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SigmasTek  |  SKU: BW-4781

Best Power Unity UT3K UPS Compatible Replacement Battery Set

Sale price $331.28 USD Regular price $418.40
Shipping calculated at checkout.

➤ Includes 4 brand new SigmasTek SP12-35 NB batteries (12V 35AH)

➤ High rate discharge design for superior UPS performance

➤ Valve regulated, spill-proof construction for safety

➤ Low self-discharge ensures long shelf life

➤ U.L. recognized, CE certified, with 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 | 35 AH

Terminal Type

Nut & Bolt

Replacement Battery Set for Best Power Unity UT3K UPS

Upgrade your Best Power Unity UT3K Uninterruptible Power Supply with a reliable, high-performance replacement UPS battery set designed for compatibility, consistent performance, and dependable reliability. This complete set includes four SigmasTek SP12-35 NB batteries and is engineered for high rate discharge applications where brief, high power output is required. Whether you operate critical IT equipment, medical devices, or emergency power systems, these factory-fresh batteries deliver the power and peace of mind you expect from a long-lasting battery solution. Please note: you must reuse all existing cables and hardware from your original configuration to connect the new UPS batteries.

Key Specifications

  • Battery model: SigmasTek SP12-35 NB
  • Quantity: 4 batteries per set
  • Voltage: 12 Volts
  • Capacity: 35 AH
  • Terminal type: Nut & Bolt
  • Design: High Rate Discharge Design
  • Construction: Valve Regulated Spill Proof Construction
  • Self-discharge: Low Self-discharge
  • Durability: High Vibration Resistance
  • Certifications: U.L. Recognized and CE Certified
  • Condition: Brand New, Factory Fresh
  • Warranty: 1 Year Warranty
  • Compatible UPS model: Best Power Unity UT3K
  • Brand: SigmasTek

Benefits

  • Durability and Safety: The valve regulated spill proof construction and high vibration resistance make these batteries a durable choice for rack-mounted and tower UPS systems, reducing maintenance needs and increasing uptime.
  • Designed for Performance: The high rate discharge design supports short bursts of higher power output—ideal for protecting sensitive loads when utility power fails—making this a true high-performance UPS battery option for the Best Power Unity UT3K.
  • Reliable Long Life: Low self-discharge characteristics and quality-controlled manufacturing produce consistent capacity over time, delivering a long-lasting battery lifecyle that you can count on during critical events.
  • Certified Quality: U.L. recognition and CE certification demonstrate that these replacement UPS battery units meet stringent safety and performance standards commonly required in commercial and industrial environments.
  • Versatile Applications: Perfect for Uninterruptible Power Supply (UPS) units, emergency power supply systems, and battery-powered tools—these batteries are built for both everyday backup and demanding power events.
  • OEM-Level Fit and Performance: Our technically savvy staff tests each battery set to ensure it meets or exceeds OEM specifications for the Best Power Unity UT3K, giving you confidence in compatibility and performance.
  • Easy Ordering and Fast Shipping: In-stock orders typically ship within 24 hours so you can replace your UPS batteries quickly and restore full backup capacity without extended downtime.

If you’re ready to replace the batteries in your Best Power Unity UT3K, choose this trusted, high-quality SigmasTek SP12-35 NB set for dependable emergency runtime and performance. Buy this replacement UPS battery set today and secure a high-performance UPS battery and long-lasting battery solution for your critical equipment.



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