48V Battery Systems for AGVs and Robotics: Sizing and Configuration

Quick answer: A 48V lithium battery pack for an AGV or industrial robot is built by picking a cylindrical NMC cell, stacking 13 or 14 of them in series to land in the 44-52V window the industry calls "48V," then adding enough parallel groups to cover both the target runtime and the continuous discharge current. From there, the pack's real continuous and peak current, not its voltage, decides the BMS current tier (60-80A, 100A, 150A, or 200A) and the connector (XT60, XT90, AS150U, or Harting MPC30/MPC60). Skipping that last step is the most common sizing mistake: a pack sized for capacity alone will trip its BMS or overheat its connector the first time the AGV accelerates hard or recovers from an obstacle stop.

This guide walks the full chain: series/parallel math for a real cell, continuous-versus-peak current sizing for AGV duty cycles, BMS tier selection, and connector matching. If you're starting further back, from picking a chemistry or comparing lead-acid to lithium in the first place, read the fundamentals of AGV battery pack sizing first; this post picks up where that one leaves off and goes deep on the 48V-specific configuration math.

Why 48V Is the Sweet Spot for AGVs and Industrial Robotics

Most AGVs and mobile robots in the 200-1,500 kg payload class draw somewhere between 1 and 5 kW at cruise, with short peaks well above that during acceleration or obstacle recovery. At that power range, 48V nominal is the point where current stays low enough for reasonable wire gauge and connector size, without pushing voltage high enough to trigger stricter electrical safety requirements that apply above roughly 60V DC on many industrial platforms.

The current-vs-voltage trade-off at real AGV power levels

Power, current, and voltage are linked by P = I × V. A drive system pulling 3 kW at 24V nominal draws around 125A. The same 3kW load at 48V nominal draws around 62.5A, half the current for the same power. That's the entire argument for 48V over 24V on anything above a small differential-drive AMR: less current means thinner cabling, lower resistive losses, and connectors and contactors rated for a more manageable current class.

Wiring and connector sizing implications

Halving the current at a given power level doesn't just save copper. It also changes which connector class fits. A 24V pack pulling 125A needs a connector and busbar sized for that current continuously; the 48V equivalent at 62.5A can often step down a full connector tier, for example from a heavy industrial connector to something in the XT90 or AS150U class. The connector-matching section below walks through this directly.

Motor-controller input-voltage compatibility

Before locking in a cell count, check the actual motor controller's input-voltage window, not just its "48V" label. Most 48V-class AGV motor controllers spec an absolute maximum input somewhere between roughly 58V and 63V, since they need headroom above nominal for a fully charged pack. A 14S pack of a cell that charges to 4.2V per cell reaches 58.8V at full charge, which is inside a typical 58-63V window but close enough to the edge that it needs verifying against the specific controller's datasheet, not assumed.

Configuring a Real 48V Pack: Series/Parallel Math for Cylindrical Cells

"48V" is a system class name, not a literal voltage. It covers packs that land anywhere from roughly 44V to 52V nominal depending on the cell chemistry and series count, the same way a "12V" car battery reads closer to 12.6V at rest. Two series counts routinely get sold as "48V" packs: 13S and 14S.

Why 13S and 14S both land near 48V nominal, and why the choice isn't arbitrary

Take a mid-range cylindrical NMC cell like the Amprius SA17, a 21700 cell with 3.60V nominal voltage, 4.20V full-charge voltage, and a 2.75V discharge cutoff (per its datasheet's cycle-life test window). Stack 13 in series and the pack sits at 46.8V nominal. Stack 14 and it sits at 50.4V nominal, exactly one cell's nominal voltage higher. Both fall inside the 44-52V band the market treats as "48V class," and both will run on the same motor controllers rated for that class.

The real decision isn't "which one is 48V." Both are. It's a trade-off between three things: how close the pack's full-charge voltage sits to the motor controller's absolute maximum input (14S runs closer to that ceiling), how many parallel groups are needed to hit a target capacity or current at a given series count (higher series count needs fewer parallel groups for the same power, since current drops as voltage rises), and which off-the-shelf chargers and BMS boards are readily available at each series count. There's no universally "correct" answer; it's a system-level call made once the controller and charger are picked, not before.

Worked example: nominal, min, and max pack voltage for 13S vs 14S

Using the Amprius SA17 (21700 cylindrical, 3.60V nominal, 4.20V charge, 2.75V cutoff) as the worked cell:

The 3.6V gap between the two nominal voltages is exactly one cell's nominal voltage, since the only difference between the rows is a single added cell in series. The practical question this table answers: if a motor controller's absolute max input is spec'd at 56V, the 14S pack's 58.8V full-charge voltage is out of range and 13S is the only option, regardless of which configuration would otherwise be preferred for current or parallel-group count.

Parallel groups: sizing for capacity and current, not just voltage

Series count sets voltage. Parallel count sets capacity and shares out current. A single Amprius SA17 delivers 6.0Ah typical capacity and 18A continuous discharge (3C). Put four in parallel (a 13S4P pack) and the group delivers 24Ah, roughly 1.12 kWh at 46.8V nominal, with 72A continuous and up to 120A pulse discharge available from the cells themselves.

That 72A/120A cell-level ceiling is a starting point, not the final number. It has to be checked against the AGV's actual continuous and peak current draw (next section), and it sets a floor under how big the BMS and connector need to be: no BMS or connector downstream of this pack should be rated below what the cells themselves can deliver, or the cells become the constraint on paper while the electronics become the constraint in practice.

Cell choice at this stage is also a rotation, not a fixed answer. A Reliance RS60 (21700 cylindrical, 302 Wh/kg, 50A continuous / 80A pulse per cell) trades some energy density for much higher per-cell current, useful when the AGV's duty cycle is current-heavy rather than runtime-heavy. A Molicel M65A (21700 cylindrical, 322 Wh/kg) leans the other way, toward energy density over raw current. And for programs with an existing cell-supply relationship or a qualified cell already in another product line, customer-supplied cells are a real option: Dan-Tech will build the pack, BMS, and mechanical/thermal design around a cell the customer already sources, as long as it has verifiable spec data to design against.

Continuous vs Peak Current Sizing for AGV Duty Cycles

Every AGV duty cycle has at least two current profiles that matter, and sizing for only one is where most undersized packs come from.

Sustained drive current vs acceleration/obstacle-recovery peaks

Sustained drive current is what the pack delivers at cruise, moving at a steady speed on a flat floor. It's the number most sizing guides stop at. But AGVs accelerate from a stop at every waypoint, climb ramps, and recover from obstacle-triggered stops by re-accelerating, often multiple times a minute on a busy floor. Those events pull 1.5 to 2.5 times the sustained current for a few seconds at a time. A pack sized only for the sustained number will ask its BMS to either throttle power during exactly the moments the AGV needs it most, or trip a protection fault mid-cycle. The fix is sizing the BMS current tier (below) to the peak current profile, not the average one.

Docking and opportunity-charging current

Charge-side sizing gets skipped almost as often as peak-discharge sizing. AGVs that use opportunity charging, topping up at a dock between runs rather than a full overnight charge, need the pack to accept a meaningfully higher charge current than a pack that only ever gets an overnight trickle charge. The Amprius SA17 used in the worked example above accepts 3A typical (0.5C) and 6A max (1C) per cell; a 13S4P pack of that cell can accept up to 24A at the pack level. If the target dock time calls for a faster top-up than that supports, the fix is either a higher charge-rate cell or accepting a longer dock cycle, decided before the pack is built, not discovered after.

Ground-contact shock and vibration vs flight vibration

An AGV pack lives on wheels or casters, taking continuous low-frequency vibration and periodic shock loading from floor seams, ramps, and door thresholds, day after day, for years. That's a different mechanical environment from a drone pack, which sees higher-frequency, propeller-driven vibration in the air but far less repeated shock loading against a hard structure. Mechanical mounting, cell retention, and connector strain relief all need to account for ground-contact duty specifically; a mounting design proven on a flight pack doesn't automatically carry over.

BMS Current-Tier Selection

Once the duty cycle's continuous and peak current are known, the BMS tier follows directly. Dan-Tech builds packs across four current tiers: 60-80A, 100A, 150A, and 200A.

Mapping duty-cycle class to a current tier (60-80A / 100A / 150A / 200A)

Size the tier to the peak, not the continuous figure. A pack that cruises at 55A continuous but spikes to 105A on every acceleration belongs on a 150A tier, not a 100A tier, even though its continuous number fits the smaller tier on paper. For a deeper look at what's inside the BMS itself, communication protocols, balancing, and protection architecture, see custom BMS design.

Matching the Connector to the Pack's Actual Current Draw

The connector is the last link in the sizing chain, and it needs to match the pack's real current, not its voltage class. Dan-Tech's connector lineup covers the range from light-duty to heavy industrial: XT60, XT90, AS150U, and Harting MPC30/MPC60.

The direction of the mistake is always the same: undersizing the connector for a peak current the pack can actually deliver. A 150A-tier pack running through an XT90-class connector will run that connector hot on every acceleration event, well before the cells or BMS show any stress, because XT90 tops out around 90A continuous. Size the connector to the same peak current used to pick the BMS tier, not to the cruise current, and step up a connector class whenever the peak sits near the top of the current one's rated range.

How This Differs from a 48V E-Bike / eMobility Pack

A 48V lithium pack for an e-bike and a 48V lithium pack for an AGV can use the same series/parallel math and land at the same nominal voltage, and still be two very different products underneath.

Duty cycle and operating environment

An e-bike pack sees intermittent use, hours of standby between rides, moderate continuous current, and a rider-controlled throttle that rarely commands a sustained peak for more than a few seconds. An AGV pack runs shifts, sometimes around the clock, with the acceleration/obstacle-recovery current spikes described above repeating dozens of times per hour, on a fixed indoor floor rather than variable outdoor terrain. The AGV pack needs a BMS and thermal design sized for sustained duty cycling, not just occasional peak demand.

Certification scope

eMobility and AGV/industrial packs are typically scoped against different sets of standards, because they sit in different regulatory categories: a consumer vehicle product versus an industrial machine component. A project can be scoped to meet whichever set of standards its actual end use requires, for example CE marking, UN 38.3 transport testing, RoHS, and IEC 62133 cell safety for an industrial pack, alongside whatever additional machinery-safety or vehicle-specific standards the integrator's own certification path calls for. Certification scope gets defined per project, based on the target market and application, not assumed from the voltage class alone.

Common Sizing Mistakes to Avoid

• Sizing the BMS to cruise current instead of peak current. The pack will work perfectly on a flat, empty floor and trip on the first obstacle-recovery cycle.
• Picking 14S for "more headroom" without checking the motor controller's absolute max voltage. A 58.8V full-charge pack can sit right at, or past, a controller's ceiling.
• Treating charge-side current as an afterthought. Opportunity-charging AGVs need the pack sized for the dock's actual charge current, not just the discharge side.
• Matching the connector to the BMS tier's label instead of the pack's real peak current. A 100A-rated BMS with a 150A peak draw upstream of it in the wiring still needs a connector sized for that 150A peak.
• Assuming "48V" means one exact voltage. 13S and 14S packs both carry the label; the real spec is the nominal, min, and max voltage window, not a single number.

Décisions clés : résumé

Sizing a 48V AGV or robotics pack is one connected decision chain, not four separate ones:

1. Classify the duty cycle: continuous drive current and peak acceleration/recovery current, plus charge-side current if the platform opportunity-charges.
2. Pick the cell and series count (13S or 14S, most commonly) against the motor controller's real input-voltage window, not just the "48V" label.
3. Size parallel groups for both target capacity and the cell-level current ceiling.
4. Select the BMS tier (60-80A / 100A / 150A / 200A) against the peak current, not the average.
5. Match the connector to that same peak current, not to the tier's nominal label.

FAQ

What does "48V" actually mean for a lithium battery pack?

It's a system class, not a literal voltage. A 48V-class lithium pack typically runs 44-52V nominal depending on the cell chemistry and series count; 13S and 14S configurations of a common cylindrical NMC cell both fall in that range and both get sold as "48V" packs.

Is 13S or 14S the right choice for a 48V AGV pack?

It depends on the motor controller's actual input-voltage ceiling and how many parallel groups the target capacity needs at each series count. 14S reaches a higher nominal and full-charge voltage from the same cell, which lowers current for a given power level but needs more headroom under the controller's max input.

What BMS current rating do I need for a 48V AGV battery?

Size it to the pack's peak current, not its cruise current. Acceleration and obstacle-recovery events routinely pull 1.5 to 2.5 times the sustained drive current, and Dan-Tech's four tiers (60-80A, 100A, 150A, 200A) should be picked against that peak figure.

Which connector should I use for a 48V AGV battery pack?

Match it to the same peak current used to select the BMS tier. XT60 and XT90 suit lighter-duty tiers; AS150U, Dan-Tech's standard Smart BMS connector, suits mid-to-high tiers; Harting's industrial MPC30/MPC60 connectors suit the highest tiers or any application needing a locking, vibration-rated connector.

How is a 48V AGV pack different from a 48V e-bike pack?

Same voltage class, different duty cycle. An AGV pack runs sustained, repeated current cycling across shifts on a fixed indoor floor; an e-bike pack sees intermittent, rider-controlled demand. Certification scope also differs by end-use category and gets defined per project.

Can a custom 48V pack use cells we already source ourselves?

Yes. Customer-supplied cells are a real option when the program already has a qualified cell with verifiable spec data; the pack, BMS, and mechanical/thermal design get built around that cell the same way they would around any cell in Dan-Tech's catalog.

What Dan-Tech Does: Dan-Tech Energy, custom Li-ion battery pack manufacturer with production in Germany and the US, builds the full chain covered in this guide into every custom pack: series/parallel configuration matched to the target motor controller, BMS current tier sized to the real duty cycle, and connector selection matched to actual peak current, not just a voltage label.

If you're sizing a 48V pack for an AGV or robotics platform, spec it with ToolBox and get a configuration built around your platform's real duty cycle rather than a generic 48V template. To see existing 48V-range configurations first, browse Dan-Tech's catalog.