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◆ What's the capacity of the battery?

A: The capacity of the VRLA battery means that when the battery is full charged and discharge at some condition to the stated end voltage, the capacity is released out, the unit is Ah. For example, when the battery discharges at 1A current for 1 hour, that's the 1Ah capacity. If the battery discharges at 4A current for 3 hours to the end voltage, the released capacity is 12Ah.

◆ What is EPV (Cut-Off Voltage/End Point Voltage)?
EPV is the battery end load voltage in the condition of discharge. Many kinds of standards rule EPV definitely in different discharge rates and temperatures. EPV is different according to different discharge rates: it is low when discharge in high current, contrarily, it is high when discharge in low current.

◆ What is the self-discharge rate of batteries?
A: The self-discharge, also known as charge retention capacity, that means when it is in open circuit state, the maintain ability of battery's storage electricity under certain environmental conditions .During storage time, the rate of capacity loss is called self-discharge rate. It is mainly affected by the manufacture technology, materials, storage conditions and other factors, which is an important parameter to measure the battery's performance.

◆ What is discharge hour rate?
Discharge hour rate is mean the discharge capacity will decrease according to increase of discharge current under condition that the active substance quantity keep unchanged. So the discharge rate should be specified when scale the discharge capacity. Discharge rate include hour rate and current rate. Hour rate(time rate) is the needful time when finished discharge the capacity under a definited current, different VRLA battery have different discharge rate standard; Current rate is also named as double rate, it is meaning that discharge current is the double rate of rating capacity.

◆ Why the batteries need to be stored for a certain time before delivery? 
A: The storage capability is an important parameter for checking the stability of general capability. After a certain period storage, the variety of capacity and inner resistance is allowed. And the storage can level off the electrochemistry performance of inner component, so that we can know the extent of self-discharge capability, then pick out the batteries with short circuit (caused by fast dropping of OCV) and micro short circuit, so the battery quality can be ensured.

◆ Why the battery cannot be charged(fully charged)?
A:  After using for a few months, the battery can not be charged, because the occur of Lead sulfate (PbSO4), sulfation as it is commonly called. Generally speaking, sulfation is the prime cause of battery failure and loss of capacity especially

Sulfation is a natural occurrence in all lead/acid batteries including sealed, gel-cell, and recumbent batteries.  It the prime cause of early battery failure and is when the sulfur in the sulfuric acid forms sulfur crystals attach to the lead plates and then act as an "insulation" keeping the battery from accepting a charge.  Typical chargers and even "smart or automatic chargers" can not overcome this phenomena and thus the battery is discarded as "not being able to hold a charge".  Sulfation occurs far more readily in hot climates where batteries aren't frequently used or kept up to voltage.   Sulfation can occur in brand new batteries in as short of time period of a few weeks or a few months. 

◆ How to avoid the plate sulfation?
1. Using an extended charge, known as an equalization charge to slow-down the rate of sulfation
2. Avoid low cutoff voltage discharges
3. Recharge immediately after discharge
4. Completely charged before using
5. Please shelve the battery after it’s fully charged