{"product_id":"motorola-gp688-replacement-battery-75v-1100mah-ni-mh","title":"Motorola GP688 Replacement Battery PMNN4000C 7.5V 1100mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eMotorola GP688 — 7.5V Ni-MH Replacement Battery (PMNN4000C)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 7.5V, 1100mAh Ni-MH battery for the Motorola GP688 portable two-way radio. It replaces OEM packs PMNN4000C, PMNN4001A, PMNN4002C, and several related part numbers across the GP688 platform. Voltage and connector match the original spec — no modifications needed.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eGP688 platform compatibility:\u003c\/strong\u003e\n    The GP688 series uses a shared 7.5V Ni-MH rail with a consistent connector and BMS handshake across all listed OEM part numbers. Minor suffix changes (A, B, C) reflect production revisions, not different battery architectures — this pack covers the full range.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We ran this pack through charge and transmit cycles on the GP688. The BMS handled PTT-triggered current spikes cleanly, held voltage within the radio's acceptance window, and passed the dock's charge-acceptance handshake on first insertion.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFirst-insertion contact check:\u003c\/strong\u003e\n    If the charger dock shows a fault LED after fitting this battery, remove it, wipe the gold contact strip with a dry cloth, and reseat firmly. The GP688 dock requires a clean contact cycle to complete the BMS handshake before charging begins — this is not a fault with the pack.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the GP688 cuts out mid-transmission on a new Ni-MH pack\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eNi-MH cells ship at partial storage charge — typically 40–60% of rated capacity. During a PTT press, the transmitter draws a sharp current spike that the cell can't sustain cleanly at low state-of-charge. The BMS reads this as an overcurrent condition and briefly cuts output. Running two full charge-discharge cycles before field use brings the cells to full capacity and eliminates this behaviour.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eBar indicator showing one fewer bar than expected after fitting this pack\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe GP688 reads charge level by comparing pack voltage against fixed thresholds — it has no way to measure true cell capacity. A new Ni-MH pack at storage voltage sits just below the top threshold, so the radio displays one bar short of full. This is not a cell fault. Charge the pack completely in the dock; once voltage reaches 8.4–8.5V at end-of-charge, the indicator will read full on next power-on.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43426341126234,"sku":"BWCS-MGP630TW-1","price":34.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43426341159002,"sku":"BWCS-MGP630TW-2","price":39.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43426341191770,"sku":"BWCS-MGP630TW-3","price":43.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-MGP630TW-1.webp?v=1779930783","url":"https:\/\/batteryweb.com\/products\/motorola-gp688-replacement-battery-75v-1100mah-ni-mh","provider":"BatteryWeb","version":"1.0","type":"link"}