Battery Management System (BMS) Design
Custom BMS design for lithium battery packs under 100 V, including high-current applications above 100 A in environments where failure is not acceptable.
A battery management system decides whether a pack is safe, how long it lasts and how much of its capacity you can actually use. We design custom BMS electronics and firmware, from single-cell protection to multi-cell packs with balancing, current measurement and state-of-charge and state-of-health estimation.
What this includes
- Custom BMS for lithium packs under 100 V
- High-current designs above 100 A
- Cell protection, balancing and fault handling
- State-of-charge and state-of-health estimation
- CAN, UART, I2C and SMBus communication
- Thermal design and validation at sustained load
High-current design that holds up
Above 100 A, a BMS is as much a thermal and layout problem as a circuit problem. We design the high-current path deliberately: MOSFET or contactor switching sized with real margin, copper weight and busbar choices, low-resistance current sensing, and thermal paths that keep components inside their ratings at sustained load rather than just at peak. Every high-current design is checked on real hardware at load, not signed off from calculations alone.
Protection, balancing and monitoring
We design cell protection for over-voltage, under-voltage, over-current, short circuit and temperature, with independent hardware protection where a firmware fault must not be able to cause an unsafe condition. Passive balancing keeps cells matched over the life of the pack, and state-of-charge and state-of-health estimation gives the product and the user an honest picture of remaining capacity.
Built for high-reliability environments
We have designed BMS for applications where a pack failure stops work or creates a safety risk. That shapes the design from the start: fault detection and logging, defined behaviour in every failure mode, conformal coating and connector choices for harsh environments, and test procedures that prove the protection works rather than assuming it does.
Integration with the rest of the product
A BMS has to talk to the product it powers. We integrate communication over CAN, UART, I2C or SMBus, charger control, and wake and sleep behaviour that keeps quiescent current low in storage. Because we also design the main electronics and firmware, the BMS and the product are designed together rather than bolted together.
Common questions
Should we use an off-the-shelf BMS or a custom one?
If an off-the-shelf BMS fits your pack, current, size and communication needs, use it, as it is cheaper and faster. A custom BMS makes sense when space, current, integration with your product, or reliability requirements rule the standard options out. We will tell you which side of that line you are on before you commit to a custom design.
What voltages and currents do you work with?
We work on packs under 100 V, which covers most portable, light mobility, tool and equipment applications, including high-current designs carrying over 100 A.
Can you help with battery safety and transport testing?
Yes. We design with the relevant safety and transport requirements in mind and support you through testing with accredited labs, so the design does not need reworking after a failed test.
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ISO 9001 certified electronics, firmware and mechanical engineering, from first prototype to small-batch manufacturing.
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