XJ-D549: High-Power 8S BMS for Automotive Start and General Battery Applications
As lithium battery technology continues to expand across mobility and energy sectors, system designers demand protection boards that deliverhigher current capacity, greater flexibility, and compact design — without compromising safety.
To meet these requirements, XJ-BMS has developed the XJ-D549, a next-generation 8S Battery Management System(Bms) engineered for both general-purpose applications and automotive start protection systems.
Overview of XJ-D549
The XJ-D549 is a high-current, compact BMS board designed for 8-series battery configurations. It supports 150A, 200A, and 250A continuous discharge, and is compatible with multiple battery chemistries including:
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LFP (LiFePO₄)
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NMC (Lithium-ion)
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SIB (Sodium-ion)
This makes it a universal protection solution suitable for a wide range of lithium battery projects.
Automotive Start Protection Capability
Beyond standard BMS functionality, the XJ-D549 can also be configured as a vehicle start protection board, delivering exceptional peak current performance.
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Peak Current: Up to 2000A
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Recommended Safe Limit: Below 1900A (for stability and safety)
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Peak Duration: Configurable (factory-set delay time)
This design ensures reliable performance in high-surge automotive start systems, while maintaining protection against short-circuit and overcurrent events.
Important note:
The peak current and delay time parameters are custom-configurable by XJ-BMS engineers only.
To guarantee product safety and stability, customers cannot modify these settings independently.
| Item (the spec of XJ-D549 8S 200A) | Min | Typical | Max | Unit |
| Battery pack charging voltage | 28.8 | V | ||
| Charging MOS withstand voltage | 100 | V | ||
| Discharging MOS withstand voltage | 100 | V | ||
| Single cell overcharge detection voltage | 3.625 | 3.65 | 3.675 | V |
| Overcharge recovery voltage | 3.5 | 3.55 | 3.6 | V |
| Overcharge detection delay | 500 | 1000 | 1500 | mS |
| Single cell over-discharge detection voltage | 2 | 2.1 | 2.2 | V |
| Over-discharge recovery voltage | 2.6 | 2.7 | 2.8 | V |
| Over-discharge detection delay | 500 | 1000 | 1500 | mS |
| Battery pack continuous discharge current | 200 | A | ||
| Battery pack continuous charging current | 200 | A | ||
| Discharge overcurrent protection | 1900 | 2000 | 2100 | A |
| Overcurrent protection delay | 500 | 1000 | 1500 | mS |
| Self-consumption | 40 | uA | ||
| Battery equalization turn-on voltage | 3.475 | 3.5 | 3.525 | V |
| Battery equalization current | 30 | |||
| Charging high temperature protection temperature | 45 | |||
| Charging high temperature recovery temperature | 40 | |||
| Discharge high temperature protection temperature | 65 | 70 | 75 | ℃ |
| Discharge high temperature recovery temperature | 55 | 60 | 65 | ℃ |
| Charging low temperature protection temperature | -5 | 0 | 5 | ℃ |
| Charging low temperature recovery temperature | 0 | |||
| Discharge low temperature protection temperature | -25 | |||
| Discharge low temperature recovery temperature | -20 | |||
| Temperature protection delay | 3 | S | ||
| Output short circuit/over-discharge/overcurrent protection recovery | Automatic recovery after removing load following short circuit/over-discharge/over-current protection | |||
| Short circuit protection delay | 160 | 300 | 600 | uS |
| Normal operating state B-to-P- internal resistance | 30 | mΩ | ||
| Continuous 200A output current maximum temperature rise | 45 | ℃ | ||
Key Advantages
✅ High Peak Current Capability – Supports up to 2000A for engine start or heavy-duty applications.
✅ Adjustable Peak Delay Time – Factory-set based on customer requirements for surge control.
✅ Universal Compatibility – Works with LFP (LifePO4) , NMC (Li-ion) , and SIB (Sodium-ion / Na-ion) batteries.
✅ Lightweight and Slim Design – Ideal for compact battery packs and space-limited installations
✅ Dual Functionality – Serves as both standard protection hardware and automotive start BMS
Compact Power, Built for Innovation
The XJ-D549 stands out for its lightweight and ultra-thin design, making it particularly suitable for tight battery enclosures where every millimeter matters.
Despite its smaller footprint, it provides exceptional current handling and robust safety protection — combining performance and practicality in one board.
Applications
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Motorcycles starting
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Yacht starting or energy storage
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Automotive car starting
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Industrial lithium battery modules
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Custom OEM battery solutions requiring high current and reliability
Why Choose XJ-BMS XJ-D549
With a strong focus on innovation and engineering precision, XJ-BMS ensures every D549 board is thoroughly tested and factory-calibrated to deliver safe, stable, and reliable performance under demanding conditions.
Whether used in automotive start systems or general energy storage, the XJ-D549 provides the balance of power, protection, and compact design that modern lithium solutions demand.
XJ-BMS More Starting/Cranking BMS
| Model | Battery Series | Continuous Working Current Range | Peak Current | Size (mm) | Key Features |
|---|---|---|---|---|---|
| XJ-D426 | 4S | 100A/120A | 1000A | 145×65×13 | Balancing, NTC, over-charge protection, over-discharge protection, over-voltage protection, over-current protection, short-circuit protection. |
| XJ-D549 | 8S | 150A/200A/250A | 2000A | 208×85×4 | Balancing, NTC, over-charge protection, over-discharge protection, over-voltage protection, over-current protection, short-circuit protection. |
| XJ-D444 | 4S | 20A/30A/40A | 650A | 60×60×4 | Balancing, NTC, over-charge protection, over-discharge protection, over-voltage protection, over-current protection, short-circuit protection. |
Learn More
Looking for a compact yet powerful BMS that supports high peak current and custom configuration?
The XJ-D549 is your go-to solution.
Contact our technical team to discuss configuration options or integration support.
Visit our website: www.xj-bms.com