FirstPower FP645K Compatible Replacement Battery
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⚠️ 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 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
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
⚠️ 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
6 Volts | 4.5 AH
Terminal Type
F1
FirstPower FP645K Replacement Battery — Compatible with FirstPower FP645K
Replace your original battery with a reliable, factory-fresh FirstPower FP645K replacement battery engineered to meet or exceed OEM specifications. This high-performance replacement battery provides the compatibility, consistency, and long-term reliability you need for backup power and everyday applications. With AGM technology and a maintenance-free design, the FP645K replacement is built to perform in demanding environments while remaining safe and easy to use.
Key Specifications
- Model Compatibility: FirstPower FP645K
- Brand: SigmasTek
- Voltage: 6 Volts
- Capacity: 4.5 AH
- Technology: Absorbent Glass Mat (AGM) Technology
- Design: Maintenance-Free with Spill Proof Construction
- Certifications: U.L. Recognized and CE Certified
- Condition: Brand New, Factory Fresh
- Warranty: 1 Year Warranty
Benefits
This replacement battery is designed for longevity and dependable operation. AGM construction enhances charge acceptance and resistance to vibration, contributing to a long-lasting battery life and reliable performance under repeated cycling. The maintenance-free design and spill-proof housing minimize upkeep and provide safe operation for indoor and portable applications. As a high-performance battery, the FP645K replacement maintains consistent power delivery for sensitive equipment and critical backup tasks.
Common uses include UPS backup systems, emergency lighting, alarm and security equipment, medical devices, and small portable tools—wherever a dependable 6V supply is required. Safety certifications like U.L. Recognition and CE conformity ensure this unit meets quality and safety expectations. Being brand new and factory fresh with a 1 year warranty, the battery offers value and peace of mind over cheaper, uncertified alternatives.
If you need a replacement battery that balances affordability with reliable performance for your FirstPower FP645K, this unit is an ideal match. It provides consistent output, fast recovery after discharge, and dependable support for essential systems.
Ready to replace your worn battery? Purchase this FirstPower FP645K replacement battery now and secure reliable, long-lasting power for your equipment.
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