LTO low voltage range problem and BMS adaptation method
31,Jul 2025
When working with lithium-ion battery packs, many people get confused between a Battery Management System (BMS) and a Battery Balancer. Are they the same thing? Should you install both? This guide breaks down their roles, key differences, and helps you determine when each is necessary — especially if you're building or sourcing lithium battery packs for EVs, e-bikes, or energy storage systems.
A Battery Management System (BMS) is the essential brain of any lithium battery pack. It monitors and controls critical parameters to ensure the safe and efficient operation of the battery. A quality BMS protects your pack from:
Overcharging and overdischarging
Overcurrent during charging/discharging
Overtemperature and undertemperature conditions
Short circuits
Beyond protection, smart BMS models also offer:
Real-time communication via CAN, UART, RS485, or Bluetooth
SOC estimation and fault diagnostics
Passive or active cell balancing
Remote monitoring via apps or software
✅ For industrial or high-capacity battery systems, a smart BMS is essential.
✅ Example: KURUI Smart BMS for 13S 48V Lithium Pack
A Battery Balancer is a simpler device designed specifically to equalize the voltage across all the individual cells or groups of cells in a lithium pack.
Unlike a full-featured BMS, a balancer doesn't offer protection or communication. Its sole purpose is to:
Transfer energy from higher voltage cells to lower ones (active balancing)
Discharge high cells via heat dissipation (passive balancing)
Some low-cost BMSs do not include balancing. In such cases, using an external battery balancer can help maintain battery health and extend cycle life.
| Feature | BMS | Battery Balancer |
|---|---|---|
| Main Role | Protection + Monitoring + Balancing (in some cases) | Only balances cell voltages |
| Safety Functions | ✅ Yes | ❌ No |
| Communication | ✅ Yes (CAN, UART etc.) | ❌ No |
| Integrated in Pack | ✅ Yes | ❌ Optional |
| Cost | Higher | Lower |
| Standalone Use | Yes | Usually as an add-on |
| Typical Use | EVs, ESS, e-bikes | DIY, low-cost BMS systems |
That depends on your system configuration.
Your BMS includes reliable passive or active balancing.
You’re using a commercial Smart BMS for an e-bike, golf cart, or energy storage unit.
You’re using a Standard BMS with no built-in balancing.
Your pack has significant cell drift and requires faster equalization.
You’re assembling a DIY battery pack using recycled or unmatched cells.
Balancers come in two main types: