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FIRMAN · Expansion battery

B104201

Expand your backup power with the FIRMAN Zero-E Battery expansion pack. Adding 1,040Wh of capacity to your FIRMAN Zero-E Energy Storage System, this slide-lock battery connects effortlessly—just slide it into place until

1,040Wh capacityBattery

$499.99

$849.99

Direct price snapshot
FIRMAN Zero E Expansion Power Pack +1000
Official product image: FIRMAN

Core specifications, simplified.

01 · Stored power

1,040Wh

Rated battery capacity

02 · Runtime & operation

Manufacturer runtime

Runtime varies by load

Operating volume

Silent battery power

Fuel tank

No combustion fuel

03 · Size & ownership

28.6

Unit weight

15.4x10.6x8.3

Unit dimensions

Warranty
3-year warranty
Certifications
CARB · CETL · EPA
Availability
Available
04 · Controls & safety

Starting

Push-button power

Power quality

See specifications

Safety

Low-oil status listed below

Electrical

See full specifications

100W × USB-C PD Watts · 100W × USB-C PD Watts · Yes × USB-C PD In&Out 100W

These manufacturer images may include dimensions, control-panel callouts, included equipment, safety features, and common use cases. Scroll sideways to view the complete set available for this model.

FIRMAN B104201 product view
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Every official field, organized.

The technical fields below come from FIRMAN’s model-specific specification file. Product photos and infographics come from the official product gallery. Confirm current documentation before purchase.

Outdoor use only for combustion models. Never operate a fuel-burning generator inside a home, garage, shed, or other enclosed space. Follow FIRMAN’s manual and use an approved transfer method for home connections.

Manufacturer overview

Expand your backup power with the FIRMAN Zero-E Battery expansion pack. Adding 1,040Wh of capacity to your FIRMAN Zero-E Energy Storage System, this slide-lock battery connects effortlessly—just slide it into place until it clicks. Stack up to 10 batteries for a total capacity of 11,440Wh, giving you serious energy for extended outages or off-grid use. Charge it independently or as part of your Zero-E system. An onboard 100W USB-C port powers laptops, tablets, phones, drones, and more. Built with Lithium Iron Phosphate technology, the Zero-E Battery delivers safe, reliable performance with over 4,000 charge cycles. Whether you're preparing for emergencies or powering adventures, this expansion pack keeps you going longer. The FIRMAN Zero-E Energy Storage System delivers clean, emission-free power wherever you need it—perfect for homes, apartments, RVs, and vehicles. With 4,000 starting watts and 2,000 running watts, the Zero-E can power small to medium appliances, electronics, and essential devices. Featuring advanced EPS (Emergency Power Supply) pass-through technology, the Zero-E automatically backs up your fridge, modem, sump pump, or security system during an outage—switching to battery power in milliseconds. Its Lithium Iron Phosphate battery ensures safe operation, 4,000+ charge cycles, and long-term reliability. Need more runtime? Easily expand with slide-on Zero-E batteries—up to 10 add-ons for a total of 11,440Wh capacity. Power up your devices with six 120V outlets, a TT-30R RV outlet, four USB-A ports, two 100W USB-C ports, a 12V cigarette outlet, a 12V DC port, and a Qi wireless charger. Recharge the Zero-E your way: from a standard wall outlet, your vehicle’s 12V socket, or up to 400W of solar input. Whether you're preparing for emergencies or living off-grid, the Zero-E is your all-in-one portable power solution.

Certifications

cETLus (UL2743)
Yes
UN38.3
Yes
FCC SDOC
Yes
FCC ID
No
IC ID
No
DOE
No
CEC
No
SDS
Yes
ROHS
Yes

Main Unit

Rated Capacity
1040Wh
Cycle Life
>4000 complete cycles to 80% capacity
Storage Temperature
-20 ~ 40 °C (-4 ~104 °F)
Discharging Temperature
-20 ~ 40 °C (-4 ~104 °F)
Charging Temperature
0 ~ 40 °C (32 ~104 °F)
Shelf Life
12 Month

Input

AC Charging Watts
400W
MPPT Watts
400W
Car Charging Watts
240W
USB-C PD Watts
100W

Output

USB-C PD Watts
100W

Control Panel

LED Level Display
Yes
Main Power Switch
Yes
USB-C PD In&Out 100W
Yes
XT60 DC Input
1
Expansion Pack Male Connector
Yes
Expansion Pack Female Connector
Yes
XT60 Cover
Yes

Frame

Pull Rod
Yes
Color
Black

Battery Pack&BMS

Battery Cell Spec
LI-FUN 25Ah 3.2V
Battery Type
LFP
Pack Configuration
13S1P
Cooling
NA
Rated Charging Current
35A
Rated Discharging Current
65A
Overcurrent Protection
Yes
Temperature Protection
Yes
Short Circuit Protection
Yes
Balance Management
Yes

Packaging

UPC Code
840876105016
Carton Dimensions
19.7x15x11.4
Carton Weight
31.5
Product Dimensions
15.4x10.6x8.3
Product Weight
28.6
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Official sources:FIRMAN product pageTechnical specificationsAll FIRMAN generatorsVerified September 15, 2026