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EcoFlow DELTA Pro Ultra X Extra Battery | 6kWh

EcoFlow DELTA Pro Ultra X Extra Battery | 6kWh
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$3,299.00
$3,299.00 - $3,299.00
$3,299.00
$2,399.00
$2,399.00 - $2,399.00
$2,399.00
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EcoFlow DELTA Pro Ultra X Smart Extra Battery
6kWh LFP · Expands to 61.44kWh Per Inverter · 5-Year Warranty

EcoFlow DELTA Pro Ultra X Smart Extra Battery

This is the expansion battery for the DELTA Pro Ultra X system: 6kWh of EV-grade LiFePO4 storage per unit, in a plug-and-play module that connects to a DELTA Pro Ultra X inverter without tools or an electrician. Add batteries as your needs change — up to ten per inverter, for 61.44kWh on a single inverter.

Because the Ultra X inverters themselves run up to three in parallel, the full system scales to 180kWh and 36kW of output. Each battery carries dual battery management systems with three-level protection, and EcoFlow backs it with a 5-year warranty. Renewable Outdoors is an authorized EcoFlow dealer — call us and we'll help you size the bank to your actual backup goals rather than guessing.

EcoFlow DELTA Pro Ultra X Smart Extra Battery
5-Year Warranty
Lowest Price Guarantee
Authorized EcoFlow Dealer
Free Shipping
0% APR Financing
Expert Support: (303) 876-7654

Why Add an Ultra X Battery

6kWh Per Battery

Each unit adds 6.14kWh of usable LFP storage — roughly a full evening of household load, or considerably longer on essential circuits only.

Up to 61.44kWh Per Inverter

Connect as many as ten batteries to a single DELTA Pro Ultra X inverter, and up to 180kWh across three inverters in parallel.

Plug-and-Play Expansion

Adding a battery doesn't mean rewiring your system — the connection cable is included and the inverter recognises the new capacity automatically.

Dual BMS, 3-Level Protection

Two independent battery management systems and three layers of protection monitor cell health, temperature, and current continuously.

EV-Grade LFP Cells

Lithium iron phosphate cells of the type used in electric vehicles — a chemistry chosen for thermal stability and long cycle life over peak energy density.

Stackable Footprint

Batteries stack vertically, so growing the bank costs height rather than floor area — useful in a garage or utility room.

What's Included

EcoFlow DELTA Pro Ultra X Smart Extra Battery

In the Box

  • 1 × DELTA Pro Ultra X Smart Extra Battery (6.14kWh)
  • 1 × battery connection cable
  • User manual
  • Warranty card

This is an expansion battery, not a standalone power station. It requires a DELTA Pro Ultra X inverter to function — if you're starting a system from scratch rather than expanding one, look at the DELTA Pro Ultra X Whole-Home Backup Power bundles instead.

DELTA Pro Ultra X Battery Specifications

Capacity 6,144Wh (6.14kWh) per battery — EcoFlow markets this as 6kWh
Nominal Voltage 102.4V
Cell Chemistry EV-grade LiFePO4 (LFP)
Battery Management Dual BMS with 3-level protection
Max Batteries Per Inverter 10 (61.44kWh per inverter)
Max System Capacity 180kWh with 3 inverters in parallel
Dimensions 26" × 18" × 8"
Weight 111.3 lbs
Operating Temperature −4°F to 113°F
Installation Plug-and-play; stackable
SKU EFDELTAPROUXEB
Warranty 5-Year Limited Warranty

You may see this battery quoted as either 6kWh or 6,144Wh. 6kWh is the round figure EcoFlow advertises; 6,144Wh is the precise nameplate rating, and it's what the per-inverter and whole-system totals are built from (10 × 6,144Wh = 61.44kWh).

Documentation & Downloads

DELTA Pro Ultra X User Manual (EcoFlow)

This links to EcoFlow's own manuals library for the DELTA Pro Ultra X system, which covers the inverter and the extra battery together. We've linked the library page rather than the PDF file directly because EcoFlow serves the manual from a content CDN whose file paths change between revisions — the library page will always point at the current version.

5-Year Warranty

Every Ultra X battery we sell is backed by EcoFlow's full 5-year limited manufacturer warranty.

Lowest Price Guarantee

Found it cheaper elsewhere? Call us at (303) 876-7654 before you buy.

Authorized EcoFlow Dealer

Genuine EcoFlow hardware, full manufacturer support, and honest sizing advice from our team.

EcoFlow DELTA Pro Ultra X Battery: Frequently Asked Questions

Can I use this battery on its own?
No. This is an expansion battery for the DELTA Pro Ultra X system — it has no inverter or AC outlets of its own and needs a DELTA Pro Ultra X inverter to work. If you're building a system from scratch, start with one of the DELTA Pro Ultra X bundles that includes the inverter.
How many batteries can I add?
Up to ten batteries per DELTA Pro Ultra X inverter, which comes to 61.44kWh on a single inverter. Because up to three inverters run in parallel, the full system ceiling is 180kWh and 36kW of output.
Will it work with my older DELTA Pro Ultra?
The Ultra X and the original DELTA Pro Ultra are different generations, and this battery is specified for the Ultra X. If you have an original DELTA Pro Ultra, the matching part is the DELTA Pro Ultra Battery Pack — call us at (303) 876-7654 before ordering and we'll confirm which one your inverter takes.
How long will 6kWh actually run my house?
At a 1kW average draw — lights, fridge, internet, electronics — one battery gives you roughly 6 hours. Add central air conditioning or electric heat and that drops to an hour or two. Most whole-home backup customers end up with two or more batteries; tell us what you want to keep running and we'll do the arithmetic with you.
Do I need an electrician to add a battery?
Adding a battery to an existing Ultra X system is designed to be plug-and-play — the connection cable is included and no AC wiring is involved. The original installation of the inverter and any transfer switch or home panel is the part that needs a licensed electrician.
How long will the battery last before it needs replacing?
It uses EV-grade LiFePO4 cells — a chemistry chosen specifically for long service life and thermal stability — and EcoFlow backs it with a 5-year warranty.
Can it be installed outdoors or in an unheated garage?
The battery is rated for operation from −4°F to 113°F, which covers an unheated garage in most climates. It isn't sealed against water, though, so keep it indoors or in a sheltered location rather than exposing it directly to rain or snow.
Does it charge from solar?
Yes, through the system rather than directly. The battery has no solar input of its own — the DELTA Pro Ultra X inverter handles solar, grid, and generator charging, and distributes that charge across every battery connected to it.
How much does it weigh, and can one person move it?
It's 111.3 lbs, so plan on two people for positioning and lifting it into a stack. Sort out placement before it arrives — this isn't a unit you'll want to reposition casually once it's connected.
Do you offer financing or price matching?
Yes. We offer 0% APR financing options through Affirm at checkout, and every purchase is backed by our Lowest Price Guarantee — if you find a better price elsewhere, call us at (303) 876-7654 before you order.
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