Fortress Battery

Build a Battery Bank You Can Depend on With Fortress 

You can’t go wrong storing surplus energy in Fortress batteries. Every model we carry at The Solar Store is crafted from lithium iron phosphate cells rated for 8,000 cycles and backed by a 10-year warranty, so you can rest assured you’re getting a durable, long-lasting solution.

Contractors and off-grid homeowners consistently specify Fortress when they want something to perform decade after decade. You can shop the full range here at The Solar Store, including:

• eFlex MAX: 5.4 kWh per module at 51.2V. Capable of stacking up to 16 units in parallel for 86.4 kWh of total capacity. It’s IP65-rated with an integrated 125A breaker built into the BMS.
• eBoost 16: 16 kWh per module, topping out at 256 kWh across 16 units.
• eSpire Nano: Made for serious commercial loads at 40 and 60 kWh per unit. Available in indoor and outdoor configurations.

Every unit is managed via digital BMS to monitor and balance each individual cell. The system stays current without you having to make a service call thanks to OTA firmware updates. The DuraRack fits up to four eFlex modules in one solar battery box for outdoor installations. The DuraRack Mini can fit two if you have a smaller system.

You already know the limitations if you’re moving away from a sealed AGM battery or flooded lead-acid battery. A Fortress battery provides 100% depth of discharge and 8,000 cycles, dramatically outperforming the alternatives. There’s no maintenance since LFP doesn’t need watering or equalizing charges, either. Make the upgrade today. 

Why Buy a Fortress Battery at The Solar Store?

This has been your one-stop shop for solar energy systems for more than 25 years now. We carry the latest and greatest technology from the best brands the industry has to offer - not just Fortress, but many others as well. Our mission is to help you build the perfect system within your budget. Get in touch today for personalized support from A to Z!

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Frequently asked questions

Are Fortress batteries good?

Yes, these are among the best lithium iron phosphate batteries you can buy. They’re built with automotive-grade prismatic cells with an 8,000-cycle rating and a 10-year warranty.  

What is the price of a Fortress battery?

We have Fortress batteries starting at $3,780. They’re not cheap, but you get what you pay for. These batteries are built to last. You can reach out to our customer service team for a personalized quote. 

Where are Fortress batteries made?

Fortress is headquartered in Pennsylvania. 

How many Fortress batteries do I need?

You need to know your daily energy usage in kWh. Each eFlex MAX stores 5.4 kWh; the eBoost gives you 16 kWh. Just divide your daily consumption by the module capacity and add a little buffer to be safe. Our team is ready to size the right Fortress battery setup for your needs, so just reach out!