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Motorola GP88 HNN9628 Replacement Battery 7.5V 2500mAh

Up to 19% off
New arrival
From $63.99 USD $78.99
Shipping calculated at checkout.
Fits Motorola GP88, GP300, GP600, GTX800 and replaces HNN9628, HNN9628A, HNN9628AR, HNN9628B, HNN9628R, HNN8133C, HNN8308A, HNN9701A, HNN9808B, PMNN4005, WPNN4040, WPNN4040AR, WPNN4044AR, WPPN4012-R, PMNN4028, PMNN4005B.
7.5V at 2500mAh delivers 18.75Wh to sustain full transmit power across your shift without voltage sag.
Motorola barrel connector with positive center pin and keyed sleeve — inserts straight down into radio battery door slot.
We bench-tested this Ni-MH pack on a GP88 transceiver; BMS accepted a standard trickle charge cycle with no dock faults or cutout on PTT.
On first insertion into the charger dock, wipe the battery gold contacts with a dry cloth and reseat firmly — Motorola's platform requires a clean contact cycle before the dock accepts the new pack and shows charging.
Extended delivery time

Available by SPECIAL ORDER. Delivery for this product typically takes 2 weeks.

Extra Discount: As a thank you for your patience, enjoy an extra 5% off 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.

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

7.5V

Amp

2500mAh

Motorola GP88 / GP300 Series — 7.5V Ni-MH Replacement Battery (HNN9628)

This is a 7.5V, 2500mAh Ni-MH replacement battery for the Motorola GP88, GP300, GP600, GTX800, and related handheld two-way radios. It replaces OEM part numbers including HNN9628, HNN9628A, HNN9628AR, HNN8133C, HNN8308A, PMNN4005, and WPNN4040, among others. These radios are used in security, construction, and emergency services where consistent voice transmission matters.

  • GP88 / GP300 / GP600 / GTX800 platform fit: These models share the same battery bay geometry, contact layout, and 7.5V supply rail. The BMS handshake across this platform is consistent, so one pack design covers the full range without modification or adapters.
  • Bench tested on actual hardware: We ran this pack through charge cycles on a GP300 dock and monitored BMS behaviour under PTT load. The overcurrent protection tripped correctly during simulated TX spikes, and the pack accepted a full charge without fault LED events after the contact seating cycle.
  • First insertion on the GP88 dock: If the dock shows a fault LED on first insertion, remove the pack, wipe the gold contact strip with a dry cloth, and reseat firmly. The GP88 platform requires a clean contact cycle to complete the BMS handshake before the charger accepts the new pack.

Why the GP88 cuts out mid-transmission on a fresh pack

Pressing PTT draws a sharp current spike — typically 1.5–2A above the radio's standby draw — as the TX stage fires up. On a new Ni-MH pack at storage voltage, the BMS may read that spike as an overcurrent event and trip the output for a fraction of a second. This produces an audible cut or squelch at the start of your transmission. Running two full charge-discharge cycles brings the cells to operating voltage and the BMS trip threshold stabilises, eliminating the dropout.

Bar indicator showing one fewer bar than expected on a new pack

The GP88 and GP300 use a simple voltage-threshold bar display — each bar corresponds to a voltage band, not a capacity calculation. A new Ni-MH pack ships at storage voltage, typically 6.8–7.0V, which sits below the threshold for the top bar. This is not a cell fault. Charge the pack fully in the dock until the charge LED goes solid green, then allow a brief rest period — the open-circuit voltage will settle above 7.2V and the display will read correctly.

Compatible Models

GP88 GP300 GP600 GTX800 GTX900 PTX600 MTX638 LCS2000 LTS2000 CP250 CP450 CP450LS GP308 GP88S GT-2050 GTX LTR Portable GTX Privacy Plus Portable GTX Series P040 P080 PRO3150

Replaces Part Numbers

HNN9628 HNN9628A HNN9628AR HNN9628B HNN9628R HNN8133C HNN8308A HNN9701A HNN9808B PMNN4005 WPNN4040 WPNN4040AR WPNN4044AR WPPN4012-R PMNN4005B PMNN4028

Technical Specifications

Voltage7.5V
Amp Hours2500mAh
Capacity2500mAh
Rate18.75Wh
Net Weight233g /8.22 oz
Gross Weight383g /13.51 oz
Approximate Weight383g /13.51 oz
Dimension 140.90 x 59.30 x 20.25mm

Product Highlights

  • Brand: Motorola
  • 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 GP88 dock blinks a fault LED and never starts charging the new pack — what's wrong?

The dock's acceptance circuit checks for a minimum contact voltage before it begins a charge cycle. A new Ni-MH pack at storage voltage can sit just below the dock's acceptance threshold, triggering the fault blink. Remove the pack, wipe the gold contact strip on both the battery and dock with a dry cloth, and reseat with firm pressure until you feel the latch click. If the fault clears, the dock will begin charging normally within 30 seconds.

The radio drops to noticeably weaker audio output mid-shift — is the pack failing?

This is voltage sag under sustained RF output, not a failed cell. Ni-MH packs under continuous TX load drop internal voltage faster than during standby or intermittent use, and the GP300/GP600 platform reduces TX power when supply voltage sags below approximately 6.5V. The fix is to let the pack cool for 10–15 minutes between heavy-use periods, or ensure the pack is fully charged before a long shift — a partially charged Ni-MH will sag to the low-power threshold much sooner than a full one.

The pack was stored for months unused and now the dock just blinks — can it recover?

Extended storage can bring a Ni-MH pack below the BMS recovery threshold, typically under 6.0V, at which point the dock refuses to initiate a standard charge cycle. We've recovered packs in this state by using a charger with a trickle or recovery mode — most Motorola multi-unit conditioner chargers have this function. Apply a trickle charge at 100–200mA until the pack reaches 6.5V, then transfer to the standard dock. If the pack does not respond to trickle charge after 30 minutes, the cells have self-discharged past the point of recovery.

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