Price and schedule on a Battery Management System PCB copy come down to five things: layer count, how many cell channels the board monitors, whether the analog front end and MCU are still available parts, whether the board is coated or potted, and whether you need firmware and calibration data along with the copper. A 2-layer 4S protection board is a short job. A 16-channel daisy-chained pack controller with an isolated CAN interface and a locked MCU is not.
This page explains what moves the number in each direction, so you can look at your own board and estimate before you ask for a quote.
What actually drives the cost of a Battery Management System PCB copy
Two BMS boards of the same physical size can differ in price by a wide margin. The drivers, roughly in order of impact:
- Cell channel count. Each cell tap brings a divider or filter network, a bleed resistor, a balance switch, and a routed sense pair. Sixteen channels is sixteen repeats of that pattern to trace, verify, and cross-check against the AFE pinout.
- Layer count and stackup. A 2-layer board is imaged from both sides. A 4- or 6-layer board needs controlled delamination and separate imaging per copper layer, plus reconstruction of the internal ground and sense reference planes.
- The analog front end. A BQ769x0, LTC681x/68xx, or MAX17xxx-class AFE has a specific pin map you can verify against. A relabeled or house-marked front end means the pinout has to be established electrically, which takes real bench time.
- Power path hardware. Parallel protection MOSFETs, heavy copper pours, shunt resistors with Kelvin connections, and current-path geometry all have to be reproduced dimensionally, not approximated.
- Coating and potting. Conformal coat adds a controlled removal step. Full epoxy potting is a different job entirely and changes both cost and schedule.
- Deliverable set. Gerbers and a BOM cost less than Gerbers plus BOM plus a full schematic. Add assembled and tested boards and you are into a turnkey scope closer to what a PCB copy and manufacturing package includes.
- Firmware. Reading protected code out of the pack MCU is a separate line item with its own feasibility question, discussed further down.
We do not publish flat prices for BMS work because the same nominal description — “16S BMS board, 100 x 60 mm” — covers boards that differ by a factor of several in effort. Send photos and the chip markings and you get a real figure.
How long a BMS board takes, by class
The table below is a planning guide, not a commitment. Your quote will carry the actual date, and it depends on shop load and on what we find when the board arrives.
| Board class | Typical characteristics | Relative lead time |
|---|---|---|
| Small protection PCM | 2 layers, 3S–7S, single AFE plus dual MOSFETs, no MCU or a small 8-bit part | Shortest — a few working days for copper and BOM |
| Mid-tier pack BMS | 2–4 layers, 8S–16S, AFE plus MCU, balance resistors, UART or CAN, thermistor mux | Roughly a week to a week and a half for files |
| Multi-string / master-slave BMS | 4–6 layers, daisy-chained isoSPI or isolated CAN, digital isolators, contactor and precharge drivers | Meaningfully longer — often two weeks or more for schematic-level output |
| High-voltage ESS controller | 6+ layers, reinforced isolation barrier, insulation monitoring, current sensing with dedicated analog section | Longest; scoped case by case after inspection |
| Any of the above + firmware | Locked MCU, EEPROM calibration constants | Add a separate firmware track that runs in parallel |
Prototype fabrication and assembly sit on top of the file work. If you want boards in hand rather than just data, budget for fab and SMT after file release, plus component lead time on the AFE — those parts have been intermittently scarce, and a long-lead front end can dominate the whole schedule.
What happens to your board, in order
Nothing about this process is mysterious, so here is the actual sequence.
Intake and non-destructive capture
The board is photographed at high resolution on both sides, then scanned. Every component is logged with its marking, package, and measured value where the part is passive and accessible. Electrolytics and film caps get voltage and ripple ratings recorded, because a BMS sits across a pack and a substituted 25 V part where a 63 V part belonged is a field failure waiting to happen. Fine-pitch and bottom-terminated parts go under X-ray if the joint or the die pad matters.
Coating removal and layer separation
Conformal coat comes off in a controlled way, area by area, so silkscreen and test-point labels survive long enough to be recorded. Then the board is delaminated and each copper layer is imaged separately. On a 4-layer BMS this is where the plane structure gets recovered — specifically how the analog ground under the AFE relates to the power ground carrying pack current, and where the two are stitched. Get that wrong and the copy measures cell voltages with a noise floor the original never had.