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HP iPAQ RX1900 Replacement Battery 3.7V 1200mAh PE2018AS

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From $22.99 USD $28.99
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Fits HP iPAQ RX1900, RX1950, RX1955 models; replaces OEM part PE2018AS and cross-references 395780-001, HSTNN-H09C-WL, 398687-001, 399858-001, 35H00063-00M.
3.7V, 1200mAh lithium-ion cell delivers 4.44Wh to sustain your PDA through a full business day of email, calendar sync, and wireless data.
Connector slides straight into the battery slot with no adapter needed; locking tab seats flush against the compartment wall.
We bench-tested this cell in an RX1950 unit; BMS accepted the pack on first insertion, and voltage held steady under moderate load.
Perform a full data sync to your host computer before removing the old battery — the iPAQ stores open files and application state in RAM powered by the main cell, and removing power without syncing causes data loss.
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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.

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.

Voltage

3.7V

Amp

1200mAh

HP iPAQ RX1900 / RX1950 / RX1955 — 3.7V Li-ion Replacement Battery (PE2018AS)

This 3.7V, 1200mAh Li-ion cell replaces the original battery in the HP iPAQ RX1900, RX1950, and RX1955 pocket PC handhelds. It matches OEM part numbers PE2018AS, 395780-001, HSTNN-H09C-WL, 398687-001, 399858-001, and 35H00063-00M. The cell fits the same physical bay and connects to the same three-pin contact as the factory unit.

  • RX1900 / RX1950 / RX1955 platform fit: All three models share the same battery bay dimensions and three-pin BMS contact layout. The voltage rail, connector pitch, and thermistor pin are identical across the series, so one cell covers all three.
  • Bench tested on actual hardware: We ran this cell on an RX1950 unit and confirmed the BMS handshake completed correctly at first connection. The device read battery status accurately in Windows Mobile and charged without error through the cradle.
  • RAM data protection before swap: Perform a full ActiveSync or Windows Mobile Device Center sync to your host computer before removing the old battery. The iPAQ stores open files and application state in SRAM powered directly by the main cell — cutting power without syncing first will erase unsaved data.

Why the iPAQ RX1900 loses all data when the battery goes flat

The RX1900 uses SRAM for working memory rather than flash-backed storage. SRAM requires constant voltage to retain data — drop below roughly 3.0V and the contents are gone. Unlike a modern smartphone, there is no background save to internal flash when the battery drains. A battery that has degraded to low capacity can cross that threshold quickly under normal use, wiping open applications and contacts without warning. Keeping the cell charged above 3.5V is the only way to protect in-memory data between syncs.

iPAQ shows "Charging" but percentage stays at zero after new battery install

A deeply discharged Li-ion cell can sit below the BMS activation threshold — typically around 2.5V — which causes the device to report charging without the percentage moving. The BMS locks out full current delivery until the cell recovers to a safe voltage. Connect the iPAQ to the cradle or USB charger and leave it for 20–30 minutes without powering it on. Once the cell reaches approximately 3.0V, the BMS releases and normal charging resumes.

Compatible Models

iPAQ RX1900 iPAQ RX1950 iPAQ RX1955

Replaces Part Numbers

PE2018AS 395780-001 HSTNN-H09C-WL 398687-001 399858-001 35H00063-00M

Technical Specifications

Voltage3.7V
Amp Hours1200mAh
Capacity1200mAh
Rate4.44Wh
Net Weight23.7g /0.84 oz
Gross Weight48.7g /1.72 oz
Approximate Weight48.7g /1.72 oz
Dimension 51.81 x 38.98 x 6.18mm

Product Highlights

  • Brand: HP
  • 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

My iPAQ RX1950 lost all my contacts and calendar entries when I swapped the battery — why did that happen?

The RX1950 stores contacts, calendar data, and open application state in SRAM, which needs live voltage to hold its contents. The moment the old battery came out and before the new one made contact, that voltage dropped to zero and the SRAM wiped. Before any future battery swap, run a full sync via ActiveSync or Windows Mobile Device Center so a copy exists on the host PC — that sync is the only backup the device creates automatically.

The iPAQ RX1955 won't boot at all after fitting the new battery — the screen just stays black.

A new cell shipped in storage state can arrive at 30–50% charge, which may be below the minimum voltage the RX1955 boot sequence needs to initialise. The device will not attempt a boot if the cell reads under approximately 3.2V. Connect it to the charging cradle or a USB source and leave it for at least 20 minutes before pressing the power button. If the charge indicator LED activates, the cell is recovering and the unit will boot normally once voltage climbs.

Battery life on my RX1900 dropped noticeably after I started using Wi-Fi sync instead of the cradle — is the battery at fault?

The Wi-Fi radio on the RX1900 draws significantly more current than the device pulls in standby or during basic PIM use. A 1200mAh cell at full charge handles this, but if the battery has accumulated shallow cycles without a full charge, usable capacity shrinks faster than the percentage indicator suggests. Charge the device to 100% via the cradle rather than USB where possible, and allow it to reach a full 4.2V before disconnecting — partial charges repeated over time accelerate capacity fade in this cell chemistry.

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