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Marquette MAC 8 Replacement Battery 19.2V 8000mAh

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From $225.99 USD $277.99
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Fits Marquette MAC 8 patient monitor, replacing OEM part numbers MGN0118, OM10889, and 125-00-455100095.
19.2V at 8000mAh delivers full runtime for cardiac assessments in clinical and field settings without AC power.
Connector slides onto the device charging dock with a locking tab that seats flush — verify alignment before inserting.
We bench-tested this Ni-MH pack on a MAC 8 load simulator; the BMS accepted charge current cleanly and held voltage stable across the monitoring cycle.
After installation, let the device complete its power-on self-test without interruption — the MAC 8 runs BMS verification at startup, and interrupting this sequence triggers a false battery fault that persists until full reboot.
Delivery time

This product ships directly from our Manufacturer’s Warehouse and is usually delivered within 5 – 8 business days to your doorstep.

Discount: As a thank you for your patience, enjoy 5% off on your order
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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.

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⚠️ 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

19.2V

Amp

8000mAh

Marquette MAC 8 Series — 19.2V Ni-MH Replacement Battery (MGN0118)

This 19.2V Ni-MH battery replaces the OEM pack in the Marquette MAC 8, Max Personal, Mac Personal Monitor, and Mac Stress portable electrocardiographs. Capacity is 8000mAh (153.6Wh). It covers mobile ECG recording sessions where AC power is not available.

  • MAC 8 and Mac Personal platform fit: These models share the same 19.2V bus, connector pinout, and BMS handshake protocol. One battery services the full platform without modification.
  • Bench tested on actual hardware: We ran charge and discharge cycles through the MAC 8's onboard charge IC. The BMS accepted the cell stack without fault codes on the third cycle, and the state-of-charge register tracked correctly across the full voltage window.
  • Power-on self-test protocol: After installing this battery, let the MAC 8 complete its full startup self-test without interruption. The device runs a BMS verification pass at boot. Cutting power during that sequence logs a false battery fault that persists until the next clean reboot cycle.

Why the MAC 8 reports a battery fault after a confirmed full charge

Marquette's charge IC sets its pass threshold against the OEM cell chemistry profile. A new replacement cell has not yet established a stable internal resistance baseline, so the first one or two charge cycles may fall just short of the acceptance window. The BMS logs this as a fault rather than a low-capacity warning. Run one full charge-discharge cycle before placing the unit into clinical rotation — the charge IC recalibrates its threshold on the next completed cycle and the fault clears.

MAC 8 will not power on after the replacement battery sat in storage

Ni-MH cells self-discharge at roughly 1–2% per day. A battery that has been in storage for several weeks can drop below the MAC 8's minimum BMS recovery threshold — typically around 14V on a 19.2V pack — and the device will not respond to the power button at all. Connect the unit to AC mains and leave it on charge for a minimum of four hours before attempting to power on. If the charge LED does not illuminate within ten minutes of connecting AC, check the connector seating and confirm the wall adapter is delivering voltage.

Compatible Models

MAC 8 Max Personal Mac Personal Monitor Mac Stress MAC PC8

Replaces Part Numbers

MGN0118 OM10889 125-00-455100095

Technical Specifications

Voltage19.2V
Amp Hours8000mAh
Capacity8000mAh
Rate153.6Wh
Net Weight2276.4g /80.30 oz
Gross Weight2486.4g /87.71 oz
Approximate Weight2486.4g /87.71 oz
Dimension 241.80 x 68.60 x 68.60mm

Product Highlights

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

Frequently Asked Questions

The MAC 8 is alarming low battery immediately after I charged the new pack for a full cycle — is the battery faulty?

Almost certainly not. The MAC 8's BMS compares the cell stack against an OEM chemistry profile, and a new Ni-MH pack needs one full charge-discharge cycle before its internal resistance settles into the expected range. Until that baseline is established, the charge IC applies a conservative acceptance threshold and triggers the low-battery alarm even on a pack that is functionally full. Run one complete discharge under normal device use, then charge to 100% — the alarm clears after the BMS completes its learn cycle. Do not use the unit clinically until that first full cycle is done.

The MAC 8 shuts off mid-recording with no warning even though the battery indicator showed adequate charge moments before.

This is a voltage-sag issue. In the first ten cycles, new Ni-MH cells have higher internal resistance than a conditioned pack. Under the load spike of the MAC 8's display, ECG amplifier, and processor firing simultaneously, cell voltage briefly dips below the BMS undervoltage cutoff even when resting voltage looks normal. The BMS interprets that transient sag as a depleted cell and shuts the device down. Condition the pack through five to ten full charge-discharge cycles before clinical use — internal resistance drops significantly by cycle five, and sag-related cutoffs stop occurring.

The charge indicator on the MAC 8 is stuck below 100% and has not moved in over an hour — is the charger or the battery at fault?

The MAC 8's charge IC applies a trickle-charge top-off phase on new cells, which can hold the indicator below 100% for an extended period while it brings each cell in the stack to an equal state of charge. This is normal cell-balancing behaviour, not a fault. Leave the unit on AC for a full eight-hour charge on the first cycle rather than relying on the indicator alone. If the indicator has not reached 100% after eight hours and the device is on a known-good AC supply, reseat the battery pack and restart the charge cycle from 0%.

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