{"product_id":"millertech-12v-300ah-heated-marine-lithium-battery-bluetooth-lifepo4-deep-cycle","title":"MillerTech 12V 300Ah Heated Marine Lithium Battery – Bluetooth LiFePO4 - Deep Cycle","description":"\n\u003cp style=\"font-size:18px;\"\u003eThe MillerTech 12V 300Ah Sports Series (Heated) is a lithium iron phosphate (LiFePO4) deep-cycle marine battery built to run high-demand electronics and house loads through a full day on the water. With 300Ah of capacity and Bluetooth monitoring, it keeps fish finders, live sonar, livewell and bilge pumps, lights, radios, and other 12-volt gear powered without the mid-day drop-off common to lead-acid batteries.\u003c\/p\u003e\n\u003cp style=\"font-size:18px;\"\u003eBecause LiFePO4 delivers close to its full rated capacity from charge to cutoff, one battery can cover a demanding electronics setup and still hold reserve power. It also runs 12-volt trolling motors, and it can be wired into 24V or 36V systems when you need higher voltage. Beyond the boat, it fits RV house power, solar energy storage, off-grid cabins, and backup power.\u003c\/p\u003e\n\u003cp style=\"font-size:18px;\"\u003eThe built-in heater sets this model apart for cold-weather use. When temperatures reach freezing and a charger is connected, the heater warms the cells so the battery can charge safely in conditions that would normally prevent a standard lithium battery from charging. That makes it a practical choice for early-spring, late-fall, ice-season, and cold-climate boaters and off-grid users.\u003c\/p\u003e\n\u003cp style=\"font-size:18px;\"\u003eIt is built with a high-output BMS, pure brass terminals, dual stainless steel breathable vents, a sealed marine-grade case, and an integrated carry handle, and it is backed by a 10-year no-questions-asked warranty.\u003c\/p\u003e\n\n\u003ch3\u003eFeatures \u0026amp; Benefits\u003c\/h3\u003e\n\u003cul style=\"font-size:18px;\"\u003e\n\u003cli style=\"font-size:18px;\"\u003e\n\u003cstrong\u003e300Ah \/ 3,840Wh capacity: \u003c\/strong\u003ea large energy reserve that runs electronics, accessories, and 12-volt loads through long days, so you spend less time watching the charge level.\u003cbr\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli style=\"font-size:18px;\"\u003e\n\u003cstrong\u003eBuilt-in self-heating: \u003c\/strong\u003ethe internal heater engages in freezing conditions using power from your connected charger, letting the battery charge safely in cold weather when a standard lithium battery cannot.\u003cbr\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli style=\"font-size:18px;\"\u003e\n\u003cstrong\u003eLow-temperature charging protection: \u003c\/strong\u003ethe BMS guards the cells against cold-charge damage, protecting long-term battery health.\u003cbr\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli style=\"font-size:18px;\"\u003e\n\u003cstrong\u003eBluetooth monitoring: \u003c\/strong\u003ethe MillerTech App shows real-time state of charge, voltage, and current draw, giving you an accurate picture of remaining power on the water.\u003cbr\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli style=\"font-size:18px;\"\u003e\n\u003cstrong\u003eHigh-output BMS with 150A continuous rating: \u003c\/strong\u003esteady output under heavy load, with protection against overcharge, over-discharge, short circuit, and over-temperature.\u003cbr\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli style=\"font-size:18px;\"\u003e\n\u003cstrong\u003eLiFePO4 deep-cycle chemistry: \u003c\/strong\u003eprovides close to full usable capacity and a long service life, unlike lead-acid batteries that should only be discharged about halfway.\u003cbr\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli style=\"font-size:18px;\"\u003e\n\u003cstrong\u003eLightweight for its capacity: \u003c\/strong\u003eat 62.3 lbs it replaces a much heavier bank of lead-acid batteries of similar usable capacity.\u003cbr\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli style=\"font-size:18px;\"\u003e\n\u003cstrong\u003eMarine-grade construction: \u003c\/strong\u003esealed case, pure brass terminals for strong conductivity, dual stainless steel vents to reduce condensation, and an integrated carry handle for easier installation.\u003cbr\u003e\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli style=\"font-size:18px;\"\u003e\n\u003cstrong\u003e10-year no-questions-asked warranty: \u003c\/strong\u003elong-term coverage from the manufacturer, including shipping for repair or replacement during the warranty period.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eApplications \u0026amp; Compatibility\u003c\/h3\u003e\n\u003cp style=\"font-size:18px;\"\u003e\u003cstrong\u003eRecommended applications\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul style=\"font-size:18px;\"\u003e\n\u003cli style=\"font-size:18px;\"\u003eMarine electronics and house power (fish finders, GPS, live and forward-facing sonar, VHF radios, stereo systems)\u003c\/li\u003e\n\u003cli style=\"font-size:18px;\"\u003eMarine accessories (livewell and aerator pumps, bilge pumps, deck and cabin lighting)\u003c\/li\u003e\n\u003cli style=\"font-size:18px;\"\u003e12-volt trolling motors on a single battery, or 24V\/36V systems when wired in series\u003c\/li\u003e\n\u003cli style=\"font-size:18px;\"\u003eRV and camper house power\u003c\/li\u003e\n\u003cli style=\"font-size:18px;\"\u003eSolar energy storage and off-grid systems\u003c\/li\u003e\n\u003cli style=\"font-size:18px;\"\u003eBackup and emergency power\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp style=\"font-size:18px;\"\u003e\u003cstrong\u003eSuitable for\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul style=\"font-size:18px;\"\u003e\n\u003cli style=\"font-size:18px;\"\u003eBass boats, center consoles, bay boats, and pontoons (electronics and house power)\u003c\/li\u003e\n\u003cli style=\"font-size:18px;\"\u003eJon boats and aluminum boats running 12-volt trolling motors\u003c\/li\u003e\n\u003cli style=\"font-size:18px;\"\u003eRVs, campers, and vans\u003c\/li\u003e\n\u003cli style=\"font-size:18px;\"\u003eOff-grid cabins and solar setups\u003c\/li\u003e\n\u003cli style=\"font-size:18px;\"\u003eBackup power systems\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp style=\"font-size:18px;\"\u003e\u003cstrong\u003eSeries and parallel compatibility\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul style=\"font-size:18px;\"\u003e\n\u003cli style=\"font-size:18px;\"\u003eWire in parallel to keep 12-volt output and add capacity for longer runtime.\u003c\/li\u003e\n\u003cli style=\"font-size:18px;\"\u003eWire in series with up to four batteries for 24V, 36V, or 48V systems; capacity stays the same as a single battery. MillerTech recommends parallel wiring for longer battery life where possible, and offers dedicated 24V, 36V, and 48V batteries for higher-voltage needs.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp style=\"font-size:18px;\"\u003e\u003cstrong\u003eFitment\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul style=\"font-size:18px;\"\u003e\n\u003cli style=\"font-size:18px;\"\u003eGroup 50 case measuring 13.5 in x 9.6 in x 10.5 in. It will not fit a standard Group 24, 27, or 31 tray. A battery tray sized for the 12V 300Ah footprint is available separately.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003ctable style=\"font-size:18px; border-collapse: collapse; width: 100%;\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e\u003cstrong\u003eNominal voltage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e12.8V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e\u003cstrong\u003eSystem voltage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e12V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e\u003cstrong\u003eCapacity\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e300Ah\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e\u003cstrong\u003eEnergy\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e3,840Wh\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e\u003cstrong\u003eRound-trip efficiency\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e98%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e\u003cstrong\u003eChemistry\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003eLithium iron phosphate (LiFePO4)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e\u003cstrong\u003eCell type\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003ePrismatic\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e\u003cstrong\u003eBattery management system\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003eYes, high-output BMS\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e\u003cstrong\u003eBluetooth monitoring\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003eYes (MillerTech App)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e\u003cstrong\u003eBuilt-in heater\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e\u003cstrong\u003eLow-temperature charging protection\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e\u003cstrong\u003eMax charge voltage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e14.6V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e\u003cstrong\u003eMax continuous charge\/discharge current\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e150A\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e\u003cstrong\u003ePeak discharge current\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e400A (5 seconds)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e\u003cstrong\u003eLow-voltage cutoff\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e10V\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e\u003cstrong\u003eOperating temperature\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e-4°F to 140°F\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e\u003cstrong\u003eTerminals\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003ePure brass with M8 stainless bolts (torque to 10 ft-lbs)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e\u003cstrong\u003eEnclosure\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003eSealed marine-grade case, dual stainless steel vents, integrated carry handle, water-resistant (not rated for submersion)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e\u003cstrong\u003eGroup size\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e50\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e\u003cstrong\u003eDimensions\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e13.5 in x 9.6 in x 10.5 in\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e\u003cstrong\u003eWeight\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e62.3 lbs\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e\u003cstrong\u003eWarranty\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"font-size:18px; border: 1px solid #ddd; padding: 8px;\"\u003e10 years\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003cstyle\u003e\n.lbs-faq{font-size:18px;max-width:100%;}\n.lbs-faq .lbs-faq-item{border-bottom:1px solid #e2e2e2;}\n.lbs-faq input[type=\"checkbox\"]{position:absolute;opacity:0;height:0;width:0;}\n.lbs-faq label{display:block;cursor:pointer;padding:16px 30px 16px 0;font-weight:600;font-size:18px;position:relative;}\n.lbs-faq label::after{content:\"+\";position:absolute;right:6px;top:14px;font-size:22px;line-height:1;}\n.lbs-faq input[type=\"checkbox\"]:checked + label::after{content:\"\\2013\";}\n.lbs-faq .lbs-faq-answer{max-height:0;overflow:hidden;transition:max-height .3s ease;}\n.lbs-faq input[type=\"checkbox\"]:checked ~ .lbs-faq-answer{max-height:2000px;}\n.lbs-faq .lbs-faq-answer p{padding:0 0 16px;font-size:18px;margin:0;}\n\u003c\/style\u003e\n\u003cdiv class=\"lbs-faq\"\u003e\n\u003cdiv class=\"lbs-faq-item\"\u003e\n\u003cinput type=\"checkbox\" id=\"faq-12300-1\"\u003e \u003clabel for=\"faq-12300-1\"\u003eWhat can this battery power on my boat?\u003c\/label\u003e\n\u003cdiv class=\"lbs-faq-answer\"\u003e\n\u003cp style=\"font-size: 18px;\"\u003eIt supplies 12-volt power for marine electronics and house loads, including fish finders, GPS and live sonar units, VHF radios, livewell and bilge pumps, deck and cabin lights, and stereo systems. The 300Ah capacity is sized to run several of these through a full day.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"lbs-faq-item\"\u003e\n\u003cinput type=\"checkbox\" id=\"faq-12300-2\"\u003e \u003clabel for=\"faq-12300-2\"\u003eCan I use it with a trolling motor?\u003c\/label\u003e\n\u003cdiv class=\"lbs-faq-answer\"\u003e\n\u003cp style=\"font-size: 18px;\"\u003eYes. A single battery powers a 12-volt trolling motor. For 24-volt or 36-volt trolling motors, wire two or three batteries in series, or use a MillerTech battery built for that voltage.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"lbs-faq-item\"\u003e\n\u003cinput type=\"checkbox\" id=\"faq-12300-3\"\u003e \u003clabel for=\"faq-12300-3\"\u003eCan I wire two or three together for a 24V or 36V system?\u003c\/label\u003e\n\u003cdiv class=\"lbs-faq-answer\"\u003e\n\u003cp style=\"font-size: 18px;\"\u003eYes. Most MillerTech batteries can be wired in series with up to four batteries, giving 24V, 36V, or 48V. Capacity stays the same as a single battery. MillerTech recommends parallel wiring for longer battery life where possible, and offers dedicated 24V, 36V, and 48V batteries for higher-voltage systems.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"lbs-faq-item\"\u003e\n\u003cinput type=\"checkbox\" id=\"faq-12300-4\"\u003e \u003clabel for=\"faq-12300-4\"\u003eCan I connect batteries in parallel for more runtime?\u003c\/label\u003e\n\u003cdiv class=\"lbs-faq-answer\"\u003e\n\u003cp style=\"font-size: 18px;\"\u003eYes. Wiring batteries in parallel keeps the voltage at 12V and adds their capacity together, which increases runtime.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"lbs-faq-item\"\u003e\n\u003cinput type=\"checkbox\" id=\"faq-12300-5\"\u003e \u003clabel for=\"faq-12300-5\"\u003eWhat charger should I use?\u003c\/label\u003e\n\u003cdiv class=\"lbs-faq-answer\"\u003e\n\u003cp style=\"font-size: 18px;\"\u003eUse a charger with a lithium (LiFePO4) profile that charges to 14.6V. MillerTech makes chargers matched to their batteries. A standard lead-acid or AGM charger may power the battery but often will not bring it to a true full charge.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"lbs-faq-item\"\u003e\n\u003cinput type=\"checkbox\" id=\"faq-12300-6\"\u003e \u003clabel for=\"faq-12300-6\"\u003eHow long does it take to recharge?\u003c\/label\u003e\n\u003cdiv class=\"lbs-faq-answer\"\u003e\n\u003cp style=\"font-size: 18px;\"\u003eCharge time depends on the charger's output. For a 300Ah battery, a charge rate around 30 to 45 amps balances speed and battery health, bringing the battery from empty to full in roughly 7 to 10 hours. A higher-output charger reduces that time.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"lbs-faq-item\"\u003e\n\u003cinput type=\"checkbox\" id=\"faq-12300-7\"\u003e \u003clabel for=\"faq-12300-7\"\u003eHow do I install and torque the terminals?\u003c\/label\u003e\n\u003cdiv class=\"lbs-faq-answer\"\u003e\n\u003cp style=\"font-size: 18px;\"\u003eConnect to the marked positive and negative terminals, and never reverse polarity. Tighten the M8 stainless bolts to 10 ft-lbs with a torque wrench. Loose connections can overheat and damage the battery.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"lbs-faq-item\"\u003e\n\u003cinput type=\"checkbox\" id=\"faq-12300-8\"\u003e \u003clabel for=\"faq-12300-8\"\u003eWhat does the built-in heater do?\u003c\/label\u003e\n\u003cdiv class=\"lbs-faq-answer\"\u003e\n\u003cp style=\"font-size: 18px;\"\u003eWhen the battery reaches freezing temperature and a charger is connected, the heater warms the cells so the battery can charge safely. Charging a lithium battery below freezing without heating can damage the cells, so the heater allows cold-weather charging that a standard lithium battery cannot do.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"lbs-faq-item\"\u003e\n\u003cinput type=\"checkbox\" id=\"faq-12300-9\"\u003e \u003clabel for=\"faq-12300-9\"\u003eDo I need the heated version?\u003c\/label\u003e\n\u003cdiv class=\"lbs-faq-answer\"\u003e\n\u003cp style=\"font-size: 18px;\"\u003eThe heater matters if you charge the battery in freezing conditions, such as early-spring, late-fall, ice-season, or cold-climate use. If you only charge in above-freezing conditions, the heater is not required. The battery still discharges and powers your gear in cold weather down to -4°F.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"lbs-faq-item\"\u003e\n\u003cinput type=\"checkbox\" id=\"faq-12300-10\"\u003e \u003clabel for=\"faq-12300-10\"\u003eWhat is the difference between the Standard and Heated versions?\u003c\/label\u003e\n\u003cdiv class=\"lbs-faq-answer\"\u003e\n\u003cp style=\"font-size: 18px;\"\u003eThe Heated version adds a self-heating element that lets the battery charge in freezing conditions. Capacity, voltage, discharge specs, and dimensions are the same for both versions.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"lbs-faq-item\"\u003e\n\u003cinput type=\"checkbox\" id=\"faq-12300-11\"\u003e \u003clabel for=\"faq-12300-11\"\u003eIs it waterproof? Can it get wet?\u003c\/label\u003e\n\u003cdiv class=\"lbs-faq-answer\"\u003e\n\u003cp style=\"font-size: 18px;\"\u003eThe case is sealed and water-resistant and handles spray and accidental splashes, but it is not designed for submersion or sustained water exposure. Mount it in a sealed battery box or a dry, secure compartment for marine use. Water intrusion is not covered under warranty.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"lbs-faq-item\"\u003e\n\u003cinput type=\"checkbox\" id=\"faq-12300-12\"\u003e \u003clabel for=\"faq-12300-12\"\u003eHow do I check the real state of charge?\u003c\/label\u003e\n\u003cdiv class=\"lbs-faq-answer\"\u003e\n\u003cp style=\"font-size: 18px;\"\u003eUse the MillerTech Bluetooth app for accurate readings of charge, voltage, and current draw. A voltage-based meter can read the same value for much of the discharge because lithium holds a flat voltage curve, so the app gives a clearer picture. For the most accurate resting reading, check after the battery has sat without charging or load for about 15 minutes.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"lbs-faq-item\"\u003e\n\u003cinput type=\"checkbox\" id=\"faq-12300-13\"\u003e \u003clabel for=\"faq-12300-13\"\u003eWill it fit my existing battery tray?\u003c\/label\u003e\n\u003cdiv class=\"lbs-faq-answer\"\u003e\n\u003cp style=\"font-size: 18px;\"\u003eIt is a Group 50 battery measuring 13.5 in x 9.6 in x 10.5 in, which is larger than a standard Group 24, 27, or 31. A standard tray will not fit it. A tray sized for the 12V 300Ah footprint is available separately.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"lbs-faq-item\"\u003e\n\u003cinput type=\"checkbox\" id=\"faq-12300-14\"\u003e \u003clabel for=\"faq-12300-14\"\u003eHow much does it weigh compared with a lead-acid battery?\u003c\/label\u003e\n\u003cdiv class=\"lbs-faq-answer\"\u003e\n\u003cp style=\"font-size: 18px;\"\u003eIt weighs 62.3 lbs. Because lithium delivers close to its full rated capacity, one battery replaces a heavier bank of lead-acid batteries of similar usable capacity.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"lbs-faq-item\"\u003e\n\u003cinput type=\"checkbox\" id=\"faq-12300-15\"\u003e \u003clabel for=\"faq-12300-15\"\u003eCan I run it all the way down?\u003c\/label\u003e\n\u003cdiv class=\"lbs-faq-answer\"\u003e\n\u003cp style=\"font-size: 18px;\"\u003eLiFePO4 batteries can safely use most of their rated capacity, and the built-in BMS protects the cells with a low-voltage cutoff at 10V. This provides much more usable energy than a lead-acid battery, which should only be discharged about halfway.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"lbs-faq-item\"\u003e\n\u003cinput type=\"checkbox\" id=\"faq-12300-16\"\u003e \u003clabel for=\"faq-12300-16\"\u003eCan I use it as a starting or cranking battery?\u003c\/label\u003e\n\u003cdiv class=\"lbs-faq-answer\"\u003e\n\u003cp style=\"font-size: 18px;\"\u003eThis is a deep-cycle battery for house, electronics, and trolling power. It is not sold as a cranking or dual-purpose starting battery. If you need to start an engine, use a MillerTech battery rated for starting or dual-purpose use.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"lbs-faq-item\"\u003e\n\u003cinput type=\"checkbox\" id=\"faq-12300-17\"\u003e \u003clabel for=\"faq-12300-17\"\u003eWhat does the warranty cover?\u003c\/label\u003e\n\u003cdiv class=\"lbs-faq-answer\"\u003e\n\u003cp style=\"font-size: 18px;\"\u003eIt carries a 10-year no-questions-asked warranty from MillerTech, with shipping for repair or replacement covered by the manufacturer during the warranty period. Damage from water intrusion is not covered, so use a sealed enclosure in marine settings.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cp\u003e \u003c\/p\u003e","brand":"Millertech","offers":[{"title":"Default Title","offer_id":48494288732418,"sku":"12300-BTH","price":1699.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0723\/3660\/5442\/files\/Millertech_12V_300Ah_Marine_Battery_Heated.webp?v=1789415911","url":"https:\/\/www.lithiumbatterysupply.com\/products\/millertech-12v-300ah-heated-marine-lithium-battery-bluetooth-lifepo4-deep-cycle","provider":"Lithium Battery Supply","version":"1.0","type":"link"}