Fortress Power FlexTower with Envy True 12 kWh Inverter and 3 eFlex 5.4 kWh LFP Batteries
In Stock & Ready to Ship
All orders are shipped within 1-2 business days. Product ETA 7-14 business days.
Elevate your energy independence with the ultimate power bundle. Our FlexTower, equipped with the DuraRack battery cabinet, combines an all-in-one energy storage system with an Envy True 12 kW inverter and three to four eFlex 5.4 kWh batteries. Whether your goal is to maintain home power during an outage or decrease your grid dependency, the FlexTower with Envy True 12 kW Inverter and eFlex batteries bundle offers the ideal solution.
FlexTower
The FlexTower is an all-in-one energy storage system. Built on the foundation of the DuraRack battery cabinet, the FlexTower combines the battery, charge controller, and inverter into a single unit with an LCD control panel, and remote monitoring capability. The FlexTower is easy to install and carries IP65/NEMA3R ratings for indoor or outdoor use.
Key Features:
All-in-One Solution
- Inverter, charge controller, LCD Control Panel, Battery and remote monitoring app integrated in one unit
- Supports Off-grid, Back-up, Zero Export, Time-of-Use, Demand Response, Peak Shaving, and Virtual Power Plant
Flexible & Easy Install
- IP65 water and dust proof for indoor & outdoor installation. NEMA3R
- AC or DC couple to existing or new PV arrays
- Optional Rapid Shutdown Button Included
- Side knockouts sized for solar, grid, and generator wiring
Highest Reliability for Maximal Protection
- 8000+ cycle life with tier 1 Automotive Lithium Iron Phosphate (LFP) battery
- Easily scaled to meet all large residential and commercial electricity needs
Whole Home Backup with 200A Grid Pass-Through
- 200A Pass-through eliminates backup panel requirement
- Saves time on inverter wiring
- Includes battery cables and combiner for additional savings
Highest Roundtrip Efficiency to Maximize Your Solar Investment
- >98% Battery Efficiency
- 5% CEC-Rated Inverter Efficiency
- Compatible with Din-Rail Heaters to maximize lifecycles in cold climates
Envy True 12 kWh Inverter
The Fortress Power Envy True 12 kW – a whole-home, all-in-one 12kW inverter solution. Paired with the Fortress Power eFlex 5.4 kWh, the eVault Max 18.5 kWh, or LEP-10 MAX batteries, the Envy features a 200A AC passthrough providing up to 12kW (50A @ 240V) of whole-home backup power. The Envy features a built-in generator input with AC/DC coupling, on- and off-grid capabilities, plus a 3 MPPT output allowing for a maximum of 21 kW PV array. The Envy is equipped with a built-in APsmart Module Level Rapid Shutdown Transmitter and Button, along with Pre-built AC & DC breakers allowing for fast installation and commissioning. Use our online monitoring app to access your system from anywhere.
Key Features:
- 200A AC Passthrough Current For Whole Home Backup
- 3 MPPT Output For Max. 21 KW PV Array
- AC, DC And AC/DC Combined Coupling
- IP65 Rated For Indoor & Outdoor Installation
- Built-In Generator Input
- 10 Units In Parallel
- Local And Remote Monitoring/App
- Color LCD Touch Screen
- Batch Settings
Supported Applications:
- Backup
- Off-Grid
- Zero Export
- Time-Of-Use
- Peak Shaving
- Demand Response Integration (Coming Soon)
Whole-Home Backup/AC Passthrough One-Line Diagram
eFlex 5.4 kWH LFP Battery
The Fortress Power eFlex is a 5.4 kWh scalable energy storage solution based on safe and energy dense prismatic Lithium Iron Phosphate cells. The digital processor Battery Management System (BMS) includes high amperage contactor disconnects and advanced Closed-Loop inverter communication, as well as individual cell voltage monitoring, temperature monitoring, and cell balancing to maximize reliability and longevity.
Canbus, modbus, and wifi communication enable internet-of-things compatibility. The IP65 case ensures direct water spray and dust will not penetrate the battery internals from all directions. The unit can be wall mounted, floor mounted, and server rack mounted for hard-to-reach access in renewable, marine, RV, mobile, telecom, railway applications and more.
Key Features:
- Rugged, Long-lasting, Daily Use Battery
- Safe Lithium Iron Phosphate Technology (LifeP04)
- 98% Round Trip Efficiency
- Flexible Mounting Options
- Remote Monitoring including wifi, modbus, and canbus
- BMS Monitors & Balances Individual Cells
- NRTL certified to UL9540 and UL9540a standards
Specifications
| DuraRack Specifications | |
| Enclosure Material | Carbon Steel |
| Enclosure Protection | IP65 water and dust proven (outdoor) |
| Enclosure Color | White |
| Dimensions [W x H x D] | 29.29 x 41.34 x 18.03 in (744 x 1050 x 458 mm) |
| Enclosure Weight | 59.6 kg / 153.2 lbs |
| Maximum Battery Units | 4 eFlex 5.4 |
| Storage Capacity Range | 5.4kWh – 21.6 kWh per unit |
| Max. Storage Capacity | 81 kWh (4 unites in parallel) |
| Knockout Size | 1inch & 2 inch |
| Positive and Negative Battery Busbars | 2 x 4 points; M8 (5/16) Terminal Rings |
| Positive and Negative Busbars to Inveter | 2 points; m10 (3/8) Terminal Rings |
| Battery Cables | 4 sets of |
| Terminal Torque | 7.0 – 7.7 Nm (5.1 – 5.7 ft-lb) |
| Enclosure Warranty | 3 Years |
| Certifications | UL9540, UL9540A, UL1973, CEC, SGIP |
| Envy True 12 kWh Inverter Input DC (PV Side) |
|
| Max. DC Input Power for Single MPPT | 12000W/7000W/7000W 1 x 12kW, 2 x 7kW |
| Max. PV Input Power | 21000W |
| Max. PV Power Delivered to Battery & AC Outputs | 18000W |
| DC Input Voltage Range | 100V-600V |
| Nominal DC Input Voltage | 360V |
| Full Power MPPT Voltage Range | 230V-500V |
| Max. DC Input Current | 25A/15A/15A |
| MPPT Number/(Strings per MPPT) | 3(2/1/1) |
| Output/Input AC (Grid) | |
| Continuous AC Power to Grid | 12000W (240V) |
| Continuous AC Power to Load with Grid or Generator | 48000W (240V) |
| Nominal Output Voltage | 120V/240V |
| Max. Continuous AC Current | 50A @ 240V |
| Nominal AC Frequency | 50Hz/60Hz |
| Output AC (Off-Grid) | |
| Max. Output Power | 12000W (240V) |
| Nominal Output Voltage | 120V/240V |
| Nominal Output Frequency | 50Hz/60hZ |
| Nominal Output Current | 50A @ 240V |
| Peak Power | 14kW 10 minutes / 16kW 5 minutes / 20kW 500ms |
| Switching Time | Seamless |
| Battery Parameters | |
| Compatible Battery Type | Lithium and Lead acid batteries |
| Nominal Battery Voltage | 48V |
| Battery Voltage Range | 48V-56V |
| Maximum Charging/Discharging Current | 250A |
| Maximum Charging/Discharging Power | 12000W |
| Efficiency | |
| MPPT Efficiency | 99.9% |
| Max. Efficiency | 97.5% |
| CEC Efficiency | 96.5% |
| Protection | |
| Anti-islanding Protection | YES |
| DC Switch | YES |
| Ingress Protect Degree | NEMA 4X, IP65 |
| SPD Protection | YES |
| AFCI | OPT |
| RSD | Built-in APsmart Transmitter |
| General Data | |
| Dimensions | 31.1 x 20.5 x 10.4 in (790 x 520 x 264 mm) |
| Weight | 127 lbs (58 kg) |
| Display | Color LCD |
| Ambient Temperature Range | -20 to 60 °C (-4 to 140 °F) |
| Cooling | FAN |
| Communication | RS485/Wi-Fi/CAN |
| Standard & Certification | |
| Certifications | UL1741, UL1741SB, IEEE1547A, Rule 21, ISO-NE, FCC15 class B, HECO, CEC, Luma, SGIP, NOM |
| Warranty | 10 Years / Lead Acid or Fortress Lithium Batteries , other 48v battery manufacturers** ** BATTERIES TO BE CONFIGURED IN OPEN LOOP COMMUNICATION |
| eFlex 5.4kWh LFP Battery | |
| Name | eFlex 5.4 |
| Total Energy(kWh) | 5.4 |
| Max. Charge Current (Continuous) [A] | 100 |
| Max. Discharge Current (Continuous) [A] | 60 |
| Max. Pulse Current (for 5 sec) [A] | 130 |
| Capacity [Ah] | 105 |
| Voltage Range [V] | 48-55 |
| Charging Temperature [F] | 32 to 113 |
| Discharging Temperature [F] | 32 to 140 |
| Storage Temperature [F] | 32 to 95 |
| Dimension [L x W x H, inch] | 21.5 x 17.5 x 7.2 |
| Weight [lbs] | 116 |
| Life Cycles | 8000 @ 80% DoD |
| Round Trip Efficiency | >98% |
Document Library
Fortress - Online Inverter Integration Guides
Envy Inverter 12 kW Specifications
Envy Inverter 12 kW Install Manual
Envy Battery-inverter Integrations guide
Envy inverter Monitoring setup guide
Fortress eFLEX 5.4kWh Data Sheet
Fortress Power eFLEX Installation Manual
Fortress eFlex UL9540 Certificate
Shipping Information
FREE & FAST SHIPPING SAVE Hundreds Today with Free Shipping on All Orders. We Ship to ALL 48 Lower States (We do not ship to Puerto Rico, Hawaii, Alaska)
Lead Time - 3-7 Business Days Depending on Product - Once You Place an Order, We immediately begin processing, the order request is sent to our warehouse and is prepared for pickup, it then usually takes around 3-7 business days to be picked up for transit.
Transit Time - Transit Time can vary depending on the distance between your location and the warehouse but you can expect the item to arrive between 3-8 business days after pickup.
Our Shipping Partners: FedEx, UPS, Freight Club (among others)
We partner with the most reliable freight companies in the USA to ensure your order arrives safe and in a timely manner.
Your Item will ship from warehouses all across the United States to ensure fast and efficient delivery times for our customers.
If there are any delays regarding your product shipment, we will let you know in advance. .png)
.png)
Order Confirmation:
As soon as you place your order, you will receive an order confirmation e-mail. (please allow a few hours for this to come through in some cases) This means that we have received your order in our system and pre-authorized your credit card for the purchase.
As soon as we receive your order, we automatically reach out to our suppliers to confirm that it is in stock and available for immediate shipment.
If your item is on backorder or unavailable, we will void the pre-authorization and reach out to you via e-mail. If your item(s) are available for immediate shipment (within 5 business days), we will process the charges and submit the order for shipment.
Order Shipment:
If your order is in stock and we process the charges to your credit card, it will ship within five business days from the date of your order. We will send you tracking information within 24 hours of your order leaving the warehouse to the e-mail address you provided when checking out. If you do not receive tracking information from us within six business days of your order, feel free to follow up with us at sales@buildthepower.com
No Shipping outside the USA. (Some exceptions apply - if the website permits you to check out and enter your shipping address, you will receive your order. Some products in particular are available in Canada).
Shipping Options
Our base "Curb-side" Pickup shipping is always completely free! This option usually takes between 5-15 days to arrive at your doorstep, after you have submitted your order.
Threshold Shipping: This involves the item being brought onto your porch, or into a sheltered/garage area.
Double-Check Your Address
To ensure that your package is properly delivered and that you receive your package within the time frames we advertise, please
make sure that your address is correctly entered and includes all relevant and/or required information. The use of correct
abbreviations, street numbers, building or apartment numbers, and route information (if applicable) is critical for ensuring
timely delivery. We do not take responsibility for lost, misplaced, or incorrectly delivered shipments if the address information
provided is incorrect or incorrectly entered at the time of purchase.
Damages
Please inspect the packaging of your item(s) when they arrive, if you notice any damage, you should make note of it when signing for delivery. If your item(s) do arrived damaged please send photos of damage, box and SKU, along with a brief description of the damage to sales@buildthepower.com and we will process an insurance claim on your behalf. Photos and videos must be sent for freight damage within 24 hours of arrival or the freight damage claim will not be valid. Any punctures, or visible signs of exterior damage must be reported within 24 hours.
Warranty
10 Years
Return Information
We have a 30-day return policy, which means you have 30 days after receiving your item to request a return.
Should you decide to cancel your order prior to its shipment, a 3% deduction will be applied to cover platform fee expenses from the total paid amount.
To be eligible for a return, your item must be in the same condition that you received it, unworn or unused, with tags, and in its original packaging. You’ll also need the receipt or proof of purchase. Items that are not in this condition will not be accepted.
To start a return, you can contact us at sales@buildthepower.com If your return is accepted, we'll send you a return shipping label, as well as instructions on how and where to send your package. Items sent back to us without first requesting a return will not be accepted.
Returns for reasons other than damaged items will require a 15-25% re-stocking fee, this depends on the size and freight cost of the item to ship back, we sell large items and shipping can be costly.
Returns/Cancellations after the item has shipped will also incur a 15-25% fee charged to you, as freight costs can be high for our products.
If your return is outside of the 30 day return period, your item will not be accepted.
You can always contact us for any return questions at sales@buildthepower.com.
Damages and issues
Please inspect your order upon reception and contact us immediately if the item is defective, damaged or if you receive the wrong item so that we can evaluate the issue and make it right.
Items that are damaged must be communicated to us within 24 hours of receiving the item.
Please note that if items have been taken out of the packaging and/or installed, returns may be voided depending on the manufacturer.
Some of our manufacturers do not accept returns for specific items, this must be considered when purchasing.
Exchanges
The fastest way to ensure you get what you want is to return the item you have, and once the return is accepted, make a separate purchase for the new item.
Refunds
We will notify you once we’ve received and inspected your return, and let you know if the refund was approved or not. If approved, you’ll be automatically refunded on your original payment method. Please remember it can take some time for your bank or credit card company to process and post the refund too.
You can contact us using the methods below.
US Customer Support Number: +1 507 636 3614
Email: sales@buildthepower.com
