MEB 590 Battery Pack Design: 400 V and 800 V Worked Examples

19 October 2026

Short answer: MEB 590 battery pack design starts with the voltage window your inverter or motor controller accepts, not the nominal voltage alone. For a 400 V system, 14 modules of the 2P8S type in series gives 411 V nominal (window 313.6-487.2 V, 93.2 kWh); for 800 V, 27 modules gives 792.7 V nominal (window 604.8-939.6 V, 179.8 kWh).

When an integrator sizes a pack around MEB 590 modules, the first decision is how many modules to place in series. That number is not derived from a nominal voltage target; it is derived from the voltage window that the downstream power electronics will tolerate across the full state-of-charge range. Get that window wrong and the system will either cut off early on discharge or refuse to charge to full capacity. This article works through two module types and four string configurations so you can check the arithmetic against your own inverter specification before committing to a layout.

The reference modules

All calculations on this page use catalogue data from two MEB 590 module variants. For detailed dimensional and electrical specifications, see the MEB 590 module specifications page.

2P8S module, the reference configuration: - Nominal voltage: 29.36 V - Voltage window: 22.4 V (minimum) to 34.8 V (maximum) - Capacity: 227 Ah - Energy: 6.66 kWh - Rated current: 227 A (1C) - Mass: 31.4 kg - Dimensions: 590 x 225 x 110 mm - Cycle life: approximately 1,200 cycles at 80 % DoD

1P12S module, higher module voltage, fewer modules in series: - Nominal voltage: 44.4 V - Voltage window: 33.6 V (minimum) to 52.2 V (maximum) - Capacity: 147 Ah - Energy: 6.53 kWh - Mass: 30.25 kg - Dimensions: 599 x 225 x 108 mm - Cycle life: approximately 2,000 cycles at 80 % DoD

The catalogue lists the 1P12S length as 599 mm in one field and 594 mm in another; in both cases it is not 590 mm. Confirm the datasheet value if your pack envelope is sized to exactly 590 mm module length.

Voltage window first, module count second

Every lithium cell chemistry has a minimum and maximum cell voltage. Multiply those by the number of cells in series and you get the string window. Your BMS must keep the string within that window; your inverter must accept the full range. If the inverter's maximum input voltage is lower than the string's top-of-charge voltage, cells will be left partly uncharged. If the inverter's minimum operating voltage is higher than the string's discharged voltage, usable energy is lost.

Worked examples: 2P8S module

14 modules in series (400 V class)

Nominal string voltage: 14 x 29.36 V = 411.0 V
Minimum voltage (fully discharged): 14 x 22.4 V = 313.6 V
Maximum voltage (fully charged): 14 x 34.8 V = 487.2 V
Total energy: 14 x 6.66 kWh = 93.2 kWh
Module mass: 14 x 31.4 kg = 439.6 kg
Rated string current: 227 A (1C, set by the module rating)
Rated string power at 1C: approximately 93 kW (calculated at nominal voltage)

An inverter sized for a 400 V nominal bus must therefore accept inputs from 313.6 V up to 487.2 V to use the full capacity of this string.

27 modules in series (800 V class)

Nominal string voltage: 27 x 29.36 V = 792.7 V
Minimum voltage: 27 x 22.4 V = 604.8 V
Maximum voltage: 27 x 34.8 V = 939.6 V
Total energy: 27 x 6.66 kWh = 179.8 kWh
Module mass: 27 x 31.4 kg = 847.8 kg
Rated string current: 227 A (1C)
Rated string power at 1C: approximately 180 kW (calculated at nominal voltage)

At 939.6 V maximum, some inverters rated for 800 V nominal will be near or above their absolute maximum input voltage. Confirm the inverter's overvoltage limit before finalising the module count.

Worked examples: 1P12S module

9 modules in series (400 V class)

Nominal string voltage: 9 x 44.4 V = 399.6 V
Minimum voltage: 9 x 33.6 V = 302.4 V
Maximum voltage: 9 x 52.2 V = 469.8 V
Total energy: 9 x 6.53 kWh = 58.7 kWh
Module mass: 9 x 30.25 kg = 272.3 kg

18 modules in series (800 V class)

Nominal string voltage: 18 x 44.4 V = 799.2 V
Minimum voltage: 18 x 33.6 V = 604.8 V
Maximum voltage: 18 x 52.2 V = 939.6 V
Total energy: 18 x 6.53 kWh = 117.5 kWh
Module mass: 18 x 30.25 kg = 544.5 kg

Summary table

Configuration	Modules in series	Nominal voltage	Voltage window	Energy	Module mass
2P8S, 400 V class	14	411.0 V	313.6-487.2 V	93.2 kWh	439.6 kg
2P8S, 800 V class	27	792.7 V	604.8-939.6 V	179.8 kWh	847.8 kg
1P12S, 400 V class	9	399.6 V	302.4-469.8 V	58.7 kWh	272.3 kg
1P12S, 800 V class	18	799.2 V	604.8-939.6 V	117.5 kWh	544.5 kg

All module mass figures cover the modules only. Enclosure, cooling plates, busbars, cabling and thermal management hardware add to the total pack mass; no figure for those items is given here because they vary with pack architecture.

Parallel strings: energy, current and coupling

Placing two or more strings in parallel multiplies energy and rated current proportionally. Two parallel strings of 14 x 2P8S gives 186.4 kWh and 454 A rated current at 411 V nominal. The practical implications grow with string count: passive parallel coupling requires closely matched state of charge at connection; active coupling through contactors or DC-DC converters adds complexity and cost. The BMS scope must reflect the topology chosen; what is included per module varies by product and must be confirmed per project.

For a fuller picture of where MEB 590 modules are used, including multi-string stationary installations, that page covers both vehicle and storage contexts.

A note on cycle life and application fit

The 2P8S module is rated for approximately 1,200 cycles at 80 % DoD; the 1P12S for approximately 2,000 cycles at 80 % DoD. At one full cycle per day, 1,200 cycles is about 3.3 years and 2,000 cycles about 5.5 years (cycles divided by 365). That fits vehicle duty. A stationary system cycled daily reaches the same cycle count in the same time.

Applications requiring 8,000 or more cycles at 80 % DoD, such as daily-cycle grid storage, industrial UPS and commercial peak shaving, are better served by purpose-built ESS modules. The MEB 590 module energy storage page discusses where the automotive format is appropriate and where it is not.

For ESS-rated alternatives with 8,000-cycle specifications, Avantis Energy's module range covers both vehicle-format and purpose-built stationary modules.

Frequently asked questions

How many MEB 590 modules in series for a 400 V battery pack?
Using the 2P8S module (29.36 V nominal), 14 modules in series gives 411 V nominal with a voltage window of 313.6-487.2 V and 93.2 kWh. Using the 1P12S module (44.4 V nominal), 9 modules in series gives 399.6 V nominal with a window of 302.4-469.8 V and 58.7 kWh.

Why does the voltage window matter more than nominal voltage in pack design?
The inverter or motor controller must operate across the full range from minimum discharged voltage to maximum charged voltage. If the inverter's input limits fall inside that window, usable capacity is lost. The string count must be chosen so the complete voltage window falls within the power electronics specification.

What is the module mass of a 27-module MEB 590 string for an 800 V system?
Using the 2P8S module at 31.4 kg each, 27 modules have a combined mass of approximately 848 kg. This covers modules only; enclosure, cooling hardware, busbars and cabling are additional and depend on the pack design.

Can MEB 590 modules be used in stationary energy storage?
They can, but cycle life is the limiting factor. The 2P8S is rated for approximately 1,200 cycles and the 1P12S for approximately 2,000 cycles, both at 80 % DoD. For applications requiring 8,000 or more cycles, purpose-built ESS modules are the more appropriate choice.

Does the 1P12S module fit the same envelope as the 2P8S?
Not exactly. The 1P12S measures 599 x 225 x 108 mm against 590 x 225 x 110 mm for the 2P8S. The catalogue lists the 1P12S length as 599 mm in one field and 594 mm in another, against 590 mm for the 2P8S, and a height of 108 mm against 110 mm. Verify these against the pack enclosure before the two types are treated as interchangeable.

Discuss your pack design

Discuss your pack requirements with Avantis Energy to confirm module selection and string configuration for your voltage class and cycle requirements.