Summer is here. The lead-acid battery of an electric vehicle easily shows faults such as the charger not switching to the green light or the case swelling, which end battery life prematurely. What causes such faults, and how can they be avoided? Let us explain.

1. Frequent use of unqualified chargers

As the device that charges the battery, a charger's parameters must meet the matching requirements of the battery, especially the key parameters: the maximum voltage controls the charging stress on the battery, and the changeover current controls the charging time. Both must comply with the battery manufacturer's requirements, so choosing a qualified, matched charger is very important. Charger quality on the market varies widely at all prices, so consumers are advised to buy a branded charger with a good reputation and solid quality.

2. Using the wrong charger

For example, consumers often use a 48V20Ah charger on a 48V12Ah battery. Although it can charge and switch normally, the starting charging current is too large, raising the electrolyte temperature and causing active material to shed from the plates; over long-term use this easily leads to the light not switching or the case swelling. Therefore, use the charger strictly according to the battery matching requirements, and also try to avoid frequent use of street fast-charging equipment. Occasional use can relieve an urgent need, but street fast chargers have an even larger starting current and cause more serious damage to the battery.

3. Unreasonable charging habits

Unreasonable charging habits mainly show up as over-long charging or too-frequent charging. After the battery runs down and is charged to saturation, the usual charging time is 8-12 hours. Less than this leaves the battery undercharged; more than this keeps the battery at high voltage for too long and invites the light not to switch or even the case to swell. Frequent charging makes a lead-acid battery extremely prone to sulfation, which increases internal resistance, raises the heat produced during charging, and results in the light not switching or swelling. Therefore charging time and frequency must be strictly controlled. We suggest arranging charging time reasonably according to actual use: after the charger turns green, continue float charging for 2 hours at most and then end charging; unless conditions are special, it is best not to charge more than once a day.

4. Poor charging environment

This point is ignored by many users. If the ambient temperature during charging is too high, even a normal charger with a normal battery may fail to switch to green. The charging environment should meet these conditions: ventilated and dry, never in scorching direct sunlight, and not too hot (the closer to 25 degrees Celsius, the better). Also, while the electric vehicle is charging, avoid covering the vehicle body so that gases can escape normally.

5. Unreasonable riding habits

In use, a lead-acid battery should stop discharging when roughly 30% of the charge remains. Yet quite a few consumers like to use the battery completely empty before recharging. Frequent full discharge creates voltage differences among the individual cells, that is, inconsistent state of charge across the pack. When cells are unbalanced, some of them will be overcharged during charging, which again leads to the light not switching or the case swelling.

Finally, remember that with batteries, prevention comes first. If you suspect a problem, take the battery to an official after-sales service point at the first opportunity for inspection and repair to rule out faults, and fix or replace early to avoid the inconvenience of a battery suddenly failing during use.