Sentinel™ indoor battery storage
Indoor lithium-ion battery storage enclosures and cabinets
A ventilated, monitored room for lithium-ion and LiFePO4 batteries, built inside the building you already operate. Fabricated in our Santa Rosa, California plant and designed and built to UL 1487 and NFPA 855 standards.
Sentinel™ indoor battery enclosures: walk-in rooms, rack-access enclosures and cabinets that separate lithium-ion inventory from the rest of your floor. Exhaust, detection, suppression and controls are installed and wired before the unit leaves our shop, so the work on your site is placement, connections and commissioning.
Built in-house: AEL is fully vertically integrated. Control panels, electrical, plumbing, HVAC and mechanical work, fire-suppression installation (dry chemical and clean agent systems), welding, sheet metal fabrication, powder coating and our own insulated wall panels are all produced by our own team. AEL is also an approved Stat-X distributor. See our in-house capabilities.
Standards: designed and built to UL 1487 and NFPA 855 standards.
Indoor formats
Two ways to put battery storage inside a building.
Choose the format by how batteries move through your operation, not by battery count alone. A parts room that pulls two modules a day needs a different enclosure than a UPS refresh that stages forty at once.
Walk-in or rack access · grey or white
Indoor Sentinel
One product, laid out two ways: a walk-in room assembled from modular panels on your existing slab, where people and carts go inside, or a rack-access enclosure built around fixed racks and reached through the doors. Ventilation, detection and suppression are tied together either way, and the enclosure is finished in grey or white.
Cabinet · five published models
Sentinel Mini cabinet
Factory-built cabinets from 43 to 80 inches tall with published dimensions and pricing, for service, warranty and parts inventory that fits on shelves.
Know which format fits? Get a quote
Engineering scope
What goes inside the enclosure.
| Formats | Indoor Sentinel (walk-in or rack-access layout, grey or white); Sentinel Mini cabinet |
|---|---|
| Footprint | Built to the room and the battery layout |
| Battery types | Lithium-ion and LiFePO4; damaged or recalled packs reviewed separately |
| Wall construction | Modular wall panels, engineered and built in-house |
| Wall construction options | 1, 2 and 3-hour constructions available |
| Ventilation | Emergency ventilation ducted to the exterior, linked to gas detection |
| Detection and alarms | Early-warning gas and thermal detection, local alarms, emergency purge, tie-in to building systems |
| Suppression | Dry chemical, clean agent, Stat-X condensed aerosol or sprinkler connection |
| Controls | AEL CORE control panel, built to UL 508A, NEMA rated for indoor and outdoor installs; UL or ETL (Intertek) listed components |
| Charging | Charging battery storage add-on available |
| Racking | Battery racking engineered around your modules |
| Standards | Designed and built to UL 1487 and NFPA 855 standards |
Sentinel indoor enclosures are designed and built to UL 1487 and NFPA 855 standards. Your authority having jurisdiction approves the installation; we prepare the information they ask for:
- Enclosure layout, elevations and anchoring details
- Battery type, quantity and arrangement as provided by the owner
- Ventilation basis and exhaust discharge location
- Detection, alarm and suppression descriptions with equipment data sheets
- Electrical one-line and control-panel schedule
- Separation details and the selected 1, 2 or 3-hour construction
Batteries that are installed and running as an energy storage system, including in-service UPS strings, are evaluated under different standards. For those projects, see EnergyCube BESS enclosures.
AEL CORE CP2000 control panel, built to UL 508A, NEMA rated for indoor and outdoor installs
Every Sentinel ships with the AEL CORE control panel, built to UL 508A in our own panel shop and NEMA rated for indoor and outdoor installs. One familiar operator layout controls ventilation, lighting and emergency stop, with status shown at the door so anyone can check the room at a glance.
The tower light above the panel gives anyone walking up a one-glance answer: red means check airflow, amber with the horn means the room is purging, and no light means the system is normal. More on AEL CORE control panels.
Some inventories cannot sit at shipping charge for months: replacement packs that must be topped up before install, UPS modules held on a maintenance charge, fleet spares rotated back into service on a schedule. The charging add-on turns a Sentinel enclosure into a supervised charging and storage room, wired in the same shop that builds the rest of the unit.
- Dedicated charging circuits, receptacles or hard-wired charger connections, sized to the chargers you specify
- Charger mounting positions and cable routing laid out with the racking, so cords stay off the floor and out of the aisle
- Charging power can be tied into the AEL CORE control panel and cut on a gas, heat or ventilation alarm
- Exhaust and detection sized for the heat and off-gas of charging, not storage alone
- Charging scope written into the drawings and system descriptions for your AHJ review
Sentinel enclosures with the charging add-on are designed and built to UL 1487 and NFPA 855 standards. Send the charger make, model and quantity, the batteries being charged and the charging schedule, and we will size the electrical service and ventilation around them.
| Indoor Sentinel | Sentinel Mini cabinet | Outdoor Sentinel container | |
|---|---|---|---|
| Where it goes | Inside the building | Inside the building | Yard or pad |
| Access | Walk-in, or through the doors (rack access) | Through the doors, shelves | Walk-in |
| Best fit | Rack and pallet-scale inventory, staging, charging review, long-term rack storage | Service, warranty and parts stock | Large inventories where yard space exists |
| Sizes | Built to the room and the rack layout | Mini 30, 40, 60, 80 and 100 | 8×10, 8×20, 8×40 ft and custom |
| Pricing | Quoted per project | Published online | Quoted per project |
| Learn more | This page | Sentinel Mini | Sentinel containers |
An outdoor Sentinel container is still the simplest answer when there is yard space and room for separation. Indoor builds earn their place when:
- There is no yard, or the yard is leased, shared or already committed to parking and trailers.
- Batteries have to stay inside the secured building, under the same access control as the rest of the parts inventory.
- The batteries belong next to the work: a service bay, a UPS room, a battery lab or a pack-assembly line.
- Outdoor temperatures would push HVAC size and energy use well past what an interior room needs.
Going indoors shifts the engineering toward the host building: where the exhaust discharges, how alarms reach the building fire-alarm panel, how the sprinkler system is handled and what the slab can carry. Those questions come first in our review. For yard installations, see Sentinel walk-in battery storage containers.
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Battery and workflow review
Chemistry, module dimensions and weight, state of charge, new or damaged stock, charging or storage only, and how often batteries come and go.
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Host-building survey
Floor area, clear height, delivery path and door sizes, slab capacity, the exhaust route to the exterior, available electrical service, and the building fire-alarm and sprinkler systems.
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Drawings and AHJ package
Layout and elevations, equipment schedule, electrical and mechanical details, detection and suppression descriptions, and separation information for your fire-protection engineer and the authority having jurisdiction.
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Fabrication in Santa Rosa
Panels, framing, control-panel wiring and suppression hardware are built in our own shop, with factory testing documented to the project scope.
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Delivery and assembly
Modular panels let the room be assembled inside the building instead of craned into a yard.
Download the brochure (Sentinel sizes, specifications, included features and upgrades, PDF).
Have a room in mind? Get a quote for this configuration
Applications
Where indoor enclosures go.
Gallery
Indoor Sentinel configurations.
Indoor battery storage FAQ
Questions buyers ask before an indoor project.
Can lithium-ion batteries be stored inside a building?
In most jurisdictions, yes, but the quantity, the battery condition, the room construction and the protection systems all affect what your authority having jurisdiction will accept. NFPA 855 and, where adopted, the International Fire Code are the usual references. A dedicated enclosure designed and built to UL 1487 and NFPA 855 standards gives the reviewer a defined, documented space instead of open shelving in a general warehouse. Confirm quantity limits and separation requirements with your AHJ.
What standards are Sentinel indoor enclosures designed to?
Sentinel indoor enclosures are designed and built to UL 1487 and NFPA 855 standards. The installation itself is approved by your local authority having jurisdiction, and once your project is ordered, AEL supplies the drawings and system descriptions that review requires.
What is the difference between an indoor battery enclosure and a battery storage cabinet?
Access and scale. An indoor Sentinel room is walk-in: staff and carts go inside, and the racking is laid out around pallet- or rack-scale inventory. A Sentinel Mini cabinet is reached through its doors and suits shelf-scale service and parts stock. Both are designed and built to UL 1487 and NFPA 855 standards; the right one depends on how many batteries move in and out each day and how large they are.
How is an enclosure ventilated when it sits inside another building?
Exhaust always goes outside the host building, never into it. Our engineers design the emergency ventilation around your batteries and your building, and coordinate the discharge point with your mechanical engineer so occupied spaces stay safe.
Can the enclosure connect to our building fire alarm and sprinkler system?
Yes. The enclosure provides alarm and trouble outputs for your fire-alarm panel or BMS, and it can take a sprinkler connection where your fire-protection engineer specifies water. Where water is not wanted, dry chemical, clean agent or Stat-X condensed aerosol suppression can be installed instead.
Can batteries be charged inside an indoor enclosure?
Yes, with the charging battery storage add-on. Charging changes the design: it adds electrical load, heat, battery-management behavior and supervision requirements. Tell us at the start if you plan to charge, so circuits, ventilation, detection and the AHJ documentation are developed for charging rather than storage only. See the charging add-on.
Can damaged or recalled batteries share an enclosure with new stock?
Usually not without a separate plan. Damaged, swollen or recalled packs follow the battery manufacturer’s handling instructions and your safety team’s isolation protocol, which often means a dedicated enclosure or compartment. We configure the enclosure around the protocol you and your AHJ settle on.
What do you need from us to quote an indoor enclosure?
Battery spec sheets or SDS, module dimensions and weights, the maximum quantity on hand, whether stock is new or damaged, and whether you will charge. For the building: a floor plan or photos with dimensions, door and corridor sizes on the delivery path, ceiling height, available power and any comments already received from your AHJ or insurer. For service on an existing unit, see service and maintenance.
Get a quote
Send us the battery data and a floor plan.
We will review the layout, the systems the enclosure needs and the documentation your AHJ will ask for, then come back with a configuration and price. Prefer to talk it through? Call 888-502-6695.
- Built in-house: fabrication, electrical, controls and suppression by our own team.
- Approved Stat-X distributor.
- Factory testing, documented as specified.
Financing available. Explore equipment financing and leasing options
- Talk to an engineer (888) 502-6695
- Location 1402 Airport Blvd, Santa Rosa, CA 95403
- Hours Mon – Fri, 8AM – 6PM PT
Request received.
Thank you. An AEL representative will review your request and reach out to you soon.
Your inquiry:
What happens next
- Engineering review. An AEL engineer reads your request and checks it against the right product line.
- We reach out within one business day. By email or phone, to confirm scope, site conditions and timeline.
- Specs and pricing. You receive pricing and the key specifications for your configuration. Project drawings are prepared once an order is placed.