% in one year if they are frequently used until they run out of battery or unplugged halfway through charging).
Correct practice: Charge in a timely manner when discharging to 20% -30% of the remaining capacity (such as for electric vehicles, charge when the dashboard displays 1-2 grids of battery remaining), do not wait until there is no battery left before charging; Fully charge at once during charging, do not interrupt midway.
Avoid overcharging:
Overcharging can cause the electrolyte inside the battery to "electrolyze", producing a large amount of hydrogen and oxygen (which is prone to bulging). At the same time, the water in the electrolyte is consumed, the concentration increases, and the electrode plates are corroded (such as car batteries, if overcharged for a long time with poor quality chargers, it may bulge after 3-6 months).
Correct practice: Use the original or matching charger (the voltage and current of the charger should be consistent with the battery parameters, for example, for a 12V 7Ah battery, use a 12V 1-2A charger); Do not charge for too long. After the regular battery is fully charged (the charger indicator light turns green), float charge for 1-2 hours, and do not exceed 12 hours; Avoid charging in high temperature environments (such as in cars exposed to direct sunlight in summer or in rooms above 40 ℃).
Balanced charging (once a month):
When multiple batteries are used in series (such as a 48V battery pack for an electric vehicle, consisting of four 12V batteries), there may be "capacity imbalance" due to individual differences in the batteries (a certain battery is fully charged/discharged first), which can lead to overcharging and undercharging of some batteries in the long run.
Method: Charge once a month with a "balanced charger" (or original charger with balancing function), which will be recharged with low current in the later stage to make all batteries fully charged and reduce unbalanced losses.
3、 Discharge management: Control the depth and frequency of discharge to avoid high current discharge
In addition to charging, the standardization of the discharge process is also important, especially to avoid "deep discharge" and "high current discharge" and reduce electrode damage.
Control discharge depth:
Single discharge should not exceed 80% of the battery capacity (i.e. "discharge depth ≤ 80%"), for example, a 100Ah battery can discharge up to 80Ah of electricity per discharge (if discharging with 10A current, do not exceed 8 hours). Deep discharge (releasing over 90% of capacity) will intensify the sulfurization of the electrode plate and shorten its lifespan.
Avoid high current discharge:
High current discharge (such as frequent starting of cars, sudden acceleration/climbing of electric vehicles, and sudden tightening of the accelerator) can cause a large amount of lead sulfate to be produced instantly on the electrode plate, and the distribution is uneven, which can easily form thick crystals on the surface of the electrode plate and accelerate vulcanization.
Method: Do not frequently turn the key when starting the car (with an interval of ≥ 30 seconds between each start); When driving an electric vehicle, avoid sudden acceleration and overloading (if the load exceeds the rated value, it will increase the discharge current), slow down in advance when climbing, and apply force smoothly.
4、 Electrolyte maintenance: For "maintainable batteries", add distilled water
Lead acid batteries are divided into "maintenance free batteries" and "maintainable batteries" (with detachable liquid filling holes on the shell). Maintainable batteries need to regularly check the electrolyte level and replenish distilled water (do not add tap water or electrolyte).
Determine if it is necessary to supplement:
Unscrew the top liquid filling hole cover of the battery (usually 6-8, corresponding to each cell), and observe whether the electrolyte level is below the "MIN" mark. If it is below, liquid needs to be replenished.
Correct supplementary method:
Only distilled water (or specialized lead-acid battery replenishment solution, which is essentially high-purity water) can be added, and tap water (containing impurities that can contaminate the electrolyte) cannot be added, nor can electrolyte be added (which can cause high electrolyte concentration and corrode the electrode plate); Just add it to the 'MAX' mark, don't fill it too full (it will overflow during charging); After supplementation, tighten the liquid filling hole cover and wipe off any residual liquid from the outer shell.
5、 Storage and maintenance: When not in use for a long time, do a good job of "electricity protection+moisture prevention"
If the battery is not used for a long time (such as when the car is stopped in winter or when the electric vehicle is idle), it needs to be disposed of in advance to avoid sulfurization or self discharge that may cause it to be scrapped. It is recommended to check the battery level once a month.
Fully charged before storage:
Before long-term storage, fully charge the battery (to avoid being under charged during storage), and then disconnect it (such as disconnecting the negative terminal of the battery in a car or unplugging the battery plug in an electric vehicle) to reduce self discharge losses.
Regularly replenish electricity:
Lead acid batteries will self discharge (with a monthly self discharge rate of about 10% -15%), and long-term storage requires charging once a month to maintain a battery level of 70% -80% (fully charged storage is also acceptable, but not lower than 50%), to avoid sulfurization due to low battery levels.
Storage environment:
Keep in a dry, ventilated, and cool place (preferably at a temperature of 5-25 ° C, avoiding temperatures below 0 ° C or above 30 ° C), away from sources of fire (the battery will produce a small amount of hydrogen gas when discharging, which poses a risk of fire), and avoid direct sunlight or rain (moisture can cause electrode corrosion); When storing, wooden or plastic boards can be placed on top (insulated and moisture-proof), and should not be placed directly on cement floors (cement floors have fast thermal conductivity and large temperature changes, which may accelerate self discharge).
Summary: The "Core Principles" of Maintaining Lead Acid Batteries
Don't undercharge or overcharge: Charge promptly after each discharge, stop when fully charged, and use a matching charger;
Do not discharge too deeply or with high current: do not discharge too aggressively to avoid rapid acceleration/frequent starting;
Regularly check and replenish in a timely manner: check the appearance/connection, maintain the battery with distilled water, store it for a long time and charge it monthly.
By following the above maintenance methods, the service life of ordinary lead-acid batteries can usually be extended from 1-2 years to 2-3 years (or even longer), greatly improving their cost-effectiveness.
