12V-class lithium titanate module
−40 to 65 °C
6C can charge to full in 10 minutes
25,000 cycles
A 12 V battery built to last decades.
Six 40 Ah LTO cells, a 5 A active balancer and brushed-aluminum M12 terminals in a 10 × 6.5 × 9 in package. Built for auxiliary power, off-grid systems and motive use.
$999 single · $899 each for 2+ · 20-year limited warranty
At a Glance
- Capacity
- 40 Ah
- Nominal Voltage
- 13.8 V
- Continuous Rate
- 240 A (6C)
- Cycle Life
- ~25,000 cycles
- Operating Temp
- −40 to 65 °C
- Warranty
- 20-year limited
Why LTO
The Battery That Outlasts the Vehicle.
Lithium titanate trades a little energy density for a lot of everything else: cycle life measured in tens of thousands, high charge and discharge rates, and operation from −40 °C. No acid, no watering, no corrosion checks.
| Xirsix LTO Module | Typical Lead-Acid (SLA/AGM) | |
|---|---|---|
| Cycle Life | ~25,000 cycles to 80% | 200–500 cycles (deep discharge) |
| Calendar Life | Up to 25 years with proper use | 3–5 years |
| Operating Temperature | −40 to +65 °C | Struggles below 0 °C or above 40 °C |
| Charge Rate | Up to 6C continuous | 0.2–0.5C recommended |
| Maintenance | None | Watering, cleaning, corrosion checks |
Source: Xirsix LTO vs. lead-acid comparison and module datasheet XIR-DS-MOD6S40-001 Rev A.
Cost over time
Count the Replacements.
Lead-acid costs less on day one. Put in your own numbers to compare what each costs over the years you’ll run it.
Inside the module
Simple by Design.
Six 40 Ah LTO Cells, 6S1P
Cylindrical lithium titanate cells in series for 13.8 V nominal.
5 A Active Capacitive Balancer
Keeps the cells equalized automatically during charging.
Brushed-Aluminum M12 Terminals
Nord-Lock washers and 6061 aluminum automotive post adapters included. 10 Nm max torque.
PETG Enclosure
Water-resistant, not waterproof. Good resistance to common automotive fluids.
No Traditional BMS, by Design
A BMS’s MOSFET switches and shunts would add resistance and cap the current, so we leave them out to keep the cells’ full high-current capability; the 5 A active balancer still keeps the cells matched. Like the lead-acid battery it replaces, protection comes from your system: properly sized cable, external fusing, and 9.0–17.4 V.
Specifications
The Numbers.
Electrical
- Configuration
- 6S1PSix LTO cells in series
- Rated Capacity
- 40 AhAt 25 °C, standard discharge
- Energy
- 500 WhConservative rating
- Nominal Voltage
- 13.8 V6 × 2.3 V per cell
- Ideal Operating Range
- 11–15 VBest performance and longevity
- Maximum Voltage
- 17.4 V6 × 2.9 V charge cut-off. Do not exceed.
- Minimum Voltage
- 9.0 V6 × 1.5 V discharge cut-off. Do not go below.
- Continuous Charge / Discharge
- 240 A (6C)Per module design rating. Monitor temperature.
- Peak / Pulse
- ~10C for 10 s
- Internal Resistance
- ≤ ~4–5 mΩApproximate, module
- Balancing
- 5 A active capacitiveIntegrated; equalizes cells automatically
- Built-In Protection
- None, by design (no traditional BMS)A BMS's switches and shunts would add resistance and cap current. Use external fusing and stay within 9.0–17.4 V.
Life
- Cycle Life
- ~25,000 cyclesTo ≥ 80% capacity, standard test conditions
- Calendar Life
- Up to 25 yearsWith proper care (SOC, temperature, minimal abuse)
Charging
- Compatible Chargers
- Standard 12 V lead-acid or Li-ionMay not reach full 17.4 V; normal and safe
- Recommended Charge Voltage
- ~14.4–15.0 VAvoid constant high-voltage float
- Alternators
- Standard 12 V automotiveFully compatible
Environment
- Operating Temperature
- −40 to +65 °CCell spec; ≤ 1C below 0 °C; cool above 35–40 °C
- Water Resistance
- Water-resistant, not waterproofSplash and light rain; no submersion or pressure washing
- Enclosure Temperature
- ~60–70 °C continuousPETG softens near 75–85 °C
Mechanical
- Dimensions
- 10 × 6.5 × 9 in~254 × 165 × 229 mm (DERIVED)
- Weight
- 22 lb (~10.0 kg)
- Enclosure
- PETG housingImpact- and chemical-resistant, serviceable. White sleeve, black caps and base.
- Terminals
- M12 × 1.75 posts, brushed aluminumNord-Lock washers and automotive post adapters included
- Terminal Torque
- 10 Nm maxDo not exceed; use a calibrated torque wrench
Shipping and warranty
- Shipping Class
- UN3480, Class 9Lithium-ion batteries; ground shipping
- Warranty
- 20-year limitedRepair or replace; see warranty for terms
Downloads
- Datasheet (From Live Specs)Open
- Limited Warranty XIR-WAR-MOD6S40-001 Rev ARead
- Install Guide and SDS PDFsOn Request
Fleet & government
Buying for a Fleet or an Agency?
Trucks, heavy equipment, emergency and municipal vehicles. Tell us what you run and how many, and we'll come back with a quote. Purchase orders welcome.
- — Quantity pricing from 2 units
- — Install guidance and torque specs with every module
- — 20-year limited warranty
Questions
Before You Buy.
Can a Xirsix module replace my 12-volt battery?+
In most 12V-class systems, yes. Nominal voltage is 13.8 V with an ideal operating range of 11-15 V. For a single-battery vehicle or boat, swap it in place of the existing battery. In multi-battery systems (golf carts, RVs, off-grid and solar banks), don't mix Xirsix modules with other battery types: replace the whole bank. There's no traditional BMS by design (it would limit current), so fuse it and keep it between 9.0 V and 17.4 V.
Do I need a special charger?+
No. Standard 12 V lead-acid and lithium-ion chargers, and standard 12 V automotive alternators, are compatible. A standard charger may not take the module all the way to 17.4 V, which is normal and safe. For best results use a charger that reaches about 14.4-15.0 V, and avoid constant high-voltage float.
How fast can it charge?+
The module is rated for 6C (240 A) continuous charge and discharge, so at full rate a charge from empty takes on the order of 10 minutes. In practice the charger sets the pace: most lead-acid chargers supply far less current than the module can accept.
What does the 20-year warranty cover?+
Repair or replacement for qualifying failures under normal use for twenty years from the original purchase date, including capacity below 80% of the rated 40 Ah under standard test conditions. Normal LTO aging and high-cycle fade aren't defects. Claims go through support@xirsix.com. The warranty document has the full terms.
