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Replacement Batteries for Emergency Lighting
Last updated: November 2026
Quick Answer: Emergency lights and exit signs with sealed lead acid backup use a small number of standard battery sizes. The 6V 4.5Ah battery with F1 terminals is by far the most common. Larger units step up to 6V 7Ah or 6V 12Ah, and high-output, remote-head and central systems use 12V batteries from 7Ah up to 26Ah. To replace one, match the voltage, terminal type and case size printed on the old battery, then match or slightly exceed its amp-hour rating.
This guide is written for facility managers, electrical contractors and maintenance teams who replace emergency light batteries across whole buildings. It covers the standard sizes, how to read a battery label, and how to plan replacements so every fixture passes its annual test. Shop AJC® emergency light batteries.
Emergency Light Battery Size Chart
These are the SLA battery sizes AJC® makes for emergency lighting, with an example fixture battery each one replaces. Prices are at the time of writing.
| Size | Terminal | Dimensions (L x W x H) | Typical use | Example replacement |
|---|---|---|---|---|
| 6V 4.5Ah | F1 | 2.76 x 1.85 x 3.98 in | Two-head wall units, combo exit/emergency signs | Lightalarms RCL3000, Hubbell 1200005 ($8.39) |
| 6V 5Ah | F1 | 2.76 x 1.85 x 3.98 in | Same case as 4.5Ah with more capacity | Dual-Lite EZ-2 ($9.79) |
| 6V 7Ah | F1 | 5.94 x 1.34 x 3.74 in | Higher-wattage two-head units | Lithonia LHQM ($11.99) |
| 6V 12Ah | F1 | 5.94 x 2.01 x 3.7 in | Units with remote heads or longer runtime | Sure-Lites XR5 ($19.99) |
| 12V 7Ah | F1 or F2 | 5.94 x 2.56 x 3.7 in | 12V emergency units and remote-capable fixtures | Concealite 30202 ($19.39; 8Ah and 9Ah options) |
| 12V 10Ah | F2 | 5.94 x 3.9 x 3.78 in | High-output 12V units | Power Source WP9-12 ($36.69; 12Ah and 14Ah options) |
| 12V 26Ah | Nut and bolt (NB) | 6.5 x 6.89 x 5 in | Large remote-capacity units and small central systems | Dual-Lite 12-749 ($75.69) |
Don't see your fixture? Search the emergency light battery collection by the part number on your old battery or fixture. It covers Lithonia, Dual-Lite, Lightalarms, Sure-Lites, Hubbell, Concealite, Exitronix, Big Beam and many more brands.
How Do You Read an Emergency Light Battery Label?
The label on the old battery gives you almost everything you need. Look for these five details.
Voltage
Emergency light batteries are 6V or 12V. Voltage must match exactly, because the fixture's charger and lamps are designed for one or the other.
Capacity (Ah)
Amp-hours tell you how much energy the battery stores. The fixture maker chose that capacity so the lamps run for the required time, which is 90 minutes in most US buildings. Match it, or step up within the same case size, for example 4.5Ah to 5Ah. Never go lower.
Terminal type
F1 terminals are flat spade tabs 0.187 in wide, and F2 tabs are 0.250 in wide. Most 6V emergency batteries use F1. Larger 12V batteries may use F2 or nut and bolt (NB) terminals. The fixture's leads are sized to one type, so match the original.
Case size
Emergency light batteries sit in a bracket or strap with little spare room. Check the length, width and height against the size chart before you order a different capacity.
Date code
Many batteries carry a manufacturing or install date. If yours doesn't, write the install date on the new battery with a marker. That one habit makes a building-wide replacement schedule possible.
How Do You Plan Emergency Light Battery Replacement for a Whole Building?
Replacing batteries one failed fixture at a time means repeat ladder trips, emergency orders and failed annual tests. A simple plan avoids all three.
- Survey every fixture. Record the location, fixture brand and model, battery size and terminal type, and the install date if known. A spreadsheet is enough.
- Group by battery size. Most buildings use only two or three sizes, often 6V 4.5Ah plus one larger size. Grouping tells you exactly what to order.
- Set a replacement cycle. SLA emergency batteries typically last 3 to 5 years in normal indoor conditions, and less in hot mechanical rooms, warehouses and outdoor housings. Many facilities replace them on a fixed 3 to 4 year cycle instead of waiting for failures.
- Replace in batches. Swap a floor or building at a time and date every new battery. Turn off the fixture's branch circuit before opening it, remove the black (negative) lead first, and connect the red (positive) lead first on the new battery.
- Charge, then test. Give each fixture 24 hours on AC power before testing it. Then run the monthly 30-second test and record the results.
- Keep a few spares. Stock one or two batteries of each size for fixtures that fail between cycles.
For step-by-step swap instructions, see our emergency light battery replacement guide.
What Testing Do Emergency Lights Need?
In the US, most jurisdictions follow NFPA 101, the Life Safety Code, for emergency lighting. Section 7.9.3 requires a functional test of at least 30 seconds every 30 days and a test of at least 90 minutes once a year for battery-powered units, with written records kept for the authority having jurisdiction. A battery that can't carry the fixture for the full 90 minutes needs replacing. Check your local code for any additional requirements.
Why Choose AJC® Emergency Light Batteries?
AJC® batteries are compatible replacements, built to the voltage, capacity, terminal and case dimensions of the original part. They are not made by the fixture manufacturer.
- AGM construction: sealed, spill-proof and maintenance-free, designed for years of float charging in standby equipment.
- UL Recognized Component: as listed on each AJC® emergency light battery product page.
- Low cost per fixture: the common 6V 4.5Ah size costs $8.39 at the time of writing.
- Backed by a 12-month warranty and 30-day returns.
Can You Order Emergency Light Batteries in Bulk?
Yes. The AJC® wholesale battery program is built for facility and contractor orders, typically over $1,000. It offers Net 30 terms and tax-exempt account setup, with approval usually in less than 24 hours. We also supply hospitals and medical facilities and government agencies.
What Should You Do With Old Emergency Light Batteries?
Never put lead acid batteries in the trash. Take them to a battery retailer, auto parts store or local recycling center. You can also ship used SLA, VRLA and AGM batteries to us for recycling; see our battery recycling page for packing and shipping instructions.
Frequently Asked Questions
What is the most common emergency light battery size?
The 6V 4.5Ah sealed lead acid battery with F1 terminals, measuring 2.76 x 1.85 x 3.98 in. It fits most two-head emergency lights and combination exit signs that use an SLA battery.
Can I use a 6V 5Ah battery instead of a 6V 4.5Ah?
Yes. The 6V 5Ah battery uses the same case and F1 terminals as the 6V 4.5Ah and adds a little runtime. Voltage and terminals must still match.
What does NB mean on a battery?
NB stands for nut and bolt. The battery's terminals take a bolted ring connector instead of a push-on spade tab. You'll find NB terminals on larger batteries, such as the 12V 26Ah used in high-capacity emergency units.
Can I store spare emergency light batteries?
Yes, for a limited time. SLA batteries slowly self-discharge on the shelf, so store spares somewhere cool and dry, and install or recharge them within about six months. Fixture makers such as Lithonia treat emergency batteries as perishable and recommend charging them within six to twelve months of manufacture.
Are AJC® batteries the same as the original?
They are compatible replacements, not OEM parts. Each AJC® battery matches the original's voltage, capacity, terminals and dimensions. You re-use your fixture's existing leads and hardware.
Find Your Emergency Light Battery
AJC® makes replacement batteries for thousands of emergency lights and exit signs. Shop emergency light batteries, browse all AJC® sealed lead acid batteries by size, or call (888) 959-0103 for help matching a part number or quoting a building-wide order.