{"product_id":"vex-iq-controller-replacement-battery-37v-900mah-li-ion","title":"VEX IQ Controller 3.7V Replacement Battery VEX-228-2779 900mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eVEX IQ Controller — 3.7V Li-ion Replacement Battery (VEX-228-2779)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 3.7V, 900mAh lithium-ion cell that replaces the internal battery in the VEX IQ Controller. The IQ Controller is the central processing unit of VEX IQ robot kits — it coordinates motor outputs and sensor inputs during competitions and build sessions. Voltage and capacity match the OEM specification exactly.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eVEX IQ Controller fit:\u003c\/strong\u003e\n    The IQ Controller runs a single lithium-ion cell at 3.7V nominal. The BMS in this unit monitors cell voltage directly — any deviation from the expected voltage window triggers a low-battery warning or shutdown before a match cycle completes. This replacement cell sits within that window.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell under load conditions that replicate motor-drive draw across the IQ Controller's output channels. The BMS accepted the cell without error flags, and charge termination triggered correctly at full capacity.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eFuel gauge recalibration after swap:\u003c\/strong\u003e\n    After installing this cell, run one complete discharge down to the controller's low-battery cutoff, then charge fully before use. The IQ Controller's fuel gauge IC reads state-of-charge against a stored cell profile — a full cycle forces it to remap against the new cell's actual discharge curve.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the IQ Controller shuts down mid-match even with battery showing charge\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe IQ Controller cuts power when cell voltage drops below approximately 3.0V under load — even if the on-screen indicator still shows remaining charge. During a match, motor-drive current spikes cause a momentary voltage sag on a degraded or deeply discharged cell. The BMS reads that sag as a brownout condition and triggers an emergency cutoff to protect the cell. A new cell at full state-of-charge maintains voltage above the cutoff threshold even during peak motor demand.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eIQ Controller battery percentage stuck or jumping after cell replacement\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eThe fuel gauge IC in the IQ Controller stores a discharge curve calibrated to the previous cell's internal resistance and capacity profile. When a new cell is installed, that stored curve no longer matches the actual cell, so the reported percentage can freeze, skip, or drop suddenly. This is not a fault with the replacement cell — it is the gauge IC working from stale data. Run one full discharge-to-cutoff followed by a full charge cycle, and the IC will recalibrate to the new cell's actual curve.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43405025640538,"sku":"BWCS-MY890SL-1","price":23.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43405025673306,"sku":"BWCS-MY890SL-2","price":27.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43405025706074,"sku":"BWCS-MY890SL-3","price":29.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-MY890SL-1.webp?v=1778767243","url":"https:\/\/batteryweb.com\/products\/vex-iq-controller-replacement-battery-37v-900mah-li-ion","provider":"BatteryWeb","version":"1.0","type":"link"}