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SigmasTek  |  SKU: BW-4271

APC BACKUPS BK420S UPS High Performance Replacement Battery

Sale price $16.99 USD Regular price $24.15
Shipping calculated at checkout.

➤ AGM technology delivers long-lasting, reliable power

➤ High rate discharge supports emergency and tool use

➤ Maintenance-free with spill-proof construction

➤ U.L. recognized and CE certified for safety compliance

➤ Fits APC BACKUPS BK420S model, includes 1-year warranty


📦🚀 FAST SHIPPING: Usually ships same day if ordered before 2 PM EST

⚠️ Quick Reminder

🔹 Please ensure the original battery model number is listed in our product description and that your device model number matches for compatibility.
🔹 We only supply the batteries shown in the images. Device images are provided for reference only.

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Battery Care Guide

Battery Usage and Maintenance Guidelines 🔋

Please read the following instructions carefully before using your new battery. Proper adherence will help ensure optimal performance and extended service life.

1. Cordless Phones, PDAs, and Power Tools (NiMH, NiCd, Lithium-Ion) 📱

Initial Charge

  • Fully charge the battery overnight prior to first use.

Conditioning (First 2–6 Charge Cycles)

  • Operate the device until the battery reaches approximately 20% capacity.
  • Avoid premature recharging.
  • Do not allow the battery to fully discharge during the initial cycles.

Post-Conditioning

  • Recharge the battery only when necessary.
  • These batteries are capable of approximately 500 charge cycles:
  • Once daily → ~500 days
    Twice daily → ~250 days
    Note: Even a partial recharge is considered a full cycle.

2. Sealed Lead Acid (SLA) Batteries 💡

  • No conditioning required.
  • Maintain the battery in a fully charged state; avoid complete discharge.
  • Capable of 300–400 charge cycles.
  • Expected service life: 2–3 years, depending on usage conditions.

3. Laptop Batteries (Lithium-Ion) 💻

Initial Charge

  • Fully charge the battery overnight prior to first use.

Conditioning (First 2–6 Charge Cycles)

  • Charge fully, then discharge to approximately 20% capacity.
  • Avoid complete discharge, as some devices may not detect a fully drained battery.

Post-Conditioning

  • Minimize frequent plugging and unplugging.
  • Allow the battery to discharge moderately at least once per month to maintain optimal performance.
  • Occasional cycling is recommended to sustain battery health.

Professional Recommendation

Adhering to these guidelines will enhance battery longevity and ensure reliable performance.

For further assistance regarding your battery or order, our customer support team is available to provide guidance.

Delivery and Shipping

Everything You Need to Know About Shipping with BatteryWeb (USA)

We know reliable delivery matters when you need power fast. Here’s how BatteryWeb makes shipping easy across the USA:

🚚 Shipping & Delivery

Most orders ship next business day (some products like sealed lead acid may take a little longer).

Same-day shipping available if you order before 11:59 AM (delivery depends on the carrier).

We ship nationwide using FedEx, UPS, USPS, DHL, and regional ground carriers.

Shipping costs are calculated automatically at checkout based on weight, distance, and carrier.

Transit times shown are estimates only (business days, no weekends/holidays).

🌍 Shipping Restrictions

Lithium batteries cannot be shipped by USPS or air. They must go via FedEx Ground, UPS Ground, or DHL Ground.

PO Box deliveries are only available via USPS.

At this time, we do not ship lithium batteries to Puerto Rico. NiMH, NiCd, and Alkaline can be shipped.

📦 Important Notes

Double-check your shipping address! If an incorrect address is used and the order is returned, re-shipping costs are the buyer’s responsibility.

If a product is temporarily out of stock, we’ll notify you right away with the expected restock date—or issue a refund if you prefer.

💲 Currency & Pricing

All prices are shown in USD.

Orders shipped outside the USA may be subject to local taxes, customs fees, or import duties. These are the buyer’s responsibility.

⚡ At BatteryWeb, we’re committed to getting your batteries delivered quickly, safely, and affordably—so you’ll always have the power you need, when you need it.

Disclaimer

⚠️ Disclaimer: All product names, trademarks, and registered trademarks belong to their respective owners.

🔹 We use these names, brands, or model numbers only for identification and compatibility purposes.

🔹 Our products are generic replacement parts and are not affiliated with, endorsed by, or manufactured by the original equipment manufacturers (OEMs).


Volts & Amps

12 Volts | 7.5 Ah

Terminal Type

F2

Replacement APC BACKUPS BK420S Battery — Compatible with APC BACKUPS BK420S

Designed for perfect compatibility with the APC BACKUPS BK420S, this replacement UPS battery delivers reliable performance, dependable emergency power, and maintenance-free operation when you need it most. Whether you are restoring backup power to a home office UPS or replacing an old SLA cell, this high-performance UPS battery meets or exceeds OEM specifications and offers the dependable uptime your APC BACKUPS BK420S requires. Built with quality materials and certified safety features, it’s an ideal long-lasting battery solution for anyone seeking a cost-effective, compatible replacement.

Key Specifications

  • Compatible Model: APC BACKUPS BK420S
  • Battery Type: Sealed Lead Acid (SLA)
  • Technology: Absorbent Glass Mat (AGM) Technology
  • Design: High Rate Discharge Design
  • Maintenance: Maintenance-Free Design with Spill Proof Construction
  • Safety Certifications: U.L. Recognized and CE Certified
  • Condition: Brand New, Factory Fresh
  • Warranty: 1 Year Warranty
  • Brand: SigmasTek
  • Voltage: 12 Volts
  • Capacity: 7.5 Ah
  • Terminal Type: F2
  • Primary Applications: Emergency Power Supply, Battery Powered Tools

Benefits

This replacement UPS battery is engineered for durability and long life. The Absorbent Glass Mat (AGM) construction provides a sealed, leak-proof design that resists vibration and minimizes maintenance — ensuring your UPS remains ready without frequent service. The high rate discharge design supports rapid delivery of power during outages, making this a high-performance UPS battery choice for critical devices and sensitive electronics.

As a maintenance-free and spill-proof unit, it reduces downtime and simplifies replacement tasks. The U.L. recognition and CE certification confirm that the battery meets important safety and quality standards. Backed by a 1 Year Warranty and shipped brand new and factory fresh, this long-lasting battery offers peace of mind for both home and small business environments.

Typical uses include UPS backup for home and office systems, emergency power supply for networking equipment, and powering battery-operated tools where a robust SLA is required. Its 12 Volts, 7.5 Ah capacity and F2 terminal make it a direct fit for APC BACKUPS BK420S units, ensuring quick installation and reliable operation.

Ready to restore dependable backup power? Order this replacement UPS battery for your APC BACKUPS BK420S now and enjoy a high-performance, long-lasting battery replacement backed by safety certifications and a 1 Year Warranty.


Payment & Security

Payment methods

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