12V 20Ah
High Power Deep Cycle Lithium Battery


12V 20Ah
High Power Deep Cycle Lithium Battery

Estimated 1 - 2 weeks shipping.

The RB20-X is the smallest battery in the RELiON X-Series allowing for higher peak and higher continuous discharge currents compared to our standard lithium batteries. Ideal for solar and recreational power, this LiFePO4 battery is equipped with a flag terminal type and built-in BMS.

SAVE $29.19


MSRP: $291.95

United States Of America White 230216 103954


Warranty White 230216 103954


Free Delivery White 230216 103955



Maintenance Free

Plug, play, and charge. No watering, no corrosion.

Lightweight & Easy to Transport:

Compared to other battery chemistries, RELiON LiFePO4 batteries provide the same or greater energy at less than half the weight and size. This means more flexibility and ease of use!

Long Life

RELiON lithium batteries provide up to 10 times longer life than lead-acid batteries, and they still provide 80% of the rated capacity after 3,500 cycles.

Higher Power

Our X-Series batteries allow for higher peak and higher continuous discharge currents compared to our standard lithium batteries of the same size.

Fast Charging

RELiON lithium batteries charge much faster than traditional lead-acid batteries, and they’re packed with more usable energy and up to 10 times longer life so you’re always ready to go!

Partial State of Charge Tolerant

Partial charging does not affect performance quality or battery life. A low self-discharge rate means worry-free storage so even occasional users can be assured of reliable performance.

Constant Power

Full power available throughout discharge. Voltage does not drop like lead-acid.

Friendly & Safe

RELiON lithium batteries are the ultimate clean energy. No gassing, no fumes, and no pollution. Enjoy reliable power, while protecting the environment, using these non-hazardous batteries.



Electrical Specifications

Nominal Voltage 12.8 V
Nominal Capacity 20 Ah
Capacity @ 25 A 48 min
Energy 256 Wh
Resistance ≤60 mΩ @ 50% SOC
Efficiency 99%
Self Discharge <3% per Month
Maximum Batteries Connected in Series 3

Mechanical Specifications

Dimensions (L x W x H) 7.1 x 3.0 x 6.7” (181 x 76 x 169 mm)
Weight 6.1 lbs (2.75 kg)
Terminal Type M6
Terminal Torque 35 - 44 in-lbs (5 - 5 N-m)
Case Material ABS
Enclosure Protection IP66
Cell Type - Chemistry Cylindrical - LiFePO4

Discharge Specifications

Maximum Continuous Discharge Current 50 A
Peak Discharge Current 90 A (4 s ±1 s)
Discharge Over-Current Protection 140 A ±20 A (12 ±5 ms)
Recommended Low Voltage Disconnect 11.0 V
Discharge Under-Voltage Protection 8.0 V (2.0 ±0.08 vpc) (20 ±5 ms)
Reconnect Voltage 9.0 V ±1.32 V (2.25 ±0.33 vpc)
Short Circuit Protection Response Time 200-600 µs

Charge Specifications

Recommended Charge Current 1 A - 10 A
Maximum Continuous Charge Current 50 A
Charge Current 32ºF to 14ºF (-10 to 0ºC) ≤0.1 C (5 A)
Charge Current -4ºF to 14ºF (-20 to -10ºC) ≤0.05 C (2.5 A)
Recommended Charge Voltage 14.2 V - 14.6 V
BMS Charge Voltage Cut-Off 15.6 V (3.9 ±0.025 vpc)
(1.0 ±0.5 s)
Reconnect Voltage 15.2 V (3.8 ±0.050 vpc)
Balancing Voltage 14.4 V (3.6 ±0.025 vpc)

Temperature Specifications

Discharge Temperature -4 to 140 ºF (-20 to 60 ºC)
Charge Temperature* -4 to 113 ºF (-20 to 45 ºC)
Recommended Storage Temperature 23 to 95 ºF (-5 to 35 ºC)
BMS High Temperature Cut-Off 167 ºF (75 ºC)
Reconnect Temperature 122 ºF (50 ºC)
*Refer to charge currents below 0°C (32°F)

Compliance Specifications

Certifications CE & UKCA (battery)
UN38.3 (battery)
UL1642 (cells) (File# MH62098)
IEC62133 (cells)
Shipping Classification UN 3480, CLASS 9

Performance Characteristics

Charge Voltage Char Chart 12 V graph
Charge Voltage Soc Chart 12 V graph
Discharge Voltage At Various Rates 12 V graph
Discharge Voltage Chart 12 V graph


Robert C.

I did my research and found that Relion was one of the top lithium Ion Phosphate battery suppliers .I chose this particular model because it had the 22 Amp continuous output that I needed to power my amateur radio gear. After using it a few times in the portable field and using my portable solar charge controller This battery is everything I thought it would be and any future batteries will also be Relion.

The RB20-X Is Great For Powering

Solar 230216 114023

Renewable Energy

Understanding Battery Terms

Understanding the basics of battery ratings and terminology is important when comparing and selecting the right type and number of batteries for your application to ensure you have enough energy to meet your energy goals.

Learn More About Battery Terms

We're Invested In Our Lithium Iron Phosphate Batteries

Lithium Certifications Recycling 1000X300