The Pylontech RT12100G31 is a 12V 100Ah lithium iron phosphate (LiFePO4) battery from the RT Series, built as a direct, drop-in upgrade for lead-acid batteries in off-grid solar, leisure, marine and backup power systems. With a fully sealed IP67 enclosure and a built-in heating film for reliable cold-weather charging, it is engineered to keep working through the conditions that stop a standard lithium battery cold.
An intelligent Battery Management System (BMS) manages charge, discharge and cell balancing automatically, while auto-balancing across parallel units and series connection of up to 4 batteries make it straightforward to scale a 12V, 24V or 48V bank without the state-of-charge mismatches that plague older lead-acid setups.
Good to Know
This is the heated variant of Pylontech's 12V RT Series — a built-in heating film allows the battery to warm itself for charging in temperatures down to −40°C, making it far better suited to UK winters, unheated outbuildings and vehicle installations than a standard LiFePO4 battery without heating.
Key Features
Built-in heating film
An internal heating film allows the battery to be warmed for charging in ambient temperatures as low as −40°C, controlled automatically via the dry contact heater terminal on the master battery.
Intelligent BMS protection
The onboard Battery Management System provides comprehensive protection against overcharge, over-discharge, over-current and short-circuit conditions, and manages cell balancing and charge/discharge automatically.
Auto-balancing in parallel
Multiple RT12100G31 units can be connected in parallel without internal state-of-charge mismatches, thanks to Pylontech's active balancing strategy.
Series & parallel expansion
Supports up to 4 batteries in series (for 24V or 48V systems) and multiple strings in parallel, up to a maximum of 16 modules in a single bank.
Multi-protocol communication
Built-in CAN (500Kbps), RS485 (115200bps) and Bluetooth (BLE5.0) connectivity, plus 2 dry contact inputs and outputs, for monitoring and integration with compatible inverters and charge controllers.
IP67 sealed construction
A fully sealed IP67-rated enclosure protects against dust and water ingress, suiting marine, exterior and enclosure-free installations that a standard indoor battery could not tolerate.
Why Choose This Over Lead-Acid
More usable capacity
LiFePO4 chemistry allows a much deeper safe discharge than lead-acid, giving significantly more usable energy from the same rated capacity without shortening battery life.
Far longer cycle life
Rated for more than 4,500 charge cycles at 25°C with a 10-year design life, comfortably outlasting the few hundred cycles typical of an equivalent AGM or gel battery.
Lighter, more compact power
At 12kg for 100Ah, it is dramatically lighter than a lead-acid battery of comparable capacity — a meaningful advantage in vehicles, boats and wall-mounted enclosures.
Zero maintenance
There is no topping up, no equalisation charging and no acid to manage — the sealed maintenance-free design is ready to install and forget.
Suitable For
- Off-grid and hybrid solar energy storage systems
- Caravans, motorhomes and campervan leisure battery banks
- Marine and boat house battery systems (IP67-rated for exposed installation)
- Backup and UPS power for critical loads
- Direct lead-acid replacement in 12V, 24V or 48V series/parallel configurations
Technical Specifications
Electrical
Chemistry
LiFePO4 (Lithium Iron Phosphate)
Working voltage range
10.8V – 14.4V
Recommended charge voltage
14V – 14.4V
Internal resistance
<20mΩ
Recommended charge/discharge current
50A
Max. continuous charge/discharge current
100A
Peak discharge current
200A for 30 seconds
Cycle life
>4,500 cycles @ 25°C
Physical & Environmental
Dimensions (L × W × H)
325 × 173.5 × 226mm
Charge working temperature
0°C to 60°C
Discharge working temperature
−20°C to 60°C
Heater-assisted working temperature
−40°C to 60°C (heating film active −40°C to −20°C)
Humidity
5–95% RH, non-condensing
Connectivity & System
Communication
CAN 500Kbps, RS485 115200bps, Bluetooth BLE5.0
Dry contact
2 inputs, 2 outputs (heater enable, charge/discharge control)
Series connection
Up to 4 units (12V/24V/36V/48V configurations)
Parallel connection
Up to 4 units per string
Max. modules supported
16 units total (4S4P or equivalent)
Short-circuit protection
<1kA, 100µs response
Certification
IEC62619, UL1973, FCC, CE, ROHS, Bluetooth SIG, UN38.3
Frequently Asked Questions
Can this battery charge in freezing temperatures?
Yes, within limits. The RT12100G31 can charge between 0°C and 60°C under normal operation. Between −40°C and −20°C, the built-in heating film activates to warm the cells, but the battery cannot charge or discharge during that heating period — it must reach 0°C before charging resumes.
How many of these batteries can I connect together?
Up to 4 units in series (for 24V, 36V or 48V systems) and 4 units in parallel per string, to a system maximum of 16 modules. Auto-balancing keeps parallel-connected units in step without manual intervention.
Does it need to communicate with my inverter to work?
No. The RT12100G31 will function as a standalone drop-in lead-acid replacement without any data connection, as long as your charging equipment is set to compatible voltages. CAN, RS485 and Bluetooth are available for systems that support monitoring and integration.
Is it safe to install outdoors or in a boat?
Yes — the IP67-rated enclosure is sealed against dust and water ingress, making it suitable for marine, exterior and enclosure-free locations where a standard indoor lithium battery would not be appropriate.
What happens if the battery fully discharges?
The battery should be recharged within 12 hours of a full discharge to avoid entering sleep mode. If left for long-term storage, it should be charged to above 90% state of charge every 6 months to maintain long-term health.
Can I mix this with lead-acid batteries in the same bank?
No. Pylontech batteries must only be connected with other batteries of the same type — mixing chemistries in a single bank is not supported and can damage both battery types.
