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DC-coupled salt battery storage

for commercial, industrial and neighbourhood applications

from 100 kWh to 1.4 MWh

You are planning to install photovoltaics on several roof surfaces or on a larger structure. You expect to produce a lot of surplus energy. But you don't want to feed the electricity into the grid uneconomically. Perhaps the grid connection capacity is not sufficient and a grid expansion would be necessary. That is why you are thinking of a storage solution. What if you could convert your project to DC much more efficiently and save yourself the grid expansion? You would kill two birds with one stone.

innovenergy offers you economically viable salt-based DC storage batteries:

  • DC-coupled storage battery including 10 kW bidirectional DC/DC converter (on board).
  • Maintenance-free salt batteries with 9 kWh (250 V) or 22 kWh (620 V) storage capacity
  • Storage capacity scalable up to 1.4 MWh
  • 9 kWh salt battery freely combineable with 22 kWh salt battery
  • Intelligent control for optimising own demand and peak shaving

The DC-coupled salt battery storage is a system component of the DCmaxx©, a DC microgrid and can only be operated on such a DC grid (DC link).

You already have an existing photovoltaic system with PV inverter? Then we recommend one of the AC-coupled saline battery storage systems salidomo© or salitrust©.

The salimax© is a DC-coupled salt battery storage system for large photovoltaic systems and corresponding storage needs. The DC salt batteries can also be installed in an emergency power-capable, island-capable system. The DC-coupled salt battery storage works with PV inverters from KACO, REFU and for larger systems with Indrivetec (up to 3 MW). The salimax© is available in two battery sizes, which can be scaled as desired and also mixed. With the salimax©, storage systems from around 100 kWh up to 1.4 MWh can be realised.


New photovoltaic system with AMPT DC/DC convertersfrom 100 kWp

Variants Battery Storage

 salimax© 9salimax© 22
Storage capacity9 kWh22 kWh
DC/DC converter power10 kW10 kW
Maximum storage capacity500 kWh1.4 MWh
Number of batteries per rack64
DC safety elementsyesyes


 salimax© 9salimax© 22
Type of systemDC-coupled salt-based storage battery
KFW subsidyyes, 10-year fair market value guarantee
Requirements Installation sitedry, indoor
Fire and personnel protection requirementsusual personnel protection, no fire protection measures necessary
Extension of battery capacityat any time, old + new batteries can be combined
Installation effortdepending on local conditions and total storage size
Dimensions storage battery (WxHxD)558 x 320 x 496 mm540 x 390 x 970 mm
Battery weight105 kg255 kg

Battery storage

 salimax© 9salimax© 22
Battery typeSalt battery (molten salt or ZEBRA cell)
Chemical descriptionNaNiCl2 (sodium nickel chloride)
Battery manufacturer / ProductFZSoNick + innovenergy / salimax©
Expected life at 80 % DoD (years/deep cycles/shallow cycles)15 years / > 4500 / > 8500
Nominal storage size at 100 % DoD9.2 kWh22.5 kWh
Daily usable storage at 85 % DoD7.8 kWh19 kWh
Maximum C rate (charge/discharge rate)0.25 C / 0.5 C
Nominal battery voltage250 V620 V
Battery efficiency during standard cycle90 %

Bidirectional inverter smaller systems

Grid feed-in and grid drawDCmaxx© 
DC/AC inverterbi-directional
ManufacturerTrumpf Hüttinger (DE)
Rated output power/voltage/frequency25 kVA pro module / 3-phase, 400 VAC / 50 Hz
up to16 modules = 400 kVA
Maximum charge/discharge efficiency97 %
Galvanic isolation (battery from system)yes

Bidirectional inverter large systems

Grid feed-in and grid drawDCmaxx© 
DC/AC inverterbi-directional
ManufacturerIndrivetec AG (CH)
Rated output power/voltage/frequency320 kVA, 500 kVA, 750 kVA, 1 MVA / 3-phase, 400 VAC / 50 Hz
Maximum charge/discharge efficiency97 %
Galvanic isolation (battery from system)yes

Unidirectional inverter

Mains feed onlyDCmaxx© 
DC/AC inverterunidirectional
ManufacturerKACO New Energy, REFU
Rated output power/voltage/frequency50-105 kVA per module / 3-phase, 400 VAC / 50 Hz
Maximum charge/discharge efficiency97 %
Galvanic isolation (battery from system)yes

Energy management

Switchover to off-grid operationautomatic switchover with interruption possible
Self-consumption optimisationintegrated and configurable
Visualisation, data analysis, energy statisticsLocal PC access, web platform, mobile app


Up to 64 salimax© (à 22 kWh) can be connected in tandem. An extension is possible at any time, even years later.


There are no early recycling or disposal fees. However, the transport of the battery to be discarded back to the manufacturer in Stabio/CH must be borne by the customer. There, the complete battery is returned to its raw material cycle.


Without further conditions, the salt battery is covered directly by the manufacturer with a time-value guarantee of 10 years. The battery inverters are covered by a 5-year warranty. Everything else is covered by a standard 2-year warranty. The warranty is an device warranty. Travel costs and working hours will be charged separately in the event of replacement or faults, unless you have subscribed to a service contract for the relevant year.

innovenergy Warranty Conditions


EN 55022 Continuous disturbance voltage | EN 55014 -1 Discontinuous disturbance voltage | EN 55011 Radiated disturbance | EN 61000-4-2 Electrostatic discharge | EN 61000-4-3 Radiated electromagnetic field | EN 61000-4-4 Electrical Fast Transients | EN 61000-4-5 Surge | EN 61000-4-6 Injected currents | GR1089 | FCC Class A | IEC 60529 IP Protection Degree

Advantages of the salt battery

The salt batteries of the innovenergy storage solution are made of harmless materials: 32 % common salt, 22 % nickel, 22 % iron, 20 % ceramic.

The recycling of the salt battery has been standardised for 15 years. The metals are melted down and returned to the metal industry. The battery is manufactured 100% in Switzerland according to Swiss environmental and labour standards.

The salt battery is absolutely safe - the rooms do not need any fire protection or fire warning devices as the battery is neither flammable nor can it explode. It can also be operated in very cold and very warm rooms (-20° to +60° C) without ventilation or air conditioning. The outside temperature does not affect the storage capacity or the service life.

The battery survives a total discharge without damage. The salt battery has a service life of at least 15 years (10-year guarantee) and is maintenance-free.

The salt battery is extremely robust and is used by the thousands in the telecommunications industry. In industry, it is considered a cheap and safe electricity storage technology in the long term. With innovenergy, this technology is now also available for domestic use and for businesses.

You can find more information under Salt Technology.

You want to know what the whole system costs now? ​​​​​​
The salimax© is a system component of the DCmaxx© and only available within such a DC-coupled system. For a concrete project enquiry within a DCmaxx© overall system, click on the "Start enquiry" button on the left.