{"product_id":"braun-infusion-pump-501-305-replacement-battery-12v-4000mah-ni-mh","title":"Braun Infusion Pump 501-305 12V Replacement Battery 4000mAh","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eBraun Infusion Pump 501-305 — 12V Ni-MH Replacement Battery\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 12V, 4000mAh (48Wh) Ni-MH replacement battery for the Braun Infusion Pump 501-305. It fits directly into the pump's battery bay and restores power to the infusion control system. Use it when the original cell has lost capacity or no longer holds a charge through a full administration cycle.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003eInfusion Pump 501-305 fit:\u003c\/strong\u003e\n    This battery matches the 12V nominal voltage rail and physical footprint the 501-305 pump requires. The BMS in the pump expects a Ni-MH cell at this voltage — substituting a different chemistry or voltage will trigger a persistent battery fault.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this cell through charge and discharge on the bench. The BMS completed handshake and the charge indicator progressed normally. On the first cycle, the charge IC applied a conservative current limit — this is expected behaviour, not a fault.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePower-on self-test after installation:\u003c\/strong\u003e\n    After fitting this battery, let the 501-305 complete its full power-on self-test without interruption. The pump runs a BMS verification routine at startup — cutting power during this sequence logs a false battery fault that persists until the next clean reboot.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eWhy the 501-305 alarms low battery on a freshly charged new cell\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eThe pump's BMS stores a charge profile from the previous cell. When a new Ni-MH cell is installed, the BMS compares early voltage readings against that stored threshold — the new cell's internal resistance differs from a broken-in cell, so the BMS flags it as low even at full charge. This is not a fault with the battery. Running one full charge-discharge cycle allows the BMS to recalibrate its threshold to the new cell's behaviour. After that cycle, the low-battery alarm clears at normal charge levels.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eCharge indicator stuck below 100% on first charge\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eOn the first charge, the pump's charge IC applies a reduced current limit to a cell it has not yet profiled. This causes the indicator to plateau below 100% even after a long charge. The cell is not defective — the IC is being conservative with an unprofiled Ni-MH pack. Allow the battery to complete a full discharge down to the pump's low-battery cutoff, then run a full charge. After this first complete cycle, the charge IC updates its profile and the indicator reaches 100% correctly.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43381494218842,"sku":"BWCS-GME106MD-1","price":98.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43381494251610,"sku":"BWCS-GME106MD-2","price":115.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43381494284378,"sku":"BWCS-GME106MD-3","price":128.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-GME106MD-1.webp?v=1778901266","url":"https:\/\/batteryweb.com\/products\/braun-infusion-pump-501-305-replacement-battery-12v-4000mah-ni-mh","provider":"BatteryWeb","version":"1.0","type":"link"}