Lead acid batteries and valve regulated sealed lead-acid batteries (VRLA batteries) belong to the same lead-acid battery system, but there are significant differences in structure, performance, and application scenarios. The following comparative analysis is conducted from multiple core performance dimensions:
1、 Basic concepts and structural differences
Traditional lead-acid batteries:
Open or semi open structure with openable liquid filling holes, electrolyte is liquid sulfuric acid, and distilled water needs to be regularly replenished to maintain the liquid level. Gases (mainly hydrogen and oxygen) can freely escape.
Valve regulated sealed lead-acid battery (VRLA):
Fully sealed structure, no filling hole, electrolyte is adsorbed in the partition (such as glass fiber cotton) or in the form of gel (gel battery), and gas discharge is controlled through the built-in one-way exhaust valve (only opened when the internal pressure is too high), realizing the "maintenance free" feature.
2、 Core performance comparison
Performance indicators: Traditional lead-acid battery valve regulated sealed lead-acid battery (VRLA)
High maintenance requirements: Regular checks of electrolyte level and replenishment of distilled water are necessary; Clean electrode low: No need for fluid replenishment, only regular inspection of appearance and voltage ("maintenance free")
Poor sealing performance: electrolyte is prone to leakage, gas evaporates freely. Excellent: fully sealed design, electrolyte is not prone to leakage, and gas emissions are controllable
Installation direction restricted: It needs to be installed upright to prevent electrolyte overflow. Flexible: It can be installed horizontally or diagonally (some models allow ± 45 °)
Short cycle life: typically 300-500 cycles (100% deep discharge) Long: typically 500-1200 cycles (depending on type and usage conditions)
High self discharge rate: monthly self discharge rate of about 15-30% Low: monthly self discharge rate of about 5-15% (colloidal batteries are even lower)
Low charging efficiency: about 70-80% High: about 80-90% (stronger charging acceptance)
Low temperature performance is average: the capacity decreases significantly at low temperatures, and the discharge capacity is slightly better. Colloidal VRLA batteries have better low-temperature performance than traditional batteries, but are still affected by low temperatures
Low cost: simple materials and manufacturing processes, high cost: sealing structure and special partitions increase costs
Low safety: electrolyte leakage may cause corrosion, gas escape poses a high risk of explosion: sealing design reduces corrosion and explosion risks, but overcharging may cause valve loss of control
Applicable scenarios include car starter batteries, forklifts, fixed power sources (requiring maintenance space), uninterruptible power supplies (UPS), communication base stations, emergency lighting, and small energy storage (in maintenance free scenarios)
3、 Analysis of Key Performance Details
Cycle life and deep discharge tolerance
Traditional lead-acid batteries: Deep discharge (discharge to below 20%) has a significant impact on lifespan and is more suitable for shallow cycling scenarios (such as car start-up, where discharge depth is usually less than 20%).
VRLA batteries, especially colloidal types, have stronger deep discharge tolerance and are suitable for scenarios that require frequent charging and discharging (such as UPS, solar energy storage), but excessive discharge can still shorten their lifespan.
Gas emissions and environmental friendliness
Traditional batteries: release a large amount of hydrogen and oxygen during charging, requiring good ventilation, otherwise it may cause explosions; Electrolyte leakage can pollute the environment.
VRLA battery: Through the "oxygen cycle" design (where oxygen is combined with water at the negative electrode), gas production is reduced, and only exhausts during overcharging or high temperatures, resulting in better environmental and safety performance.
temperature sensitivity
Both are sensitive to high temperatures (which can accelerate electrode corrosion and electrolyte evaporation), but VRLA batteries have a higher risk of pressure accumulation at high temperatures due to their sealed structure, requiring strict control of the ambient temperature (recommended around 25 ℃).
4、 Summary and Suggestions for Applicable Scenarios
Traditional lead-acid batteries: suitable for cost sensitive, regularly maintained, and limited installation direction scenarios (such as car starting, industrial forklifts).
VRLA batteries: suitable for scenarios that require maintenance free, flexible installation, and high safety requirements (such as communication base stations, home energy storage, and backup power for medical equipment), but attention should be paid to avoiding overcharging and high temperature environments.
Overall, VRLA batteries are an upgraded version of traditional lead-acid batteries, solving maintenance and safety pain points through sealing technology, but at a higher cost, requiring a balance between performance and economy based on actual needs.
