Difference Between AC and Battery Powered Stair Lifts

There are two kinds of power supplies for stair lifts. First, AC (alternating current) which are “wired” at all times and use a trailing power cable for their power supply. The second type is DC (direct current) which utilize a rechargeable battery. In the past AC supply was the the most popular type of stair lift. Today, with the constant improvement of battery technology, DC is the most popular. Because of this most people need assistance with DC supplied lifts.

What are the advantages of DC powered stair lifts?Because of the increased technology in batteries, nearly all stair lifts companies utilize this technology. These lifts are very easy to install and maintain.

Some stair lifts do not require their own dedicated power supply. The owner can plug the stair lift into a nearby outlet to charge the battery while it is not in use. The charger unit transforms the 120V supply down to 24-38V, which converts it to DC to feed the stair lift when the unit is on charge etc. All DC battery stair lifts will continue to operate even in the event of a power outage or blackout, this alone is important. It is reassuring to know that you will not get stuck in the middle of the stairs should an outage or emergency occur. Battery stair lifts can usually make 24 full runs Up/Down before the batteries are exhausted and require charging.

There are many ways of charging the stair lift battery. The most common approach is to have a fixed copper charging strip located at the top and bottom of the stair lift track. When the stair lift is driven to the top or bottom of the track the moving charger pick-up points located under the stair lift carriage make contact with the fixed copper charging strip and automatically charge the batteries. If the lift is not fully connected to the charger contact strip the lift normally emits a beeping noise to make the lift user aware of the fact that the lift is not in contact with the charger unit; or it has been accidentally switched off. If the lift is at the bottom or top and the charger unit is switched on, and the lift still emits an audible sound you need to contact your stair lift installer right away, so they can come and inspect your stair lift for defaults, or problems.

Some stair lift manufacturers have kept the AC electrical trailing flex cable design, although the cable is now carrying low voltage DC 24-38V. This enables the stair lift to be constantly charged, and eliminates the need for charger contact strips or pick-up points. The obvious advantage is that it doesn’t matter where you leave / park the stair lift; it is being charged at all times.

Both systems have there advantages and disadvantages. The system using the copper strip charging contacts requires more parts in the making of the lift, and periodic adjustment cleaning of the charger pick-up assembly unit. It also relies on the lift user to ensure the lift is correctly parked in the charging position

The lift using the constantly charged trailing cable system has more moving parts so more chance of something going wrong. Common faults are trailing cable getting jammed or broken wires in the cable itself. Both do the job equally well, and both systems will require adjustment or repair at sometime in the life of the lift.


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