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SigmasTek  |  SKU: BW-3781

Deltec RS21 UPS High Performance Replacement Battery Set

Sale price $149.10 USD Regular price $188.32
Shipping calculated at checkout.

➤ Includes 10 SigmasTek SP12-7.5HR batteries (12V 7.5AH) for Deltec RS21 UPS

➤ High rate discharge design for superior short-term power output

➤ Valve regulated, spill-proof, and vibration resistant construction

➤ Brand new, factory fresh with 1-year warranty and certified safety standards

➤ Compatible with original cables and hardware for easy installation


📦🚀 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

SigmasTek SP12-7.5HR Replacement Battery Set for Deltec RS21 UPS

Restore reliable runtime to your Deltec RS21 with this brand new replacement UPS battery set engineered for performance, safety, and consistent power delivery. Designed to meet or exceed OEM expectations, these SigmasTek SP12-7.5HR batteries deliver dependable support for high-rate discharge scenarios and short-duration, high-power demands. If you need a replacement UPS battery that balances immediate output and long-term reliability for your Deltec RS21, this kit is an excellent choice.

Key Specifications

  • Battery model: SigmasTek SP12-7.5HR
  • Voltage: 12 Volts
  • Capacity: 7.5 AH
  • Quantity: 10 batteries included
  • Terminal type: F2
  • Design: High Rate Discharge Design
  • Construction: Valve Regulated Spill Proof Construction
  • Self-discharge: Low Self-discharge
  • Vibration resistance: High Vibration Resistance
  • Certifications: U.L. Recognized and CE Certified
  • Condition: Brand New, Factory Fresh
  • Warranty: 1 Year Warranty
  • Compatibility note: Use all existing cables and hardware from original configuration to connect new UPS batteries

Benefits

These replacement UPS battery modules are built for durability and consistent performance. The high rate discharge design provides the power needed for brief but demanding loads, making this a high-performance UPS battery solution ideal for protecting critical equipment. Valve regulated, spill proof construction and low self-discharge characteristics extend shelf life and reduce maintenance concerns, while high vibration resistance helps ensure stable operation in rack or portable installations.

You’ll get a long-lasting battery option that is brand new and factory tested to meet or exceed OEM specs for the Deltec RS21. The U.L. recognition and CE certification reflect industry-standard safety and quality checks, so you can install with confidence. This set is particularly well suited to Uninterruptible Power Supply (UPS) units, emergency power supply systems, and battery powered tools that require reliable short-term, high-current support. Whether replacing end-of-life cells or building a serviceable spare, these batteries are optimized for practical field use and quick replacement.

For installation: please note you must reuse all original cables and mounting hardware from your Deltec RS21 to connect these replacement batteries. Our technically savvy staff personally tests each battery set, guaranteeing consistent performance and compatibility.

Buy this replacement UPS battery set for your Deltec RS21 now to regain reliable runtime and protect your equipment with a high-performance, long-lasting battery solution. Order today and take advantage of fast shipping and a 1 year warranty.



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