Insignia Flex NS Replacement Battery 3.7V 4000mAh
Check that your old battery model number and device model to match our description. This makes sure they work together.
We ship your order same day if you buy it before 4 PM EST.
Insignia Flex NS Replacement Battery 3.7V 4000mAh - is backordered and will ship as soon as it is back in stock.
Let customers speak for us
Send Your Battery Photo
Expert Technician Help
Snap a photo or video of your battery and send it to us. We'll identify the exact replacement—fast and hassle-free. Our team has helped thousands of customers find the right battery quickly and easily.
POST YOUR BATTERY IMAGE
Product & Solutions Expert
✉ sales@batteryweb.com
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.
Insignia Flex NS Replacement Battery 3.7V 4000mAh - is backordered and will ship as soon as it is back in stock.
Voltage
3.7V
Amp
4000mAh
Insignia Flex NS / P08A7100 — 3.7V Li-Polymer Replacement Battery (PR-3797103)
This is a 3.7V, 4000mAh lithium-polymer cell matching OEM part number PR-3797103. It fits the Insignia Flex NS and P08A7100 tablets. Install it when the original cell no longer holds a useful charge or the tablet shuts down unexpectedly under load.
- Flex NS and P08A7100 compatibility: Both models share the same battery bay dimensions, connector pinout, and charge IC handshake. The PR-3797103 footprint — 105.90 × 99.40 × 3.50mm — is consistent across both board revisions, so one part number covers both.
- Bench tested on actual hardware: We ran the battery through a full charge cycle on a Flex NS unit and monitored BMS communication. The charge IC accepted the cell without fault codes, and protection thresholds — overcurrent, overvoltage, and temperature cutoff — all triggered at expected values.
- Fuel gauge recalibration after swap: After fitting this battery, run the tablet down to automatic shutoff, then charge it uninterrupted to 100%. This forces the fuel gauge IC to calibrate against the new cell's actual capacity curve and clears the inaccurate percentage readings that almost always appear right after a swap.
Why the Flex NS shuts down at 15–25% after a battery replacement
The Flex NS fuel gauge IC stores a learned discharge curve from the old cell. When a new cell goes in, that stored curve no longer matches actual voltage behaviour. The tablet sees the new cell's voltage drop at the low end and interprets it as a critical shutdown threshold, even though real capacity remains. One full discharge-to-shutoff cycle followed by an uninterrupted charge to 100% resets the learned curve. After that cycle, shutdowns at inflated percentages stop.
Fast charging unavailable on the Flex NS after a battery swap
The Flex NS charge controller negotiates charge rate partly based on cycle data it associates with the installed cell. Immediately after a swap, the controller defaults to a conservative charge rate until it completes one accepted full cycle. This is not a fault with the replacement battery. Plug the tablet in with the manufacturer's charger and let it complete one full charge to 100% without interruption — fast charge capability restores after that first accepted cycle.
Compatible Models
Replaces Part Numbers
Technical Specifications
Product Highlights
- Brand: Insignia
- Manufacturer: CS
- Series: Standard
- Color: Black
- Product Type: Li-Polymer
- Battery Type: Li-Polymer
- Warranty: 12 Months
- Bulk Orders: sales@batteryweb.com
Frequently Asked Questions
My Insignia Flex NS is reporting 80% battery but shuts itself off — why?
The fuel gauge IC on the Flex NS calibrated its discharge curve to the old cell. With a new battery installed, the voltage profile at the low end looks different, so the IC triggers a shutdown early. Run the tablet down to automatic shutoff, then charge uninterrupted to 100%. That single full cycle resets the calibration and the percentage readings will track correctly from that point.
The Flex NS percentage drops from 100% to the mid-70s within the first few minutes of use — is the battery faulty?
This is fuel gauge drift, not a cell fault. The IC's stored capacity map still reflects the worn-out original battery, so it reads a new, full cell as partially depleted once load hits. Complete one full discharge cycle — run to automatic shutoff, then charge to 100% without interruption. The percentage will stabilise after the gauge IC maps the new cell's actual capacity.
The Flex NS feels warm near the charging port while charging the new battery — is that normal?
Warmth during the first charge cycle is expected. The charge IC on the tablet runs a conditioning pass on a new cell, which draws slightly higher current than a routine top-up charge. Surface temperature at the back of the tablet rising modestly is normal charge IC behaviour. If the tablet becomes hot to the touch or the screen dims unexpectedly mid-charge, disconnect and check that the charger voltage matches the original — it should be 5V.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
Related Products
Engineered for Performance. Built to Last.
Check out our top-rated selection of reliable products built to last. We offer high-quality options that deliver consistent performance for all your needs.
-
Up to 21% offNew arrival
BatteryWeb
Amazon Kindle Paperwhite 4 ST22 Replacement Battery 3.8V 1500mAh
0.12 lb
Sale priceFrom $30.99 USD Regular price $38.99Unit priceIn stock (156 units) -
-
Up to 19% offNew arrival
BatteryWeb
Samsung Galaxy Book 12.0 Replacement Battery EB-BW720ABA 7.7V
0.68 lb
Sale priceFrom $70.99 USD Regular price $87.99Unit priceIn stock (33 units) -
-
Up to 20% offNew arrival
BatteryWeb
Samsung Galaxy Tab A SM-T510 EB-BT515ABU Replacement Battery 3.85V 6000mAh
0.51 lb
Sale priceFrom $37.99 USD Regular price $46.99Unit priceIn stock (183 units) -
-
Up to 20% offNew arrival
BatteryWeb
DigiLand Quad Core 8" Replacement Battery 3.7V 4000mAh
0.48 lb
Sale priceFrom $34.99 USD Regular price $43.99Unit priceIn stock (72 units) -
-
Up to 21% offNew arrival
BatteryWeb
Lenovo Tab V7 Replacement Battery L18D1P33 3.85V 5050mAh
0.23 lb
Sale priceFrom $30.99 USD Regular price $38.99Unit priceIn stock (63 units) -
-
Up to 20% offNew arrival
BatteryWeb
Lenovo Tab E7 TB-7104F Replacement Battery 3.85V 2650mAh
0.14 lb
Sale priceFrom $27.99 USD Regular price $34.99Unit priceIn stock (54 units) -
-
Up to 20% offNew arrival
BatteryWeb
Asus ZenPad 3S 10 LTE Replacement Battery C12P1602 3.85V
0.54 lb
Sale priceFrom $39.99 USD Regular price $49.99Unit priceIn stock (84 units) -
-
Up to 19% offNew arrival
BatteryWeb
Lenovo Smart Tab M10 Replacement Battery L18D1P32 3.85V
0.46 lb
Sale priceFrom $33.99 USD Regular price $41.99Unit priceIn stock (39 units) -
