Modern stairlifts almost universally use DC (direct current) battery power, even though they plug into standard household AC outlets. This seemingly counterintuitive approach offers significant advantages.

How the Battery System Works

The stairlift connects to a household outlet (110V in North America, 240V in the UK) via a transformer that steps down the voltage. This low-voltage power continuously charges a pair of 12V batteries located in the carriage (the moving part with the seat).

When you operate the stairlift, it runs on battery power — not directly from the wall. The batteries are recharged whenever the stairlift is parked at a charging point, typically located at both ends of the rail.

Why Batteries?

• Power outage operation: A fully charged stairlift can make 20-40 trips even without mains power — critical for elderly users during outages.
• Smoother operation: DC motors provide gentler starts and stops compared to AC motors, reducing jolt and improving comfort.
• Safety: Low-voltage DC power (24V) is inherently safer than mains voltage, reducing electrical hazard risks.
• Quieter operation: DC motors typically run more quietly than their AC counterparts.

The Motor

Stairlift motors are typically rated between 300-500 watts — similar to a small kitchen appliance. The motor drives a rack-and-pinion system (more on that in Rail Technology) that moves the carriage along the rail. Most motors include a worm gear that prevents the carriage from moving when power is off, acting as an automatic brake.

The rail (or track) is the backbone of any stairlift. It guides the carriage smoothly and safely along the staircase, supporting the weight of both the equipment and the user.

Straight Rails

Straight rails are extruded aluminum profiles — long pieces manufactured by pushing heated aluminum through a shaped die. This creates a consistent cross-section along the entire length. The profile includes:

• A gear rack (toothed strip) that the motor's pinion gear engages with
• Guide surfaces for the carriage's wheels to roll along
• Mounting points for securing to stairs or wall
• Cable channels for electrical wiring

Curved Rails

Curved rails are significantly more complex. They must be custom-manufactured to match the exact geometry of each staircase. Modern curved rails are typically produced using CNC (computer numerical control) bending machines that can achieve precise curves.

The manufacturing process begins with a detailed survey of the staircase, often using laser measurement or photogrammetry. This data is converted into a 3D model, and the rail is bent to match. A single curved rail may contain dozens of individual bends.

Rail Mounting

Rails can be mounted to the stair treads, to the wall, or to the staircase structure itself. Tread mounting is most common for wooden stairs, while wall mounting may be preferred for stone or when preserving stair surfaces is important. Heavy-duty installations may require structural mounting to supporting beams.

Modern stairlifts incorporate multiple layers of safety systems, many required by regulation and others added by manufacturers to exceed minimum standards.

Obstruction Sensors

Safety edges run along the bottom of the carriage and footrest. If the stairlift encounters an obstacle (a pet, a toy, a piece of luggage), these pressure-sensitive strips trigger an immediate stop. The stairlift will not move until the obstruction is cleared.

Seat Belt

All stairlifts include a seat belt, typically a simple lap belt similar to those in older automobiles. While stairlifts move slowly (around 0.15 m/s), the belt prevents users from sliding or falling, especially important for those with balance issues.

Swivel Lock

At the top of the stairs, the seat can typically swivel to face the landing, making it safer to stand. A lock prevents the stairlift from moving until the seat is returned to the forward-facing position, ensuring the user is properly seated before travel.

Overspeed Governor

A mechanical governor monitors descent speed. If the stairlift exceeds safe speed (due to motor failure or other malfunction), the governor engages a brake to stop the carriage immediately.

Key Lock

Most stairlifts include a key switch that disables operation, preventing unauthorized use — particularly important in homes with young children who might be tempted to "play" with the stairlift.

Stairlift controls are designed for ease of use, accommodating users who may have limited dexterity, vision, or strength.

Armrest Controls

The most common control method is a joystick or paddle mounted on the armrest. Push it one way to go up, the other way to go down. The control is "dead man" style — the stairlift stops as soon as you release it.

Remote Controls

Wall-mounted call stations at the top and bottom of the stairs allow family members to send the empty stairlift to a different floor. Wireless remote controls offer the same functionality in a portable form.

Smart Controls

Modern stairlifts increasingly offer smartphone apps and voice control integration. Users can summon the stairlift with Alexa or Google Assistant, and caregivers can monitor usage remotely.

Professional installation typically takes 2-4 hours for a straight stairlift and 4-8 hours for a curved model. Here's what the process involves:

Survey

A technician measures the staircase and assesses mounting options. For curved rails, this involves detailed measurements using specialized tools.

Rail Installation

The rail is secured to the staircase — typically every 2-3 steps for tread mounting. This requires drilling into wood or masonry, depending on the stair construction.

Carriage and Seat Assembly

The carriage is mounted on the rail and the seat assembly attached. Electrical connections are made, and the charging points at each end are installed.

Testing and Training

The installer runs multiple test cycles, adjusts safety settings, and trains the user on proper operation and basic maintenance.

Stairlifts are generally low-maintenance devices, but regular care extends their lifespan and ensures safe operation.

User Maintenance

• Keep the rail clean and free of dust/debris
• Ensure charging points are plugged in when not in use
• Listen for unusual sounds during operation
• Test the seat belt regularly

Annual Service

Professional servicing is recommended annually. Technicians check motor function, battery health, safety sensors, rail condition, and lubrication. Batteries typically last 3-5 years before replacement.