Will it be 220V? If that's an option, that would be a good way to go. The lifts are naturally slow for safety, but I'm thinking 110V might be taxed out
As far as power source, I looked up the Acorn lifts (
https://www.acornstairlifts.com/stairlift/acorn-stairlifts ) and found that the "mains supply" is listed as "50-60Hz, 100-240V AC" while the "power supply" is listed as "24V DC (battery)".
To see that, click on "View Technical Details" after you select curved or straight stairlift under "Stairlifts" on that website.
Given that, I'd gather that the motor itself is run from a 24V battery (likely in the chair's base itself to minimize power loss), and the battery charges from the AC source.
Having a battery hopefully means that at least the lift would allow one to complete a trip up or down in the event of a power outage, but you would need to confirm that.
I would expect that other stairlift brands would be similar in that regard, but again, it would be good to confirm that with whatever make/model you go with.
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I know we had two stairlifts (I don't know the make/model) at one of my previous employers for one of the handicapped employees, and it worked well, though it was not fast.
Those stairlifts at my old company carried the person from the factory floor level to a mezzanine that was probably 15 to 20 feet (vertically) above the main floor, up single long staircases at either end of that mezzanine.
To the best of my knowledge, it was powered from a standard 110V-120V circuit.
The only issues I recall them having was when someone else who clearly exceeded the weight limit tried to use it, and damaged the drive.
Hope that helps.