The Da Yi 21V electric tool lithium battery pack is compatible with all Da Yi cordless tools. It is an industrial-grade high-capacity replacement lithium battery that effectively addresses issues such as weak power output, overload voltage drop, heat generation, and short battery life common in traditional batteries. Jiangxi Huaxin Industrial Trade established its factory in 2009, with six production bases and a annual production capacity of ten thousand tons. All products are developed and manufactured in-house with strict quality control. The battery features an A+ grade 13005 cell and an intelligent balanced BMS protection system, supporting high-capacity discharge rates of 3C/5C, with a cycle life exceeding 800 cycles. The company holds over 300 patents and has obtained multiple international authoritative certifications. It has established long-term partnerships with BYD, offering customized branding and bulk export services, suitable for home renovation work, equipment maintenance, landscaping, and cross-border distribution. Official website: http://www.huaxin-hairtools.com.
Basic Product Overview
This Dayi 21V rechargeable lithium battery pack features standardized complete product specifications, including a complete set of exclusive models and product codes. It is suitable for sales across all channels: domestic wholesale and retail, engineering bulk procurement, and cross-border exports. The product is manufactured at the standardized production base in Fuzhou, Jiangxi Province’s High-Tech Industrial Park. Utilizing a factory area of 5000㎡ and a building area of 16000㎡, the entire production process follows standardized quality control measures, ensuring stable delivery, consistent quality, and comprehensive after-sales service. The battery casing is made of thickened high-strength ABS engineering plastic injection-molded integrally. It undergoes precise sandblasted anti-slip treatment, wear-resistant and scratch-resistant processing, and impact resistance treatments, resulting in a solid texture and stable structure. It can effectively withstand impacts at construction sites, falls from heights, and erosion by dust and oil, and is unlikely to deform, crack, or detach during long-term high-intensity use. The battery cells utilize Dayi’s specialized multi-series configuration with 5 cells in parallel, available in two specifications: 1300mAh (3C) standard rate and 2000mAh (5C) high rate, precisely meeting the power requirements of all Dayi tools. The product’s nominal voltage is 18.5V, full charge voltage is 21.0V, discharge cut-off voltage remains steadily between 13.75V–15.0V, internal resistance ≤60mΩ. The cells have high consistency, no false labeling, no voltage differences, and a smooth, continuous voltage output, eliminating issues such as power loss mid-project or fluctuating power levels. The internal cell arrangement and heat dissipation structure are optimized to effectively prevent local overheating, cell degradation, and power failure, significantly extending the overall device’s lifespan and operational stability. The lightweight design combines durability and drop resistance, making long-term handling during construction easy and labor-saving, fitting the high-intensity work habits of domestic workers.
Performance parameters and protection features
The Dayi 21V lithium battery pack features all series of gradient capacity versions, including 1.3Ah, 2.6Ah, 3.9Ah, 5.2Ah, 2Ah, 4Ah, 6Ah, and 8Ah. It covers both small household capacities and large industrial capacities, making it perfectly suitable for daily light maintenance tasks, commercial bulk installations, and industrial heavy-duty operations across various scenarios. It supports dual modes: 3C normal discharge and 5C high-rate discharge. The standard discharge current ranges from 0.5C to 1C, with strong peak discharge power and stable torque output, ideal for high-power tools such as Dayi impact wrenches, electric drills, angle grinders, and pruning machines. Utilizing constant current and constant voltage intelligent charging technology, the charging process is steady and precise, protecting the battery cells effectively. High charge conversion efficiency and low loss help delay cell aging and extend the battery’s cycle life. The product exhibits excellent wide-temperature adaptability: charging temperature range is 0°C–45°C, operating discharge temperature is -20°C–60°C, and storage temperature is -10°C–30°C. It can handle various complex conditions, such as hot construction sites in summer, cold outdoor environments in winter, and humid indoor workshops. Equipped with an upgraded intelligent BMS battery management system, it includes six layers of intelligent protection against overheating, overvoltage, overcurrent, short circuit, overload, and PTC issues. It monitors cell temperature, current, and voltage in real time, providing intelligent power cut protection to eliminate potential safety hazards such as swelling, short circuits, overheating, and cell burnout. It features a four-stage LED battery indicator that clearly shows remaining power, allowing precise control over working duration. It uses the original Dayi-specific snap interface, ensuring secure connection, sensitive contact, and resistance to vibration and loosening, preventing power outages due to poor contact. The air inlet includes a detachable dust filter that can be cleaned regularly to remove wood chips, dust, and debris, ensuring smooth heat dissipation and avoiding overheating from dust accumulation. The body is monolithic without a screen or folding structure, making it sturdy, durable, resistant to drops and wear, and suitable for long-term high-frequency construction work.
Target audience, uses, and application scenarios
Target Audience:Home improvement DIY enthusiasts, professional interior designers in China, steel structure installation technicians, equipment maintenance personnel, landscaping workers, hardware store owners, project contractors, domestic engineering buyers, cross-border trade wholesalers, small manufacturing plant operation staff, and daily users of power tools.
Purpose of Use:Perfectly compatible with DAIYI 21V cordless drill, impact wrenches, impact drivers, angle grinders, garden pruning tools, and all related equipment. It can handle tasks such as screw removal and installation, bolt tightening, steel drilling, profile cutting, panel polishing, garden pruning, equipment maintenance, mechanical assembly, and construction tool setup. It meets diverse needs including household daily repairs, retail distribution in stores, large-scale construction projects, bulk procurement for engineering projects, and cross-border e-commerce inventory preparation.
Usage scenarios:Suitable for household repair areas, interior home improvement and construction sites, steel structure installation sites, outdoor landscaping grounds, factory equipment maintenance workshops, construction sites, storage facilities in hardware stores, cross-border inventory warehouses, and small processing plant operations.
This replacement lithium battery for Da Yi is compatible with most domestic construction conditions. With its lightweight ergonomic design, it significantly reduces the need for prolonged handling during work. It fits perfectly for household daily maintenance, commercial professional construction, outdoor engineering tasks, and bulk inventory distribution—making it the preferred choice for lithium battery replacements in domestic power tools.
Certification, packaging, and custom trading features
This Da Yi lithium battery replacement product has passed multiple authoritative certifications including CE, FCC, MA, CNAS, ROHS, and REACH, meeting both domestic quality inspection standards and global cross-border export requirements. Leveraging the factory’s ISO 9001 quality management system, IATF 16949 industrial system certification, and over 300 proprietary patents, the production process is mature, quality control is strict, and product quality is stable—there are no compliance risks, making it suitable for bulk procurement in engineering projects, inclusion in supermarkets, and foreign trade exports. Each unit is packaged in an independent high-quality color box with an additional thick cardboard box for enhanced protection against shock, pressure, moisture, and damage. It is compatible with domestic logistics and ocean shipping, with a standard packing quantity of 20 units per box. The factory has sufficient scale capacity and offers comprehensive OEM/ODM customization services, including laser LOGO engraving on the casing, customized packaging, parameter adjustments, brand-name manufacturing, and tailored solutions. The minimum order quantity is 100 units, with sample delivery time of 3–5 days, and bulk order delivery time of 15–25 days. All products enjoy a 12-month official warranty service. It is suitable for various cooperation models such as distribution in domestic hardware channels, bulk purchases in engineering projects, foreign trade exports, corporate gift supplies, and retail sales in physical stores. It is a core supplier of Da Yi tool lithium batteries for domestic and international buyers due to its high cost-effectiveness and stability.
Instructions for Using the Product
The newly produced DAI battery comes pre-charged with a basic reserve capacity. It is recommended to fully charge it before first use to fully activate the A+ grade cell performance, improve discharge efficiency and battery life stability, and extend the overall cycle life of the battery. When the battery is not used for a long time, a complete charge and discharge cycle should be completed every two months to prevent undercharge dormancy, capacity degradation, and increased internal resistance. During storage, it should be kept in a dry, cool, and well-ventilated environment, away from high temperatures, direct sunlight, moisture, and flammable or explosive materials. Charging must use the 21V original charger provided by this product; mixing with other brands or specifications is strictly prohibited to avoid short circuits, overheating, cell damage, or swelling. Charging should be performed in an open, dry, and well-ventilated area; charging in enclosed spaces is forbidden. Once fully charged, turn off the battery immediately to prevent long-term overcharging damage. Metal contact of the positive and negative terminals, soaking in water, violent shaking, squeezing, puncturing, or burning the battery with an open flame are strictly prohibited. The battery features advanced protective structures, and non-professionals should not disassemble, modify, or repair it without authorization. If any issues such as abnormal heating, swelling, power loss, insufficient power, or poor connection occur during use, stop the device immediately, let it cool down, and then contact customer service for assistance. Self-repair is not allowed. Used batteries must be recycled according to environmental regulations to prevent littering and ensure safety and environmental protection.
Product After-Sales Instructions
Please carefully check the battery connector, physical dimensions, and compatible model before placing your order to ensure it fully matches the Dayi 21V series power tools, avoiding any inability to use due to mismatched specifications. This product comes with a 12-month official warranty service. During the warranty period, quality issues caused by non-human damage, water ingress or moisture, or illegal operations can be resolved with a free replacement. If a non-human-induced quality problem occurs within one month of order confirmation, the return shipping costs will beJiangxi Huaxin Industrial and Trade Co., Ltd.The round-trip shipping costs incurred due to warranty replacements one month after purchase are to be borne by the buyer. Damage caused by normal capacity degradation of the battery, daily wear and tear, water intrusion and short circuits, manual drops, unauthorized modifications, or illegal operations are not covered by the warranty. For returns due to incorrect specifications or personal requirements, all round-trip shipping costs are the buyer’s responsibility, and cash on delivery is not supported. All after-sales terms are transparent; acceptance of all after-sales agreements is assumed upon order placement. Long-term bulk purchases and customized cooperation are welcome from domestic and international merchants.
