300Ah 12V Lithium Battery Group 8D RB300

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The RELiON 12V 300Ah deep-cycle lithium battery is the perfect replacement for a group 8D sized battery. Weighing in at only 83 lbs it’s a relatively lightweight alternative to lead-acid and one of the most popular lithium batteries.

The RB300 surpasses expectation by being versatile, compact and more powerful than its lead-acid counterparts. It’s the perfect combination of size and capacity to fit many applications including, RV, marine, solar energy systems and more.

RELiON lithium iron phosphate (LiFePO4) batteries provide more energy for high consumption than traditional lead-acid batteries. They also offer fast charging and discharging, high efficiency and a longer cycle life – plus no maintenance!

Not all lithium batteries are created equal. All RELiON Batteries use the safest and most stable components, including a LiFePO4 cathode and a built-in Battery Management System (BMS). The BMS ensures a long lifetime, safe handling – and high-accuracy State of Charge (SOC) calculations.



  • 300 Ah
  • 3840 Wh
  • 12.8 V
  • Group 8D size
  • LiFePO4 battery chemistry
  • Built-in battery management system (BMS)

Wee Expert Tip - Use a Victron SmartShunt battery monitor to conveniently read out battery parameters, like state of charge, time to go, historical information and much more via a Bluetooth connection to the VictronConnect App on your phone (or tablet).



Can I use my existing lead-acid battery charger (Wet, AGM or Gel) to charge RELiON lithium iron phosphate batteries?
  • Most likely, yes. RELiON lithium batteries are very charger-friendly. Most chargers today have a lithium charge profile, which is what RELiON recommends using. AGM or gel charge profile chargers will work with RELiON batteries. RELiON does not recommend the use of a flooded charge profile with their batteries. These chargers may reach the overvoltage protection limit and disconnect. It won’t damage the battery but will likely result in charger faults. See RELiON's Lithium Charging Instructions for more details.

      How long will it take to charge a lithium battery?
      • Lithium iron phosphate batteries can be charged in as fast as 1 hour. We recommend using a rate that charges our batteries in 2-5 hours. Please refer to the data sheet for your particular model, to find the recommended charge rates. All of our data sheets are available on our website within the product section.


      Can the RB300 be wired in series or parallel?

      • Yes. The RB300 can be wired in series or parallel. The difference between parallel and series connections: Parallel connections involve connecting 2 or more batteries together to increase the capacity of the battery bank. In this case, the positive terminals are connected together and the negative terminals are connected together of all the batteries until you reach your desired capacity. Series connections involve connecting 2 or more batteries together to increase the voltage of the battery system. The positive of one battery is connected to the negative of another until the desired voltage is achieved. For example, if you connect 2 x 12V batteries in series, the battery system will be 24V.


      Is the RB300 a good battery replacement in sailboats?

      • Yes. The RB300 is a high power, reliable lead-acid alternative in sailboats and catamarans. The RB300 gives you the flexibility to replace several small, heavier lead-acid batteries in a single high capacity unit.





         Download Data Sheet



          Nominal Voltage 12.8 V
          Nominal Capacity 300 Ah
          Capacity @ 25A 720 min
          Energy 3840 Wh
          Resistance ≤ 30 mΩ @ 50% SOC
          Efficiency 99%
          Self Discharge <3% per Month
          Maximum Modules in Series 6


          Dimensions (L x W x H) 20.5 x 10.5 x 9.0” 520 x 267 x 228 mm
          Weight 83 lbs (37.5 kg)
          Terminal Type M8
          Terminal Torque 80 - 100 in-lbs (9 - 11 N-m)
          Case Material ABS
          Enclosure Protection IP56
          Cell Type - Chemistry Cylindrical - LiFePO4


          Maximum Continuous Discharge Current 100 A
          Peak Discharge Current 200 A (7.5 s ±2.5 s)
          BMS Discharge Current Cut-Off 280 A ±50 A (9 ±4 ms)
          Recommended Low Voltage Disconnect 11 V
          BMS Discharge Voltage Cut-Off 8 V (2.0 ±0.08 vpc) (140 ±60 ms)
          Reconnect Voltage 9.2 V (2.3 ±0.1 vpc)
          Short Circuit Protection 200-600 µs


          Recommended Charge Current 15 A - 50 A
          Maximum Charge Current 100 A
          Charge Current (0 to -10 ºC) ≤0.1 C
          Charge Current (-20 to -10 ºC) ≤0.05 C
          Recommended Charge Voltage 14.2 V - 14.6 V
          BMS Charge Voltage Cut-Off 15.6 V (3.9 ±0.025 vpc) (1.1 ±0.4 s)
          Reconnect Voltage 15.2 V (3.8 ±0.05 vpc)
          Balancing Voltage 14.4 V (3.6 ±0.025 vpc)


          Discharge Temperature -4 to 140 ºF (-20 to 60 ºC)
          Charge Temperature -4 to 113 ºF (-20 to 45 ºC)
          Storage Temperature 23 to 95 ºF (-5 to 35 ºC)
          BMS High Temperature Cut-Off 176 ºF (80 ºC)
          Reconnect Temperature 122 ºF (50 ºC)


          Certifications CE (battery), UN38.3 (battery), UL1642 & IEC62133 (cells)
          Shipping Classification UN 3480, CLASS 9


          Best Use Replacement for a Group 8D sized battery
          Battery Weight 83 lbs
          Warranty 10 year manufacturer's warranty period (first 36 months are free replacement or repair coverage)





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