COWIN E7 Replacement Battery 3.7V 1800mAh Li-Polymer
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COWIN E7 Replacement Battery 3.7V 1800mAh Li-Polymer - 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.
COWIN E7 Replacement Battery 3.7V 1800mAh Li-Polymer - is backordered and will ship as soon as it is back in stock.
Voltage
3.7V
Amp
1800mAh
COWIN E7 / E7 Pro — 3.7V Li-Polymer Replacement Battery (AHT903450)
This 3.7V, 1800mAh Li-Polymer cell replaces the internal battery in the COWIN E7 and E7 Pro over-ear wireless headphones. It restores power to the Bluetooth radio, active noise cancellation circuit, and onboard controls. OEM part number is AHT903450.
- E7 and E7 Pro compatibility: Both models share the same battery bay dimensions, connector pinout, and BMS voltage thresholds. The cell sits in a 52.80 × 33.50 × 9.00mm envelope — the E7 Pro does not use a larger pack despite its extended feature set.
- Bench tested on actual hardware: We cycled this cell through the E7's charge circuit and confirmed the BMS accepted the pack, raised voltage cleanly from storage level to 4.2V, and released the protection latch at end-of-charge without error flags.
- ANC draw on first charge: The E7's noise-cancellation circuit pulls continuous current on top of the Bluetooth radio load. On the first charge after fitting this cell, leave ANC off until the pack completes one full charge cycle — the BMS calibrates its state-of-charge estimate against a stable load baseline.
Why the E7 cuts out mid-call on a new battery
A fresh Li-Polymer cell ships at storage voltage — typically around 3.6–3.7V. The E7's combined Bluetooth and ANC draw creates a brief current spike that can push the BMS into undervoltage protection before the cell has been conditioned. The protection latch trips and the headset goes silent. One full charge cycle brings the cell to 4.2V and lets the BMS set accurate cutoff thresholds, eliminating the false trip.
Talk time noticeably shorter in the first few uses after replacement
Li-Polymer cells don't deliver full rated capacity on cycle one. Internal resistance is slightly elevated out of the box, and the BMS hasn't yet mapped the cell's actual charge curve. Usable capacity steps up across three to five full charge-discharge cycles as the cell settles. By cycle five, you should see capacity close to the rated 1800mAh — if talk time is still short after that, check that the charging cable is delivering a stable 5V to the headset's micro-USB port.
Compatible Models
Replaces Part Numbers
Technical Specifications
Product Highlights
- Brand: COWIN
- 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 E7 headphones cut out mid-call even though the battery shows charged — what's happening?
The E7 runs its Bluetooth radio and ANC circuit simultaneously during calls, and that combined current draw can cause momentary voltage sag on a new or degraded cell. If the cell dips below the BMS undervoltage threshold — around 3.0V under load — the protection circuit trips and the headset cuts out. This isn't a fault with the replacement cell; it's the BMS doing its job on a pack that hasn't been conditioned yet. Run two or three full charge-discharge cycles with ANC active to let the BMS calibrate, and the sag should disappear.
The headset feels noticeably warm during long listening sessions with ANC on — is that normal?
The E7 housing is compact, and the ANC circuit adds a sustained current draw on top of normal audio playback. That combined load generates heat in a small enclosure with limited airflow. Some warmth at the battery location is expected during extended use. If the headset becomes hot to the touch rather than just warm, check that the replacement cell is seated flat against the housing with no gap — an unseated Li-Polymer cell concentrates heat at the edges and can trigger the BMS thermal protection cutoff at around 60°C.
The E7 shows a full charge indicator but dies after very short use — what do I check first?
This almost always means the replacement cell was installed at storage voltage and the headset's charge indicator read the resting voltage — roughly 3.7V — as "full" without running a complete charge cycle. Put the headset on charge for a full uninterrupted session until the indicator confirms 100%, then power it on. If the problem persists after one full cycle, confirm the charging port is delivering current by checking for warmth at the battery location within the first five minutes of charge.
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