The lift is not used much and when I came to renew a toilet I decided it was the ideal way of carrying the old toilet down stairs however it only went one meter then stopped.At the time I did not have tools to try and repair and assumed it had been left off the charging point so hand wound back to charging point and left it.
One return it still did not work so went and got a few tools.
On removing front cover I found the spade connections on the replacement batteries fitter were smaller than the original battery and the Stenner approved engineer had used the insulated cover to hold the back of the spade connector pushed against the battery terminal. Using some pliers it was simple enough to make the spades grip correctly. Tested voltages supply 29.4 open circuit and battery off station 27.4 on station 27.6 so seems battery was charged. Banged every safety switch and still no luck. Removed both battery and mains supply the latter by winding off station and then all started to work.
However it seems odd to me that an intermittent battery connection would actually cause the chair to fail. One supply had been returned I would have expected it to resume working so lights were on so supply was there yet the chair had remained stuck one meter from top charging station likely after a bad connection had caused it to stop.
It seems likely there is a reset procedure but can't find what it is.
When it failed last time it was due to being left off station. In spite of winding it to station it did not work again until the Stenner engineer renewed the batteries. Clearly when he renewed the batteries he would have switched off all power which is what I did this time to get it working. So may be that is the re-set method. However with some one sitting in the seat one can't remove the front cover so if it locks its self out with my mother on the chair it would need a fire brigade rescue before I could reset chair which is clearly not what is wanted.
So any ideas of what may have caused failure and what is the reset method. There was nothing on the chair when it failed on the arm there are two lights a yellow one and a green one it would seem it will not run until we get green light.
The controls are wireless
and the leg must be down before the chair can be used. Since 
this leg if raised will stop the chair while travelling and there is no wired connection to the chair I must also assume a wireless link from leg to chair. So there is a possibility the fault could have been some EMC problem. The whole safety design seems flawed in that there are no sensors on the leg and it can't be seen from the top controls only indication on leg position is the sound of motor straining common sense would say the chair should still run with leg up and the user should be able to get to where they can see the leg before lowering it. After all taking the user to within two steps of bottom of stairs is safer than having them stuck at top of stairs so it would seem no common sense has been used it is simply how can we adapt the lift to fit the house. So there may be some safety which should have been removed but was left in place. With an official Stenner guy who can't even fit a battery correctly I am not inclined to call Stenner.
I do also question mounting batteries on their end. I know they are gel batteries but I have always in past seen them mounted with terminals on the top.