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Fox ECS 2.88kWh HV Battery (Slave)-V2.0 Connector A
Fox ESS Fox ECS 2.88kWh HV Battery (Slave)-V2.0 Connector A
Fox ECS 2.88kWh HV Battery (Slave)-V2.0 Connector A
Fox ESS ECS 2900 high voltage series — 2.88 kWh a module, two to seven modules a stack, up to 20.16 kWh in one column.
Storage is worth having because it moves energy in time — solar generated at midday, or electricity bought on an overnight rate, spent in the evening. What decides whether it pays is the usable capacity, the charge rate and the cycle life, in that order.
Please read before ordering
If you are adding battery modules to a pre-existing Energy Cube stack, it’s important that the new batteries are compatible with your original battery modules. Please contact your Technical person via the portal and provide a photograph of the original battery stack to help us determine correct compatibility.
IMPORTANT REMINDER: When increasing the capacity of this battery stack, make sure the battery is the same connector type. We only stock the VERSION 2's of the ECS batteries. We stock both the Connector type A and Connector type B variations. This is the Connector type A variation.
About the Fox ESS ECS 2900 high voltage series
The ECS is the Energy Cube generation of Fox's high-voltage range: 2.88 kWh nominal a module, 2.59 kWh usable at a 90 % depth of discharge, and at least 6,000 cycles. Seven modules make 20.16 kWh.
It is a stack rather than a battery. One master module carries the battery management and the display; each slave adds capacity. Two modules is the minimum that will run, and the number your inverter accepts is in the table below.
IP65 for outdoor or indoor use, cooled by natural convection with no fans.
What each stack size gives you
Two modules is the smallest stack that will run and seven is the largest:
Which inverter will run this battery?
This is a Fox ESS high-voltage stack: modules wired in series to a few hundred volts, with one master carrying the battery management and the rest of the stack reporting to it.
How many of this module each Fox inverter family takes, from Product Compatibility Fox ESS UK 2026, the module count range for this inverter family:
Inverters we stock that will run it:
Stack rules, cabling and what else the job needs
The details that decide whether this battery suits the system:
- One master plus one to six slaves. Two modules minimum, seven maximum, 20.16 kWh at full stack.
- 25 A recommended discharge, 50 A maximum charge and discharge, 65 A peak for 30 seconds.
- Connector type matters. We stock the version 2 ECS modules in both connector A and connector B; every module in one stack must be the same type. Check the existing stack before ordering an addition.
- Fox's compatibility matrix counts the modules an inverter will carry in total. Where that number is larger than the maximum stack on the datasheet, it is because the inverter takes more than one stack in parallel — the per-stack limit still applies to each one.
- A stack is one module type throughout. Fox modules of different capacities are not mixed in a series string, and a Fox low-voltage battery will not work on a high-voltage inverter or the other way round.
- 570 mm wide and 380 mm deep at any stack size. 570 × 350 to 950 × 380 mm for two to seven modules, 67.1 kg at two modules to 229.1 kg at seven.
- Charge −10 °C to +55 °C, discharge −10 °C to +55 °C, storage −20 °C to +55 °C. Maximum altitude 2,000 m.
Where this battery earns its place
The ECS 2900 high voltage series is specified most often for these jobs.
Things worth knowing about this listing
- Register the installation with Fox ESS to activate the 12-year product warranty. Without registration it is 5 years. The registration page is at fox-ess.com, and the warranty document on this listing has the full terms.
Fox ESS ECS2900 technical data
Ordered with this battery more often than anything else
A battery is one part of a storage system. These are the parts our customers add most often:
Questions we get asked about this inverter
Is one module a battery?
No. A stack is one master plus at least one slave, so the smallest working system is two modules.
How many can I fit?
Seven in a stack, 20.16 kWh. How many your inverter will take is in the table on this page.
How much of it can I use?
2.59 kWh a module, at a 90 % depth of discharge.
Can I add these to an existing Fox stack?
Only to an ECS stack of the same module and the same connector type. Send us a photograph of the existing stack and we will confirm the part before you order.
Can it go outside?
Yes. IP65, outdoor or indoor, floor standing on the Fox stand.
Documents, advice and trade pricing
Every datasheet, certificate, installation manual and warranty document we hold for this product is in the Documents tab below. See the rest of our battery range, our hybrid inverters and our solar panels, or email sales@clearraysolar.com if you would like us to check a battery and inverter pairing before you order.
Build your complete solar system
Everything you need in one place.
- Inverters
- Batteries
- Mounting Systems
- Cabling & Accessories
- Protection Devices
Delivery times vary by region:
- UK — 1-2 business days
- Highlands & Islands — 1-2 business days
Returns accepted within 14 days of delivery for unused items in original packaging.
