{"product_id":"motorola-evx-531-replacement-battery-74v-2600mah-li-ion","title":"Motorola EVX-531 Compatible Battery 7.4V 2600mAh AAJ67X001","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eMotorola EVX-531 \/ VX-261 Series — 7.4V Li-ion Replacement Battery (AAJ67X001)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis 7.4V 2600mAh Li-ion battery replaces the AAJ67X001, AAJ68X001, AAK66X501, FNB-V133Li, FNB-V134Li, and FNB-V138Li packs across the EVX-531, EVX-534, EVX-539, and VX-261 series. It fits the same physical slot and connects to the same four-pin contact rail used across these Motorola and Vertex Standard platforms. Capacity is 2600mAh — confirmed against the original spec.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eEVX-531 \/ EVX-534 \/ EVX-539 \/ VX-261 platform fit:\u003c\/strong\u003e\n    These models share the same contact rail geometry, BMS handshake voltage range, and charge-termination protocol — which is why one pack covers all of them. The connector keys and housing dimensions match across the group without modification.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this pack through full charge and discharge on an EVX-531 body and monitored BMS cutoff behaviour under PTT transmit loads. The protection circuit responded correctly to both overcurrent and thermal events without nuisance tripping.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFirst insertion on a Vertex Standard dock:\u003c\/strong\u003e\n    If the charger dock shows a fault LED on first insertion, remove the pack, wipe the gold contact strip with a dry cloth, and reseat firmly. The EVX platform requires a clean contact cycle to complete the BMS handshake before charging begins — this is not a faulty 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 EVX-531 cuts out mid-transmission on a new battery\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe EVX-531 draws a sharp current spike the moment PTT is pressed — transmit current can jump to 1.8–2A in under 100ms. A new pack shipped at storage voltage (around 3.7V per cell) has higher internal impedance than a fully charged cell, which causes the BMS to read that spike as an overcurrent event and trip. The fix is a full charge cycle before first field use — a fully charged cell at 4.2V per cell handles the transmit surge without tripping. One complete charge resolves this.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eBar indicator showing one fewer bar than expected on a new pack\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe EVX-531 uses a voltage-threshold bar display — each bar corresponds to a voltage window, not a calculated capacity percentage. New cells arrive at storage voltage, typically 3.6–3.75V per cell, which maps to one or two bars even though the pack is not depleted. After a full charge brings each cell to 4.2V, the display will read the correct level. If bars remain low after a verified full charge, check that the dock contact pins are clean and making full contact with the pack strip.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43426336505946,"sku":"BWCS-FVX450TW-1","price":43.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43426336538714,"sku":"BWCS-FVX450TW-2","price":50.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43426336571482,"sku":"BWCS-FVX450TW-3","price":55.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-FVX450TW-1.webp?v=1779930720","url":"https:\/\/batteryweb.com\/products\/motorola-evx-531-replacement-battery-74v-2600mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}