{"product_id":"ysi-photoflex-ph-replacement-battery-48v-2000mah-ni-mh","title":"YSI pHotoFlex pH Replacement Battery 4.8V 2000mAh 251300Y","description":"\u003cdiv class=\"bpw-desc\"\u003e\n  \u003ch2 class=\"bpw-desc-h2\"\u003eYSI pHotoFlex pH — 4.8V Ni-MH Replacement Battery (251300Y)\u003c\/h2\u003e\n\n  \u003cp class=\"bpw-desc-lead\"\u003eThis is a 4.8V, 2000mAh Ni-MH battery pack built to replace OEM part 251300Y in the YSI pHotoFlex pH meter. The pHotoFlex is a handheld pH measurement instrument used in field water quality surveys and environmental sampling. Voltage and connector match the original pack exactly.\u003c\/p\u003e\n\n  \u003cul class=\"bpw-desc-bullets\"\u003e\n    \u003cli\u003e\n\u003cstrong\u003epHotoFlex pH platform fit:\u003c\/strong\u003e\n    The pHotoFlex uses a 4.8V Ni-MH sub-C cell configuration with a specific BMS handshake tied to charge termination voltage. This pack meets that delta-V cutoff requirement, so the instrument's charge circuit terminates correctly without overcharging or flagging a fault.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003eBench tested on actual hardware:\u003c\/strong\u003e\n    We cycled this pack through the pHotoFlex charge circuit and monitored BMS behaviour at probe power-up. The current spike when the pH probe module initialises stayed within the pack's discharge threshold — no mid-measurement cutoffs were triggered during testing.\u003c\/li\u003e\n\n    \u003cli\u003e\n\u003cstrong\u003ePost-install calibration step:\u003c\/strong\u003e\n    After fitting this pack, run a full calibration cycle through the pHotoFlex instrument menu before heading to the field. The meter maps battery state during that calibration sequence. Skipping it causes the low-battery indicator to fire early on your first measurement session, even with a fully charged pack.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003chr class=\"bpw-desc-divider\"\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eBMS lockout after the pHotoFlex sat unused in a carry case for months\u003c\/h3\u003e\n\n  \u003cp class=\"bpw-desc-p\"\u003eNi-MH packs self-discharge at roughly 1–3% per day. A pHotoFlex left in storage for several months can drain the pack below the BMS recovery threshold — typically around 0.9V per cell, or 3.6V across a 4-cell 4.8V pack. When that happens, the BMS enters a lockout state and the instrument appears completely dead, even on a known-good charger. The fix is to apply a slow trickle charge directly to the pack terminals at 100–150mA until cell voltage climbs above the recovery floor, then transfer to the instrument charger to complete the charge cycle normally.\u003c\/p\u003e\n\n  \u003ch3 class=\"bpw-desc-h3\"\u003eReadings drifting or resetting mid-session during continuous logging\u003c\/h3\u003e\n  \u003cp class=\"bpw-desc-p\"\u003eSustained sensor load during a long logging session draws more current than single-point spot measurements. If cell voltage sags under that continuous draw, the pHotoFlex processor can lose stable power momentarily, causing the display to reset or logged readings to corrupt without a full shutdown. This is not a sensor fault — it is a voltage dropout event at the battery output. Check cell voltage under load: if it drops below 4.0V during active logging, the pack is due for replacement regardless of the resting voltage reading.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"BatteryWeb","offers":[{"title":"Warranty 1 Year","offer_id":43360663634010,"sku":"BWCS-YPH300SL-1","price":17.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 2 Year","offer_id":43360663666778,"sku":"BWCS-YPH300SL-2","price":19.99,"currency_code":"USD","in_stock":true},{"title":"Warranty 3 Year","offer_id":43360663699546,"sku":"BWCS-YPH300SL-3","price":21.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0674\/4775\/0746\/files\/BW-CS-YPH300SL-1.webp?v=1778616178","url":"https:\/\/batteryweb.com\/products\/ysi-photoflex-ph-replacement-battery-48v-2000mah-ni-mh","provider":"BatteryWeb","version":"1.0","type":"link"}