BMS selection: protection module or management board?
Choosing a battery management board is choosing how much supervision a pack gets. This guide explains the levels, the series counts and the questions that determine the right board — in general terms, without promising a specific protection parameter for any board.
Layered pack cross-section — the site's recurring diagram motif. It is a schematic, not a photograph of a product, factory or customer project, and it is not presented as a photograph of this company's factory.
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Start with the distinction between a protection circuit module and a management system. A protection module watches voltage and current and interrupts the circuit when a limit is crossed; it suits small packs where the main risks are overcharge, over-discharge and short circuit. A management system adds cell balancing — keeping series cells at equal charge — temperature sensing, and often communication about the pack's state; it suits larger packs where imbalance and heat matter as much as voltage. The company range on this site lists both levels: PCM boards for 1, 3, 4 and 6 series packs, and a 4-series BMS for 14.8V Li-ion packs supporting up to 10A discharge current, as listed.
Series count is the first selection fact. A single-cell pack needs a single-cell board at 3.6V. A three-series pack needs a three-series board at 11.1V. A four-series pack needs a four-series board at 14.8V. A six-series pack needs a six-series board at 21.6V. Those are the listed boards on this site, and the wider range covers other voltages, currents and configurations for specific project requirements, as the company category page states. A board for the wrong series count is not a board at all: it will either fail to protect or refuse to operate, and no adjustment on the buyer's side corrects it.
Current rating is the second selection fact. The board's discharge current rating must cover the pack's maximum continuous discharge current with margin, and its charge current rating must cover the charger's current. The listed 4-series BMS at up to 10A illustrates the point: a pack whose peak draw exceeds the board's rating will trip the board under load, behaving as if the battery were empty. A buyer should therefore state the pack's peak and continuous currents with the inquiry, not just its voltage and capacity.
Temperature, balancing and communication are the third group of facts. Temperature sensing matters where the pack runs warm, charges fast or operates outdoors; balancing matters where series cells must stay equal over hundreds of cycles; communication matters where the device or the site must know the pack's state without removing it. Each adds cost and complexity, and each should be specified only where the application needs it. A buyer who specifies every feature for a simple pack overpays; a buyer who omits balancing from a large series pack under-protects it. The custom BMS solution page on this site describes how a board requirement is developed for a specific pack, starting from these facts.
Questions to ask before you order
- How many cells in series, and at what nominal voltage?
- What are the pack's peak and continuous discharge currents?
- Is cell balancing needed, and is temperature sensing needed?
- Must the pack report its state to the device or the site?
- What board specification sheet applies to the exact board and pack?
Related pages
BMS boards · Custom BMS solution · Pack with built-in PCM · 48V selection
How to place an inquiry, step by step
- Send the device facts. Tell us the device type, the available space (length, width and maximum thickness), the nominal voltage you need, the capacity or runtime you target, and the peak current if your device has motors, radios or heaters.
- Name the model or the chemistry. If a page on this site matches, quote its model description and listing details. If nothing matches, say so and describe the chemistry and voltage you need, so the conversation starts on the custom route.
- Confirm documents and terms in writing. Ask for the certificate set for that exact model, confirm the minimum order, the price basis and the lead time for that listing, and confirm payment and warranty terms before you pay. Terms stated for one model listing do not transfer to another model.
- Agree the sample step. Confirm whether the next step is a listed sample, an engineering sample for a custom design, or a small trial order, and what test you will run on arrival — fit in the enclosure, runtime, or peak-current behaviour.
Send all of this in one message through the contact page: device type, space, voltage, capacity, peak current, model description if you have one, and the documents you need. That is the whole inquiry — no separate form, no account, no extra step.
What to send us now
Send one message with your device type, the space the pack must fit, the voltage and capacity you need, the peak current if it matters, and the model description if a page on this site already matches. Add the documents you need — certificates are available upon request — and whether you need a listed model or a custom design. Use the contact page or write to [email protected], or call +86-755-25629920. A specific message like that is what turns a range of hundreds of models into a short, answerable question.