Discharge Capacity of C10 12v100ah Decreasing New Solution

News 2023年2月22日 33

A battery manufacturer encountered a problem. A batch of batteries experienced a decline in capacity after charging cycles.


I hope you are fine

We produce 12V-VRLA batteries.

After the production of 100Ah Batteries, we test the discharge capacity (C10) of it for several cycles and we see the C10 capacity is decreasing. The results of continuous series of cycles are:

Cycle 1: 110AH

Cycle 2: 108AH

Cycle 3: 102AH

Cycle 4: 99AH

Cycle 5: 98AH

Cycle 6: 89AH

Cycle 7: 88AH

Cycle 8: 86AH

Cycle 9: 84AH

Cycle 10: 82AH

Cycle 11: 80AH

As you see the result of the C10 Capacity test is decreasing.

Lead-acid battery
Lead-acid battery

After the C10 capacity test finishes, we start the C5 capacity test series for some cycles. As a result, we see no decrease in capacity tests and mostly they are in the same range (All of them about 80AH).

Our question is:

Why the result of C10 cycles is decreasing, however when we test C5 cycles immediately after C10 tests, do the C5 cycles have the same results?

Is it because of the formation profile?

Is it because of AGM?

What is the reason?

Causes of lead-acid battery capacity decline

1. The safety valve of the battery fails: the battery casing is cracked and the pole leaks. Or the safety valve is blocked and cannot release pressure.

2. The temperature of the operating environment is too high: the high temperature causes the internal pressure of the battery to increase, and the liquid seeps out. Too little acid reduces battery capacity.

3. Defects in battery design: internal corrosion of lead-acid batteries

4. Negative plate sulfuric acid failure: the formation of irreversible lead sulfate reduces the capacity of lead-acid batteries.

Battery charging is generally carried out according to the current size of 0.1C. C means the rated current of the battery. Such as a 1000mAh battery, the charging current should be 100mA. In this way, it is impossible for you to change the charging current of 0.5A to 1.0A. Even if there are no other accidents, the battery life will be shortened due to excessive charging heat. This is the basic requirement. Specifically, battery charging is divided into three stages: constant current charging, constant voltage charging, and silk current charging (the user does not have to worry about how the charger realizes the conversion of these charging stages).

The charging current mentioned above is the constant current charging current. Constant voltage charging has different charging voltages according to different voltage levels. Therefore, it is not enough for you to choose a charger based on the current size alone. For example, a charger is for charging 12V batteries, but it cannot charge batteries with voltage levels such as 24V or 6V. Slight current charging is also different depending on the battery. It is also generally called float current.

Its size is closely related to the battery capacity. For example, the normal charging current (constant current charging current) of a 1000mAh mobile phone battery may not be as large as the floating charging current of a lead-acid battery with a larger capacity. Too large is most likely to cause battery overcharge. In short, you must be careful when choosing a charger. The voltage level and current capacity should be matched as much as possible. If it is a lithium (ion) battery, you need to be more careful. Unless it is urgently needed, don’t charge it if it doesn’t match.

Because once damaged, the price to bear is too high. Finally, for some mobile phone batteries, there are some so-called universal chargers, but they should be used with caution. It is recommended not to fully charge the battery, and end it in time when it is enough because you don’t know how long it will end charging (standard). Battery protection, the most basic are two: do not overcharge, do not consume excessive power. If these two rules are violated, the battery may not be damaged immediately, but may also lead to a decrease in capacity.

Caloong New Energy’s sister company ZXferroalloy supplies ferroalloys.