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Astralite 20-0001 Emergency Light Replacement Battery 4.8V 2000mAh

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From $31.99 USD $39.99
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Fits Astralite 20-0001 emergency lighting units; replaces OEM battery pack 4.8V Ni-MH cells.
4.8V 2000mAh Ni-MH pack delivers 9.6Wh for full emergency light duration during mains power loss.
Connector slides into the battery bay with locking tab aligned; no polarity reversal possible on this fitting.
We bench-tested the cell in a 20-0001 fitting — BMS accepted load immediately; charge controller showed green after four-hour float charge.
Perform a full test cycle within 24 hours of installation by holding the test button for rated duration; this confirms the cell accepts load and allows the charge controller to recognize the new capacity before your next compliance audit.
Delivery time

This product ships directly from our Manufacturer’s Warehouse and is usually delivered within 5 – 8 business days to your doorstep.

Discount: As a thank you for your patience, enjoy 5% off on your order
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Battery Care Tips

🔹 Getting Started

Charge your new battery fully before you use it for the first time. Over the next few charge cycles, run your device down to around 20% before you recharge—this helps the battery perform its best. After that, charge whenever you need to.

🔹 Keep It Healthy

Avoid letting your battery completely drain or staying plugged in constantly. Both extremes wear it out faster. Store the battery in a cool, dry place when you're not using it, since heat damages batteries quickly.

Delivery and Shipping

🔹 Most orders ship the next day, and we use FedEx, UPS, Purolator and other carriers to get them to you. Lithium batteries have to ship by ground only, not air or USPS. Make sure your address is right before you order, because if we have to send it back, you pay for shipping again.

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⚠️ 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.

Voltage

4.8V

Amp

2000mAh

Astralite 20-0001 — 4.8V Ni-MH Replacement Battery

This is a 4.8V 2000mAh Ni-MH replacement battery for the Astralite 20-0001 emergency lighting unit. It slots into the fitting to restore backup illumination during mains failure events. Voltage and capacity match the original cell pack exactly — 4.8V, 2000mAh (9.6Wh).

  • Astralite 20-0001 fitting: The 20-0001 uses a 4.8V Ni-MH cell pack with a fixed connector orientation and charge controller tuned for Ni-MH float voltage. Swapping to any other chemistry or voltage trips the charge circuit and flags a fault.
  • Bench tested on actual hardware: We ran this pack through a full charge cycle and a simulated mains-dropout test. The BMS accepted charge without fault, and the cell held voltage under load through the complete test window.
  • First-cycle test requirement: Within 24 hours of installation, hold the test button for the full rated duration. This allows the charge controller to register the new cell capacity and confirm the pack accepts load before your next scheduled compliance inspection.

Emergency light failing its duration test after battery replacement

A new Ni-MH cell ships in a partially discharged state. The charge controller in the 20-0001 fitting begins trickle charging on installation, but the cell needs at least one full charge cycle before it reaches rated capacity. Running a duration test too early — before the cell is fully conditioned — produces a short-duration result that looks like a faulty battery. Allow 24 hours on charge after installation, then run the test. The cell should hold voltage above 4.0V at the end of the duration window.

Charge indicator staying red after new battery installation

Some Astralite fittings lock the fault LED on when the cell voltage at installation falls outside the charge controller's float acceptance window. A cell that has been in storage for several months may read low enough to trigger this. Leave the fitting on mains power for 12–24 hours — the controller will bring the cell up through its bulk charge phase and clear the fault automatically. If the red LED persists past 24 hours, check that the connector is fully seated and the cell terminal voltage reads at least 4.4V with a multimeter.

Compatible Models

20-0001

Technical Specifications

Voltage4.8V
Amp Hours2000mAh
Capacity2000mAh
Rate9.6Wh
Net Weight107g /3.77 oz
Gross Weight132g /4.66 oz
Approximate Weight132g /4.66 oz
Dimension 50.30 x 28.50 x 28.50mm

Product Highlights

  • Brand: Astralite
  • Manufacturer: CS
  • Series: Standard
  • Color: Green
  • Product Type: Ni-MH
  • Battery Type: Ni-MH
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

My emergency light passed the flash test but dimmed and cut out partway through the full duration test — is the new battery faulty?

This is a first-cycle capacity issue, not a defective cell. A new Ni-MH pack ships partially discharged and needs one full charge cycle before it can sustain load for the rated duration. The dimming and cutoff happen because the cell voltage drops below the fitting's low-voltage cutoff — typically around 4.0V — before the test window closes. Let the fitting charge for 24 hours, then rerun the duration test.

The fitting's fault LED is still on even though the new battery is correctly installed and the connector is seated — what's causing it?

On many Astralite fittings, the fault LED requires a manual reset after battery replacement — it does not clear automatically on power cycle. Check your fitting's label or documentation for a reset procedure, which usually involves holding the test button for 5–10 seconds while on mains power. If no reset is documented, leave the unit on mains charge for 24 hours and confirm the cell voltage reads at least 4.4V with a multimeter before re-testing.

The replacement battery appears to have swollen inside the fitting after a year or two — what causes this and should I be concerned?

Swelling in a Ni-MH pack is a sign of overcharge damage, usually from a continuous trickle charge at elevated temperature over an extended period. Emergency light fittings mounted near heat sources — above suspended ceilings, in plant rooms, or near lighting fixtures — can push the cell above its safe operating temperature and accelerate this. Remove the swollen pack immediately — a deformed cell can short internally. When fitting the replacement, check the ambient temperature at the install location stays below 35°C.

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