Altronix BT1240 Sealed Lead Acid Rechargeable Battery 12VDC 40AH
Overview
The Altronix BT1240 is a sealed lead acid (SLA) rechargeable battery rated at 12VDC and 40AH — a high-capacity standby power option for commercial security systems where extended runtime during a power outage is not optional. At 31.45 lb and packaged in an 8.50 × 7.70 × 7.80 inch footprint, this is a full-size SLA cell designed to drop into Altronix enclosures and power supplies that specify a 40AH battery, delivering hours of backup across access control panels, alarm systems, CCTV power supplies, and similar low-voltage security infrastructure.
For integrators specifying Altronix power distribution and battery backup systems, the BT1240 is the correct battery when the job spec calls for 40AH capacity — not the smaller 7AH or 12AH cells used in compact enclosures, and not the larger multi-battery arrays used in high-channel NVR or elevator applications. Get the AH wrong and you either waste enclosure space or fall short of the runtime calculation your system design is based on.
Key Features
- 40AH Capacity: At 40 amp-hours, this battery sustains meaningful loads for extended periods — useful when your access control or alarm panel must hold through a multi-hour outage without nuisance trips or door-lock failures. A panel drawing 2A continuously gets roughly 16–18 usable hours before the battery drops to its discharge floor.
- 12VDC Nominal Voltage: Matches the standard 12V battery bus used across the Altronix power supply lineup, including multi-battery enclosures and charging boards. No voltage conversion required — install and wire directly to the battery leads on a compatible Altronix unit.
- Sealed Lead Acid (SLA) Chemistry: SLA requires no electrolyte maintenance, no watering, and produces no free gas under normal float charge conditions — which means it can be installed in an indoor equipment closet or rack enclosure without special ventilation provisions that vented wet-cell batteries would require.
- 31.45 lb Weight: This is a full-size industrial SLA cell, not a compact insert. Factor the weight into your enclosure mounting plan — a wall-mount power supply housing two BT1240s exceeds 65 lb loaded, which affects both the wall anchor specification and the two-person install requirement.
- 8.50 × 7.70 × 7.80 Inch Form Factor: Confirm these dimensions against your enclosure's battery compartment before ordering. Altronix publishes compatible enclosure pairings — the BT1240 is designed for larger Altronix housing units, not the compact ALTV series or small-footprint access power supplies.
- Rechargeable / Float-Charge Ready: SLA chemistry is optimized for float-charge operation, the charging topology used in virtually all Altronix power supplies with integrated battery charging. The battery accepts a constant float voltage and maintains charge indefinitely when the AC supply is healthy, switching to discharge only during an outage.
- Country of Origin — China: Noted for procurement teams with country-of-origin requirements. Verify against your project's applicable compliance standards before specifying for government or federally funded installations.
Integration and Compatibility
The BT1240 is part of the Altronix battery family and is designed for use with Altronix power supplies and chargers that accept a 40AH, 12V SLA battery. Before ordering, cross-reference the battery compartment dimensions (8.50 × 7.70 × 7.80 in) and terminal type against your specific Altronix enclosure model — not all large Altronix enclosures accommodate a battery this size, and some specify multiple smaller cells instead.
For installations requiring reliable physical security system uptime, pairing this battery with a compatible Altronix charging supply ensures the battery remains at full capacity and is replaced on a regular maintenance schedule (typically every 3–5 years for SLA cells in float service, depending on ambient temperature). Higher ambient temperatures — above 25°C — accelerate SLA aging and reduce effective capacity between service intervals.
This battery is not intended for deep-cycle or high-rate discharge applications. SLA chemistry in standby service performs best when it rarely discharges below 50% capacity. If your load analysis shows frequent deep discharges due to recurring outages, consider a higher-AH configuration or a redundant supply to limit how far the battery drains during each event.
For multi-camera or large-panel NVR and recording system installations where total system backup runtime must be calculated across multiple loads, verify that the BT1240's 40AH rating is applied against the actual combined draw of all connected devices — access control readers, door hardware, sensors, and any auxiliary loads all factor into runtime.
Frequently Asked Questions
Q: What chemistry is the Altronix BT1240, and does it require any special ventilation?
A: The BT1240 uses sealed lead acid (SLA) chemistry. Under normal float-charge conditions it produces no free gas and requires no special ventilation, making it suitable for indoor equipment closets and rack enclosures.
Q: What is the rated capacity of the BT1240, and how long will it power a typical access control panel?
A: The BT1240 is rated at 40AH at 12VDC. A panel drawing approximately 2A continuously would have roughly 16–18 hours of usable runtime before the battery reaches its discharge floor, though actual runtime varies with load and ambient temperature.
Q: How much does the BT1240 weigh, and are there mounting considerations I should know about?
A: The BT1240 weighs 31.45 lb. If your enclosure specifies two batteries, the loaded enclosure weight exceeds 65 lb — plan accordingly for wall anchors and consider a two-person installation.
Q: What are the physical dimensions of the BT1240?
A: The BT1240 packages at 8.50 in (L) × 7.70 in (W) × 7.80 in (H). Confirm these dimensions against your Altronix enclosure's battery compartment specification before ordering.
Q: Is the BT1240 compatible with all Altronix power supplies?
A: The BT1240 is designed for Altronix power supplies and enclosures that specify a 40AH, 12V SLA battery. Not all Altronix enclosures accept a battery this size — some use multiple smaller cells. Always cross-reference your enclosure model's battery specification before ordering.
Q: What is the country of origin for the BT1240?
A: The BT1240 is manufactured in China. Verify against your project's country-of-origin or compliance requirements before specifying for government or federally funded installations.
The BT1240 comes up regularly on commercial access control and alarm jobs where the power supply spec sheet calls out a 40AH battery and the integrator needs to verify they're ordering the right cell — not a 7AH that fits the shelf but can't sustain the load, and not a 55AH that won't close the enclosure door. At 31.45 lb and a nominal 12VDC, the BT1240 fills that role for mid-to-large Altronix enclosures running continuous float charge.
Technical Highlights:
- 40AH Capacity: Enough reserve for multi-hour backup on moderate-draw panels — at 2A load, you're looking at 16–18 usable hours before hitting the SLA discharge floor, which covers most regional outage scenarios without requiring a generator cutover.
- SLA Chemistry: Sealed construction means no electrolyte maintenance and no gassing under normal float conditions — you can install this in a finished IT closet without venting provisions, which matters on commercial tenant build-outs where the MER is not a dedicated battery room.
- 8.50 × 7.70 × 7.80 in Package: These are the dimensions that determine whether this battery physically fits your Altronix enclosure. Cross-check against the enclosure's battery compartment spec before your truck rolls — a wrong-size cell on arrival is a same-day delay you don't need.
Deployment Considerations:
- At 31.45 lb, a dual-battery enclosure installation is a two-person job. Mark this on your labor estimate and include it in the site survey notes — wall anchors need to be spec'd for the full loaded enclosure weight, not just the housing.
- SLA service life in float-charge service typically runs 3–5 years depending on ambient temperature. Installations in unconditioned spaces — mechanical rooms or outdoor-rated enclosures in hot climates — will hit the low end of that range. Build a battery replacement line into your service contract accordingly.
This battery is the right call for commercial intrusion or access control jobs using mid-to-large Altronix enclosures where the AH spec is explicit and the runtime calculation has been done against the actual load — not as a generic standby cell dropped in without a backup runtime analysis.
