Dry-charged batteries are what's known as "water tanks." They don't come with dilute sulfuric acid at the factory; you need to add dilute sulfuric acid and then fast charge them for 30 minutes to 1 hour before activating them for use.
Wet-charged batteries are also known as maintenance-free or low-maintenance batteries. They are pre-filled with dilute sulfuric acid and fully charged at the factory, ready for immediate installation. However, if stored for an extended period (usually 6 months), manual recharging is required.
Maintenance-free batteries do not have a liquid filler cap, meaning that liquid cannot be added during use.
The low-maintenance battery has six fluid inlet valves. Many people mistake this type of battery for a water-filled battery, but they are completely different. This type of low-maintenance battery is commonly used in original equipment vehicles, especially Japanese cars. Because water can be added when the fluid level drops, if the owner uses it properly (checking the fluid level regularly), its lifespan will definitely be longer than that of a maintenance-free battery.
Wet-charged lead-acid batteries are the most common type of battery today. They are manufactured in the factory with the positive and negative plates installed, electrolyte added, and then sealed and shipped without being pre-charged. Users need to charge them before using them.
Dry-charged batteries are manufactured in the factory using chemical methods to fully charge the positive and negative plates. They are shipped without being filled with electrolyte or packaged. After purchase, users only need to fill them with electrolyte and then use them without recharging. These batteries are suitable for long-distance transportation.
Currently, dry-charged batteries are mainly used in large trucks. Maintenance-free batteries are commonly used in electric vehicles, small cars, and sedans.
Dry-charged battery: Its full name is dry-charged lead-acid battery. Its main feature is that the negative plate has a high energy storage capacity. In a completely dry state, it can retain the energy it has accumulated for up to two years. When using it, you only need to add electrolyte and wait 20-30 minutes before it can be used.
Maintenance-free batteries: Due to their structural advantages, maintenance-free batteries consume very little electrolyte and generally do not require the addition of distilled water during their service life. They also feature shock resistance, high-temperature resistance, small size, and low self-discharge. Their lifespan is typically twice that of ordinary batteries. There are two types of maintenance-free batteries on the market: the first type requires only a single addition of electrolyte at the time of purchase and requires no further maintenance (addition of electrolyte); the second type is pre-filled with electrolyte and sealed at the factory, requiring no additional electrolyte from the user.
Dry-charged batteries, also known as dry-type lead-acid batteries, are characterized by their high energy storage capacity on the negative plates. In a completely dry state, they can retain the energy they have accumulated for up to two years. When in use, simply add electrolyte and wait 20 to 30 minutes before use.
Dry-charged battery symbol: In batteries, "A" indicates dry-charged.
For example, in the battery model number 6-QA-120D, the "A" indicates dry-charged.
Definition of dry-charged battery:
A dry-charged battery is one that is manufactured without electrolyte; electrolyte is added only when the battery is used. Its lifespan begins at this stage. Because no electrolyte is added before use, it is called a dry-charged battery. Except for maintenance-free batteries, most car batteries (passenger cars) are dry-charged.
Dry-charged batteries
Dry-charged batteries are batteries whose plates can retain their charge for a long time even when dry. The active material of the negative plate in this type of battery contains a certain proportion of antioxidants in the lead, such as rosin, lanolin, oleic acid, organic polymers, and fatty acids. After in-depth processing, the active material forms a deep, sponge-like structure. Following an anti-oxidation impregnation treatment, a very thin protective film adheres to the surface of the plates, improving their antioxidant performance. Finally, they undergo inert gas or vacuum drying treatment.
After this treatment, the spongy pure lead on the negative electrode plate remains in a dry state in the air for a long time without oxidation, and the large negative charge gained in the reaction does not disappear.
wet-charged batteries
The difference between wet-charged batteries and ordinary batteries is that they use plate groups for formation. After formation, the plates are immersed in a dilute sulfuric acid solution with a relative density of 1.35 (15℃) and containing 0.5% sodium sulfate (mass fraction). The sodium sulfate acts as an antioxidant on the surface of the active material of the negative plate. After centrifugation and acid leaching, they are assembled and sealed without drying. The plates and separators of wet-charged batteries still contain some electrolyte, and the inside of the battery is moist, hence the name "wet-charged battery".
3) Maintenance-free batteries
Maintenance-free batteries refer to batteries that require no maintenance other than keeping their surface clean during their service life. This is closely related to their structural characteristics.
A dry-charged battery does not mean it can be used in a vehicle without adding electrolyte. Rather, it refers to a battery that, after being filled with electrolyte of standard density, can be installed and used in a vehicle without initial charging. The structure of a dry-charged battery is the same as a regular lead-acid battery, but the difference lies in the special process used for its plates. For example, rosin, oleic acid, stearic acid, and other antioxidants are added to the lead paste of the negative plate. During plate formation, the formation time is appropriately extended, or a charge-discharge-recharge method is used to maximize the conversion of active materials. After formation, the negative plate is immersed in an antioxidant solution (a mixture of boric acid and salicylic acid) to form a protective film on the surface. Finally, the plates are dried in an inert gas atmosphere. Plates manufactured in this way can retain the charge obtained during manufacturing for a longer period under dry conditions. The "A" in dry-charged batteries, such as "6-QA-105," indicates that it is a dry-charged battery. Currently, ordinary lead-acid batteries used in domestic automobiles require 60-70 hours of initial charging before use, and sometimes even longer charge-discharge cycles. This necessary supplementary charging process severely impacts usability in emergency situations. In contrast, charged batteries only require adding sufficient electrolyte as specified and soaking for 20-30 minutes before installation and use, and they also have a longer lifespan.
The term "dry-charged battery" does not mean that it can be used in a vehicle without adding electrolyte. Rather, it refers to a battery that can be installed and used in a vehicle after adding electrolyte of the standard density without initial charging.
The structure of a dry-charged battery is the same as that of a regular lead-acid battery, but the difference lies in the special process used for its plates. For example, antioxidants such as rosin, oleic acid, and stearic acid are added to the lead paste of the negative plate. During plate formation, the formation time is appropriately extended, or a charge-discharge-recharge method is adopted to maximize the conversion of active materials. After formation, the negative plate is immersed in an antioxidant solution (a mixture of boric acid and salicylic acid) to form a protective film on the surface of the negative plate. Finally, the plate is dried in an inert gas atmosphere. Plates manufactured in this way can retain the charge obtained during the manufacturing process for a longer period of time under dry conditions.
The "A" in dry-charged batteries is used as a mark, such as "6-QA-105", indicating that it is a dry-charged battery.
Currently, ordinary lead-acid batteries used in domestic automobiles require 60-70 hours of initial charging before use, and sometimes even longer charge-discharge cycles. This necessary supplementary charging process severely impacts usability in emergency situations. In contrast, charged batteries only require adding sufficient electrolyte as specified and soaking for 20-30 minutes before installation and use, and they also have a longer lifespan.
