Maintenance-free batteries have the characteristics of low price, easy portability, and large capacity, and have been used in emergency lights, flashlights, UPS power supplies, motorcycles, electric bicycles, and electric tricycles. However, if it is used improperly, it will cause damage to the battery and even be scrapped. In fact, as long as proper repairs are made, the capacity of most batteries can be restored to a certain extent.

1. Common problems and solutions

1. The maintenance-free battery (hereinafter referred to as the battery) basically does not produce gas during charging, and can be in a sealed state, eliminating the need for maintenance work such as adding acid. However, it is impossible for the battery not to generate gas at all during the charging and discharging process. In order to release the gas, the battery cannot be completely sealed. Pry open the upper part of the battery, in order to release the gas, the battery cannot be completely sealed. Pry off the plastic cover on the upper part of the battery, you can see that each small battery has a filling hole covered with a rubber cap, and the water in the battery can evaporate through the rubber cap. Even if the battery is not in use, the water will evaporate, resulting in a decrease in battery capacity. In severe cases, the battery will dry out and cannot be charged and discharged. For this type of battery, most of the capacity of the battery can be restored by simply adding distilled or purified water to the battery and performing several charge-discharge cycles.

For example: a 12V7.2Ah battery, which is not used for a long time, discharges after charging to 14V, and the short-circuit current is only about 300 mA. Open the top cover to check, the liquid is almost dry, inject distilled water and perform charge-discharge cycles twice, the capacity is restored to 84%, and it can work normally.

2. When the battery is discharged, the concentration of sulfuric acid and the specific gravity of the electrolyte decrease. After complete discharge, the specific gravity at 15°C drops to 1.11. Generally, the specific gravity rises during charging, and the specific gravity after fully charged is 1.25~1.26 in summer and 1.27~1.28 in winter. Because the battery is in a sealed state, when in use, you can only judge whether it is fully charged or fully discharged according to the voltage of the battery. When the 6V and 12V batteries are fully charged, the voltages are 6.8V~7V and 13.6V~14V, respectively. When fully discharged, the voltages of the 6V and 12V batteries are 5.3V and 10.6V, respectively. If the battery is over-discharged or in a semi-discharged state for a long time, the battery will be vulcanized. The vulcanized battery cannot be eliminated by adding distilled water and conventional charging. Only when the concentration of sulfuric acid in the electrolyte is charged, the vulcanization can be eliminated.

(1) If the vulcanization of the battery is not serious and the capacity does not decrease much, the battery can be charged for a long time with a small current (0.05A or less).

(2) If the vulcanization of the battery is serious, it can be charged to the highest voltage (6V battery is charged to 7V, 12V battery is charged to 14V), the electrolyte in the battery is drawn out with a syringe, and then injected with distilled water to dilute the electrolyte. After charging for 1 to 2 hours, draw out the electrolyte, inject distilled water, and repeat the above operations until the specific gravity of the extracted electrolyte no longer increases significantly (generally 2 to 3 times). At this time, try to draw out the reverse electrolyte, and then inject sulfuric acid with a specific gravity of 1.25~1.28 according to the ambient temperature. If the specific gravity is small, the electrolyte can be drawn out again and injected with sulfuric acid to make the specific gravity of the electrolyte meet the standard. Note that the electrolyte injected into the battery should not be too much. After the sponge-like substance in the battery is fully absorbed with the electrolyte, the excess electrolyte is drawn out, and the repair work is completed.

Example: A Sony BP60 3Ah battery was used as a power source for 3/4-inch cameras in the 1980s, and the battery was severely vulcanized. After repairing with the above method, the capacity is restored to 2.2Ah.

3. The battery is generally composed of several people's batteries in series (3 for 6V batteries and 6 for 12V batteries), and several batteries in series are required to have the same capacity and charge-discharge characteristics. However, the consistency of each battery is relatively poor for non-brand and poor quality batteries. After the battery is fully charged, from the perspective of the entire battery, the voltage has been charged enough, and the poor quality battery has been overcharged. When discharging, the voltage of the battery dropped to 5.3V and 10.6V, but the poor quality battery was over-discharged. Poor quality batteries have poor performance, and in this case, they are more likely to be vulcanized, resulting in a decrease in battery capacity and early scrapping. To repair this kind of battery, the poor quality battery should be found first. The method is to drill a Φ6mm hole on the upper cover of the battery corresponding to each battery connection bridge (usually in the middle or slightly to the side of the two rubber caps), and the depth of the hole is just drilled to the lead connection bridge (do not drill through) . Then use a Φ1.5mm drill to drill a small hole with a depth of about 2mm~3mm on the connecting bridge (do not drill through). Then use a piece of copper coin with a length of about 40mm and a diameter of about 1.2mm that has been completely plated with solder to drive into the small hole of the connection bridge, and drop the melted rosin or asphalt around the copper coin (because sulfuric acid is very corrosive to the copper coin, and corrosion occurs The copper sulfate is harmful to the battery. Plating tin on the copper coin can make the contact between the copper coin and the connection bridge more closely, and protect the copper coin from being corroded by the electrolyte. The drop of rosin is to further protect the copper coin from being corroded by the electrolyte). A 12V battery can enter up to 5 copper coins, which means that the positive and negative electrodes of each small battery are drawn out, and the voltage of each small battery and the specific gravity of the electrolyte can be checked. For small batteries that have been vulcanized, the above methods can be used to repair them separately.

4. Some battery connection bridges or the external lead wires of the battery are broken (in most cases, the positive and negative lead wires are broken), and the battery cannot work. A deformed battery can only be repaired by finding the broken part. Using the above method of plated copper coins, use a multimeter to find the battery with abnormal voltage or small output current, and the breaking point is on the battery. After finding it, open a hole in the plastic cover at the break. The size of the hole should be enough to allow a soldering iron to penetrate into the break for welding, but it should not be too large. After welding, check that the connection is normal, seal the open hole with plastic or epoxy resin, and then use the above method to revive, and the battery can be put into work again.

5. If there is a short-circuit fault inside the battery, the short-circuit point can be burned with low voltage and high current. If the active material falls off (indicated by the brown material in the withdrawn electrolyte), it means that the battery life has ended, and this type of battery does not need to be repaired. However, if only one or two of the batteries are at the end of their life, these two batteries can be short-circuited, and the remaining batteries can still be used as lower-voltage batteries.

Powered & Powerful!

Distributors and OEM business are warmly welcome.
     Get connected with professional lead acid battery manufacturer,
      www.gembattery.com
     sales@gembattery.com
     WhatsApp: +8615959276199