Once the batteries are conditioned if the problem still exists then it sounds to me like the problem may be either with the motor or speed controller. In my experience it is more likely that this type of problem is with the motor. If the motor has been used for going uphill for a while then its permanent magnets may be wearing out and causing the motor to not provide as much power as it used to.
Thank you for your rapid response.
Should it be the permanent magnets will the motor have to be replaced??
If the permanent magnets have failed then the entire motor will need to be replaced.
Before replacing anything that is expensive I would condition the batteries and then also have the batteries load tested at a local battery store to make sure that they are not causing the problem.
Sometimes brand new batteries can be defective. The first thing I would do is individually load test each battery to verify that they are all working properly. You could us an automotive load tester for this at home, or bring them into a battery store like Batteries+ or an auto parts store and have them load test them for you. If any of the batteries are defective then they will need to be replaced. If the batteries all test good then you can rule them out as being the problem. I do not have any experience working on Lepton Oxygen scooters so unfortunately I can not offer any advise on its trouble codes or where to purchase replacement controllers for them.
My electric tricycle was losing power on the hills so thought the battery was getting weaker so invested in a new battery. Unfortunately, it didn't help and now it's very difficult going uphill. It seems to be getting weaker every time use it. Always recharge the battery after each use. The trottle doesn't seem to speed her up as it first did. Any solutions?