ZTHY 266J9 Replacement Battery for Dell G3 G5 Inspiron

The ZTHY 266J9 is a direct-replacement 11.4V, 51Wh (3‑cell) Li‑Polymer battery designed to match specified Dell G3, G5 and Inspiron laptop models and their listed part numbers.

If your Dell laptop shows reduced run time or a failing battery message, this ZTHY OEM‑style pack offers the same voltage and form factor as the original 266J9 series cells so you can restore portable power. It’s built to fit models like the Dell G3 15 (3500, 3590), G5 15 (5500, 5505), and several Inspiron 14/15 series referenced in the compatibility list. Read the specifications and installation notes below to confirm you’re choosing the correct 3‑cell option rather than the alternate 4‑cell model.

How do I confirm this battery fits my Dell laptop?

Check the part number printed on your original battery and compare it with the replacement numbers listed for the ZTHY 266J9. Pay attention to capacity and cell count; this listing is for the 51Wh (3‑cell) variant, not the 68Wh (4‑cell) alternative used in some G3/G5 models.

• Match printed part numbers: 266J9, 0415CG, C9VNH, 0PN1VN, 0M4GWP.
• Verify battery capacity: 51Wh / 4255mAh and cell count: 3‑cell.
• Compare physical shape and connector location with your original battery.
• Reference your laptop model (e.g., G3 3500/3590, G5 5500/5505, Inspiron 5490).

What are the key specifications and safety features?

This ZTHY replacement uses Li‑Polymer cells at 11.4 volts and 51Wh capacity, supplied new by the manufacturer and rated for typical multi‑hundred cycle life. The product follows recognized safety standards and includes certifications for safer operation during normal use.

• Battery type: Li‑Polymer, voltage: 11.4V, capacity: 51Wh / 4255mAh (3‑cell).
• Manufacturer new unit; designed for roughly up to 500 recharge cycles.
• Safety certifications: CE and UL compliance noted for electrical and environmental standards.
• Pack color and finish: black housing consistent with factory replacements.

How should I install and initialize the new battery?

Install the battery only after powering down and removing the original pack following your laptop’s service instructions. If the system does not immediately recognize the new battery, recheck the connector seating and perform a charge/discharge cycle to help the battery reporting settle.

• Power off and disconnect AC before swapping batteries; follow Dell service guidance.
• If not recognized, reseat the connector and ensure firm contact.
• To calibrate: discharge to about 10–20% (avoid full 0%), then fully charge; repeat 3–4 times if needed.
• Refer to BIOS and battery health tools for updated status after installation.

Who is this replacement battery for? If you own a Dell G3 15, G5 15, or listed Inspiron series that originally shipped with the 266J9/51Wh battery and you want a like‑for‑like 3‑cell swap, the ZTHY 266J9 pack provides the compatible voltage and dimensions for a direct replacement. Choose this item when part numbers match, you prefer a new manufacturer unit with CE/UL safety compliance, and you understand the difference between the 3‑cell 51Wh and the 4‑cell 68Wh options for certain model variants. If you are unsure, compare your existing battery label to the replace part numbers above before purchase or contact support for verification.