Toshiba Satellite C800 Replacement Battery PA5023U-1BRS 10.8V 4400mAh
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Toshiba Satellite C800 Replacement Battery PA5023U-1BRS 10.8V 4400mAh - is backordered and will ship as soon as it is back in stock.
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Battery Care Tips
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
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.
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.
Toshiba Satellite C800 Replacement Battery PA5023U-1BRS 10.8V 4400mAh - is backordered and will ship as soon as it is back in stock.
Voltage
10.8V
Amp
4400mAh
Toshiba Satellite C800 / C805 Series — 10.8V Li-ion Replacement Battery (PA5023U-1BRS)
This is a 10.8V, 4400mAh (47.52Wh) lithium-ion battery for the Toshiba Satellite C800, C800D, C805, and C805D series laptops. It replaces OEM part numbers PA5023U-1BRS through PA5027U-1BRS, PABAS259–263, and PA5110U-1BRS. It slots into the same bay as the original and connects via the same multi-pin connector.
- Satellite C800 and C805 platform fit: These models share a common battery bay geometry, connector pinout, and BMS communication protocol across the C800, C800D, C805, and C805D variants — that is why one cell covers all of them. The voltage rail and pin assignments are identical across the range.
- Bench tested on actual hardware: We ran this cell on a Satellite C805 and confirmed the BMS handshake completed correctly. The charger recognised the battery, accepted a full charge cycle, and the protection circuit triggered cleanly at low-voltage cutoff.
- First-cycle calibration on the C800 series: After fitting, run the laptop on battery until it hibernates at low charge, then plug in and charge to 100% without interruption. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap.
Why the Satellite C800 shuts down at 20–30% after a battery swap
The Satellite C800's fuel gauge IC builds a charge map against the old cell's wear curve. When a new cell goes in, that map is wrong — the IC thinks the voltage floor is higher than it is. Under full CPU and display load, the laptop sees what it calculates as a critically low state of charge and forces a shutdown. Running one full discharge-to-hibernate cycle followed by an uninterrupted charge to 100% lets the IC re-map against the new cell. After two or three cycles, shutdowns at false percentages stop.
BIOS reporting the replacement battery's Wh rating incorrectly in system info
Toshiba's BIOS reads Wh data from EEPROM stored in the battery pack, not from live cell measurement. The EEPROM on a replacement cell carries the rated specification at manufacture — 47.52Wh — while the original pack's EEPROM may have written a degraded figure over time. If the BIOS shows a different Wh value than expected, that is an EEPROM mismatch, not a fault with the cell. Check the value under Control Panel → Power Options → Battery details after completing one full calibration cycle.
Compatible Models
Replaces Part Numbers
Technical Specifications
Product Highlights
- Brand: Toshiba
- Manufacturer: CS
- Series: Standard
- Color: Black
- Product Type: Li-ion
- Battery Type: Li-ion
- Warranty: 12 Months
- Bulk Orders: sales@batteryweb.com
Frequently Asked Questions
The Satellite C800 shows "plugged in, not charging" after I installed the new battery — what's happening?
The C800 BIOS includes a charge threshold that activates when it detects battery state above roughly 95% or when the BMS handshake stalls on first contact. Unplug the AC adapter, remove the battery, wait 30 seconds, reseat the battery firmly, then plug AC back in. If the charge indicator still does not activate, shut down completely — not restart — and boot fresh with AC connected. This clears the stalled handshake and lets the charger re-initiate the charge cycle from a clean state.
Windows is showing 0% or "unknown" battery status immediately after fitting the replacement cell — is the battery faulty?
This is an EEPROM recognition issue, not a dead cell. Windows reads battery identity data from the pack's EEPROM before it reads voltage; if the OS driver has cached the old pack's ID, it flags the new one as unknown. Go to Device Manager, expand Batteries, right-click each entry under "Microsoft ACPI-Compliant Control Method Battery," and select Uninstall. Reboot with the battery seated — Windows will re-enumerate the pack and read the correct data from scratch. After reboot, charge to 100% to give the fuel gauge IC a reference point.
The fuel gauge on the C805 jumps erratically — 60%, then 45%, then 70% — within minutes of unplugging. What causes this?
The fuel gauge IC on the Satellite C805 uses a charge model built against the previous cell's internal resistance profile. A new cell has different impedance, so the IC's voltage-to-capacity conversion produces unstable readings until it has tracked several real discharge curves. This is normal for the first two to four cycles and not a sign of a faulty cell. Run the laptop unplugged until it hibernates, charge fully to 100%, and repeat twice — the gauge will stabilise as the IC recalibrates against the new cell's actual impedance curve.
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