How can I resolve my stairlift electrical problem?

[kenward]

I am an 80-year-old retired disabled senior citizen. About a month ago we purchased a used Ameriglide Horizon Stair Lift for our stairs to our lower level family room, because of my unsteadiness in walking, and several recent falls. We bought it from a neighbor two houses up from us and moved it in one piece. His wife whom he had it installed had died last year, and he wanted it taken out. it worked fine at his house. I rode it up and down a couple of times before we bought it and removed it. But when we installed it here, the in-line battery charger transformer apparently shorted out. It was a 24-volt transformer. The man we bought it from came over and installed a 29-volt transformer. Since then the unit displays an "overload" message on a small display screen when the unit is plugged in, and it beeps constantly. We hired a technician to come to check it out, and he said the problem is the transformer is to powerful. His company charged us $200.0 for just the trip from Chippewa Falls and $100.00 for the hour of work he put into checking it out. He called this morning and talked to Penny, and told her that the 24-volt transformer from Ameriglide is no longer being manufactured. He also said that any other 24 volt transformer may not work, because all 24-volt transformers don't do the same thing (which is kind of a mystery to me). Anyway, I'm wondering if some kind of technician could use resistors to reduce the voltage to the lower required level. I don't know enough about electricity to make that determination. Maybe you could suggest a type of electrical technician who could resolve this problem so I can use the lift. O, can I just continue to use the larger voltage charger, and turn it off at each end to stop the annoying beeping, without damaging the batteries.?

 

[Lucien Nunes]

There is a possibility of confusion between a power supply unit (aka transformer) intended to power equipment directly, and a battery charger that is purpose-designed to charge a battery. The key difference is that the output voltage of the power supply unit is constant, whereas the output of the charger is managed to suit the requirements of the battery. A 24V power supply would output 24V for a nominal 24V system, whereas a '24V charger' needs to output up to about 29V, although not continuously, to charge a 24V battery, since all batteries require a higher voltage to charge than their nominal.

A quick scan of the Horizon instructions suggests that the unit required is specifically a battery charger, presumably a conventional 24V charger of a size suitable for the capacity of the battery fitted to the lift, which I assume to be a lead-acid type. A constant 29V power supply would probably overcharge (the float voltage of a 24V lead acid is more like 27.5V).

Because the connection from charger to battery is made by a sliding contact in the track and possibly only at the end stations, some types of smart charger might overcharge because they would reset each time the lift moves, and restart the charge cycle. Therefore it is possible that even if the unit fitted is a 24V charger, the lift might still give an overcharge warning.

Can you post a picture of the data on the unit presently fitted?

 

[kenward]

There is a possibility of confusion between a power supply unit (aka transformer) intended to power equipment directly, and a battery charger that is purpose-designed to charge a battery. The key difference is that the output voltage of the power supply unit is constant, whereas the output of the charger is managed to suit the requirements of the battery. A 24V power supply would output 24V for a nominal 24V system, whereas a '24V charger' needs to output up to about 29V, although not continuously, to charge a 24V battery, since all batteries require a higher voltage to charge than their nominal.

A quick scan of the Horizon instructions suggests that the unit required is specifically a battery charger, presumably a conventional 24V charger of a size suitable for the capacity of the battery fitted to the lift, which I assume to be a lead-acid type. A constant 29V power supply would probably overcharge (the float voltage of a 24V lead acid is more like 27.5V).

Because the connection from charger to battery is made by a sliding contact in the track and possibly only at the end stations, some types of smart charger might overcharge because they would reset each time the lift moves, and restart the charge cycle. Therefore it is possible that even if the unit fitted is a 24V charger, the lift might still give an overcharge warning.

Can you post a picture of the data on the unit presently fitted?

No, the charging contacts are at the top end and bottom end of the rail, there is no sliding contact. The chair operates down and up between contacts only by battery power. The warning does not read overcharge". it reads "overload". So, can I just continue to use the 29-volt charger, or could that ruin the two 12-volt batteries?

 

[kenward]

No, the charging contacts are at the top end and bottom end of the rail, there is no sliding contact. The chair operates down and up between contacts only by battery power. The warning does not read overcharge". it reads "overload". So, can I just continue to use the 29-volt charger, or could that ruin the two 12-volt batteries?

The copper strip is the charging contact point at the top end of the stair-lift, there is another one just like it at the bottom end. There are no sliding contacts on the rail itself.