CESC battery storage
Mercury 261
261 kWh
Storage system 261 kWh, 125 kW, lithium iron phosphate cell 314 Ah, 832 V nominal, 1.44 square metre footprint.
Datasheet provided with the quote.
Sold delivered, commissioned by the factory engineers. Installation and connection are the responsibility of the site’s installer.
The product
What the Mercury 261 looks like
Storage system 261 kWh, 125 kW, lithium iron phosphate cell 314 Ah, 832 V nominal, 1.44 square metre footprint.
Manufacturer CESC, September 2026 data sheets
261kWh
Capacity of the Mercury 261, per cabinet.
CESC manufacturer
Specifications
| Specification | Value | Source |
|---|---|---|
| Electrical | ||
| Capacity | 261 kWh | CESC manufacturer |
| Power | 125 kW, external hybrid inverter | CESC manufacturer |
| Cell | LFP 314 Ah | CESC manufacturer |
| Nominal DC voltage | 832 V | CESC manufacturer |
| Grid connection | 400 V three-phase, 3P+N+PE | European distributor |
| Solar oversizing | native 2:1 ratio, integrated transfer switch | CESC manufacturer |
| Mechanical | ||
| Footprint | 1,44 m² | CESC manufacturer |
| Ingress protection | IP55 | European distributor |
| Environment | ||
| Anti-corrosion | up to C5, coastal sites | CESC manufacturer |
| Standards cited | ||
| Standards | UN 38.3, IEC 62619, IEC 63056, IEC 61000, IEC 62477 | Manufacturer documentation |
- Capacity
- 261 kWh
- CESC manufacturer
- Power
- 125 kW, external hybrid inverter
- CESC manufacturer
- Cell
- LFP 314 Ah
- CESC manufacturer
- Nominal DC voltage
- 832 V
- CESC manufacturer
- Grid connection
- 400 V three-phase, 3P+N+PE
- European distributor
- Solar oversizing
- native 2:1 ratio, integrated transfer switch
- CESC manufacturer
- Footprint
- 1,44 m²
- CESC manufacturer
- Ingress protection
- IP55
- European distributor
- Anti-corrosion
- up to C5, coastal sites
- CESC manufacturer
- Standards
- UN 38.3, IEC 62619, IEC 63056, IEC 61000, IEC 62477
- Manufacturer documentation
Electrical
Mechanical
Environment
Standards cited
Specifications recorded on 15/09/2026. Source given line by line. The precise source is provided with the quote.
Specifications taken from CESC manufacturer documentation and from its European distributors. Citing a standard is not the same as producing a certificate: certificates are provided on request with the quote. Specifications that are not published are given in the quote.
This document is a record compiled by Stellabox Energy on the date shown, from the sources cited against each value. It is not a manufacturer’s datasheet and does not replace one. The contractual specifications are those of the quote.
What the manufacturer highlights
The Mercury 261, as CESC presents it
- 314 Ah
- Lithium iron phosphate cells
- 24 hours a day
- Operating conditions, seven days a week
- 3 levels
- Of fire protection
- 100%
- Of cells monitored for temperature
- 1.5 hours
- Of fire resistance at cabinet level
- Three-phase
- Unbalanced three-phase output permitted
- 1 year
- Of local data retention
- C4
- Anti-corrosion class, beyond 5 km from the coastline
Manufacturer CESC, September 2026 data sheets
The enclosure and the climate
Anti-corrosion class C4
The C4 treatment is intended for sites located more than 5 km from the coastline. The manufacturer states a nominal service life of 15 years, protected from corrosion.
For a coastal site, the data sheet of this model cites a treatment up to C5.
- > 5 km
- from the coastline
- 15 years
- of nominal service life, protected from corrosion
Manufacturer CESC, September 2026 data sheets
What this model can do
Shave power peaks
An industrial site is billed on the highest peak measured during the month. Starting machines or a chiller is enough to push it up. The battery covers the excess instead of the grid.
Consume your own generation
Electricity generated in the middle of the day by a photovoltaic system is used in the evening, instead of being exported to the grid.
Arbitrage the price of electricity
Charge when electricity is cheap, discharge when it is expensive. The on-board control system decides, based on prices and on your load curve, with no intervention.
Run without the grid
The Mercury units operate grid-connected or off-grid. Changeover and back-up power are defined at configuration.
Charge fast without upgrading the connection
A fast charger draws power that a site’s grid connection cannot always supply. The battery acts as a buffer between the grid and the charger.
Support a solar farm
On a new or an existing plant, storage smooths generation, shifts export and holds the power committed to the grid operator.
Scalability
Extensible jusqu’à 5,22 MWh en assemblant 20 unités. Donnée constructeur CESC.
Pair it with a fast charger
A DC charger draws power that a site’s grid connection cannot always supply. The battery acts as a buffer.
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