36V 40Ah
Lithium Deep Cycle Battery
Group 31


36V 40Ah
Lithium Deep Cycle Battery
Group 31

Fish all day with 36V lithium power! The RB36V40 is a durable and long-lasting 36V lithium iron phosphate power source designed specifically for marine use. The parallel design brings a simpler set-up and more capacity, keeping you out on the water for longer.



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Simpler Set-Up

Get max voltage with minimum hassle thanks to the RB36V40’s parallel set-up. The improved connectors and small footprint make on-board installation a breeze, while the battery’s low weight means you’ll never sacrifice speed through the water.

Longer Lasting

The parallel set-up means quicker and easier charging, but it also means there’s more in the tank when you need it. The RB36V40 offers 20% greater capacity than its series equivalent*, translating to enhanced run times to keep you out on the water for longer. *Based on 3 @ 40Ah in parallel vs 3 @ 12V 100Ah in series


The RB36V40 is built for the marine environment. You'll get year-round peace of mind with the newly enhanced case, featuring an IP67 waterproof rating, and a new glue channel and screw-latched enclosure to protect against airborne contaminants.

Suitable For Commercial Use

The benefits of parallel power translate equally well to various commercial applications. For example, the battery’s increased capacity, faster charge time, and reduced downtime and maintenance costs make it ideal for use in floor cleaning settings.




Nominal Voltage 38.4 V
Nominal Capacity 40 Ah
Capacity @ 25 A 96 min
Resistance ≤50 mΩ @ 50% SOC
Efficiency 99%
Self Discharge <3% per Month
Series Connections No. 36V system only.
Parallel Connections Unlimited


Maximum Continuous Discharge Current 50 A
Peak Discharge Current 175 A (7.5 s ±2.5 s)
Discharge Over-Current Protection 200A +/- 35A (100 +/- 50ms )
Recommended Low Voltage Disconnect 30.0 V
Discharge Under-Voltage Protection 27.6 V (2.3 ±0.01 vpc)
Reconnect Voltage 30.0 V (2.5 ±0.08 vpc)
Short Circuit Protection Response Time 200-800 μs


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)
High Temperature Cut-Off 167 oF (75 oC)
Reconnect Temperature 149 oF (65 oC)


Dimensions (L x W x H) 13 x 6.8 x 8.4”329 x 172 x 214.7 mm
Weight 30.9 lbs (14 kg)
Terminal Type M8 x 1.25 x 12 mm
Terminal Torque 80 - 100 in-lbs (9 - 11 N-m)
Case Material ABS & PC blend (UL94-V0 flame rating)
Enclosure Protection (Waterpoof Rating) IP67
Cell Type - Chemistry Cylindrical - LiFePO4


Recommended Charge Current 4 A – 20 A
Maximum Continuous Charge Current 40 A
Charge Current 14 to 32 oF (-10 to 0 oC) ≤0.1 C (4 A)
Charge Current -4 to 14 oF (-20 to -10 oC) ≤0.05 C (2 A)
Recommended Charge Voltage 42.6 V - 43.8 V
BMS Charge Voltage Cut-Off 46.2 V (3.85 ±0.025 vpc)
Reconnect Voltage 43.8 V (3.65 ±0.05 vpc)
Balancing Voltage 41.7 V (3.475 vpc)


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


Soc Charagteristics 36 V graph
Discharge Voltage Temp 36 V graph
Discharge Voltage Rates 36 V graph
Charge Voltage Rates 36 V graph
Cycle Life Vs Depth Discharge Chart graph
Life Vs Lead Acid Chart graph


Frequently Asked Questions

Can I use my existing lead-acid battery charger (Wet, AGM or Gel) to charge RELiON lithium iron phosphate batteries?
Most likely, yes. Our lithium batteries are very charger-friendly. Most chargers today have a lithium charge profile, which is what we recommend using. AGM or gel charge profile chargers will work with our batteries. We do not recommend the use of a flooded charge profile with our 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 our Lithium Charging Instructions for more details.
How long will it take to charge a LiFePO4 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.

The RB36V40 Is Great For Powering

Anchor V2 230216 114031


Commercial 230216 114024

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