Sigma 3.97kWh Stackable Batteries

Sigma 3.97kWh Stackable Batteries

$2,399.00 (Primary)

$2,099.00 (Secondary)

FINANCing availAbLE

Under the Inflation Reduction Act (2022), all energy storage systems over 5 kWh qualify for a 30% Federal Tax Credit.

Joule Case is the only scaleable battery system that powers limitless possibilities.

The Sigma Stackable Storage system is an advanced, scalable battery solution designed to meet a wide range of energy storage needs. With a base capacity of 3.97 kWh, it can be expanded up to 27.8 kWh, ensuring flexibility and adaptability for various applications. Featuring a 90% depth of discharge and high round-trip efficiency, Sigma delivers reliable performance with minimal energy loss. The system is easy to install with a plug-and-play setup, and its robust design allows for both indoor and outdoor use. With a voltage range up to 459.9 V and wide temperature tolerance, Sigma Stackable Storage is built to perform in diverse environments.



Battery Type

LiFePO4 Prismatic Cell



Cooling Method

Natural Convection

Depth of Discharge (%)




Humidity (%)

0 to 100 (No Condensing)

Ingress Protection


Installation Location

Outdoor / Indoor (Stand)

Max. Charge / Discharge Current (A)


Nominal Capacity (kWh/module)


Nominal Voltage (V/module)


Operating Temperature

14 to 131 (°F) / -10 to 55 (°C)

Operating Voltage (V)


Peak Discharge Current (A)

65A @60sec

Round-trip Efficiency



UL1973, UL9540, UL9540A


Max. 7 Modules in Series

Standard Warranty (Year)

Standard 12.5 years*1

Storage Temperature

-4° to 131 (°F) / -20 to 55 (°C)






84.9 lbs. (P) | 76.8 lbs. (S)


22.4 x 9.1 x 15.0in (P) | 22.4 x 4.7 x 15.0in (S)

Warranty & Returns


Returns notice - For any returns where there are technical issues or breakage, you can return and money will be refunded. If the shipping box has been opened and the product is in working shape, you cannot be refunded due to the nature of this product. If our customer service team determines that this is a warranty matter, we will have you ship it back to us. You must properly package the product including proof of your purchase date with the product. You must then send the product by mail or courier, with shipping costs paid by you, to Joule Case at 121 E 38th St, Suite 102, Garden City, ID, USA 83714. We will process your return and send your repaired or replacement product to you, at our expense, for warrantied products being shipped to locations in North America.

For products purchased or being shipped outside of North America, please contact the local distributor from whom you purchased the product, or email to obtain further distributor information.

Shipping Information


Shipping costs are additional and are based on the size of the order and the destination.

Product Features


Expandable battery system designed to charge using renewable or on-grid sources.

No Fumes

Traditional generators produce toxic, harmful fumes that are bad for humans and the environment.

No Noise

Our batteries are silent—no shouting to have a conversation or being drowned out by the constant hum of a generator.


The stackable design gives you the control to add more power based on your needs.

The power to do anything

50" TV (110W)

Up to 250 hrs*

Espresso Machine (2200W)

Up to 12.5 hrs*

Freezer (400W)

Up to 69.5 hrs*

Microwave (1000W)

Up to 27.8 hrs*

*based on average wattage

See why our battery systems are the solution for you


Customer Success Stories

Not sure if Joule Case can handle your power needs? Let us prove you wrong.