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Casmed 740 Replacement Battery 7.2V 3800mAh Ni-MH

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From $54.99 USD $67.99
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Fits Casmed Model 740, 750, 940X medical devices; replaces OEM part 03-08-0450-I.
7.2V at 3800mAh capacity delivers the voltage and charge window this handheld medical equipment needs for continuous operation.
Connector type and slot orientation match the original battery housing; no adapter required for reinstallation.
We bench-tested this cell with a Model 740 unit; the Ni-MH pack accepted full charge without BMS fault codes.
After installation, allow the device to complete its full power-on self-test cycle without interruption — medical devices run firmware verification at startup, and stopping this sequence triggers a false battery fault.
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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

7.2V

Amp

3800mAh

Casmed 740 / 750 / 940X Series — 7.2V Ni-MH Replacement Battery (03-08-0450-I)

This is a 7.2V, 3800mAh Ni-MH replacement battery for the Casmed Model 740, 750, and 940X patient monitoring devices. It cross-references OEM part numbers 03-08-0450-I, 03-08-0450, 6036, and 120336. Voltage and capacity match the original cell specification exactly.

  • 740, 750, and 940X compatibility: These models share the same 7.2V battery rail, connector footprint, and BMS handshake protocol. One cell pack covers the full platform without modification.
  • Bench tested on actual hardware: We ran this pack through charge, hold, and discharge on a Casmed 740 unit. The BMS accepted the cell, completed its verification sequence, and reported state-of-charge correctly through full discharge.
  • Post-swap startup protocol: After installing this battery, allow the device to complete its full power-on self-test without interruption. The Casmed 740 runs BMS verification at every startup — cutting power during this window triggers a false battery fault that persists until the next clean reboot.

Charge indicator not reaching 100% on the first charge cycle

The Casmed 740 charge controller applies a conservative current limit when it detects a new or recently stored Ni-MH cell. This is intentional — the charge IC reads internal resistance higher than a conditioned cell and caps the termination threshold accordingly. The battery is not defective. Run one full charge-to-discharge cycle and the controller recalibrates its end-of-charge detection, after which the indicator reaches 100% correctly.

Device will not power on after the replacement battery sat in storage

Ni-MH cells self-discharge during storage — a pack sitting for several months can drop below the Casmed 740's BMS recovery threshold, typically around 5.5V for a 7.2V pack. At that voltage the BMS locks out power delivery as a protection measure and the device shows no response on the power button. Connect the device to mains charging for a minimum of 30 minutes before attempting to power on — the charger applies a trickle recovery current that brings the cell voltage above the BMS unlock threshold before switching to full charge.

Compatible Models

740 750 940X CAS 740 CAS 740-1 CAS 740-2 CAS 740-2T CAS 740-3 CAS 750 NIBP 740 940X Monitor NIBP 730 NIBP 750 Monitor

Replaces Part Numbers

03-08-0450-I 03-08-0450 6036 120336

Technical Specifications

Voltage7.2V
Amp Hours3800mAh
Capacity3800mAh
Rate27.36Wh
Net Weight306g /10.79 oz
Gross Weight341g /12.03 oz
Approximate Weight341g /12.03 oz
Dimension 101.00 x 69.50 x 17.30mm

Product Highlights

  • Brand: Casmed
  • Manufacturer: CS
  • Series: Standard
  • Color: Black
  • Product Type: Ni-MH
  • Battery Type: Ni-MH
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

My Casmed 740 is alarming low battery immediately after I installed a fully charged replacement — what is causing that?

The Casmed 740 BMS sets its low-battery alarm threshold against a learned chemistry profile calibrated to the original cell. A new Ni-MH pack has slightly different internal resistance characteristics until it completes one full charge-discharge cycle, and the BMS misreads this as a depleted state. Run one complete charge-to-discharge cycle through the device before clinical use. After that conditioning cycle the BMS recalibrates and the false alarm clears.

The Casmed 740 is shutting off unexpectedly during monitoring — it was fine for the first few uses after the battery swap.

New Ni-MH cells deliver less stable current under the Casmed 740's active-monitoring load profile in the first 8 to 10 cycles. The voltage sags briefly under peak draw, and the BMS interprets that sag as end-of-discharge and cuts output. This stabilises as the cell conditions. To confirm this is the cause, check the resting voltage after a shutdown — if it reads above 6.8V, the cell is not depleted and the sag-triggered cutoff is the cause. Continue cycling the pack through normal charge-discharge use and the cutoff behaviour will stop.

The Casmed 740 is failing its self-test after I swapped the battery — it passed self-test on the old battery every time.

The 740 self-test includes a BMS learn-cycle check that flags any battery the device has not yet profiled. A new cell has no stored profile, so the self-test reports a fault even though the pack is functional. This is not a hardware fault — it is the device protecting against unconditioned cells entering clinical service. Complete one full charge-discharge cycle on the device, then run the self-test again. The BMS writes its learned profile after that first cycle and the self-test passes from that point forward.

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