My uncle purchased a Kite 4 electric mobility scooter about 18 months ago and did not use it much before it was effectively put into storage in the garage. While it was in storage the batteries were never charged. In addition to this they were already 3-4 years old. Unfortunately they deteriorated to such a point that when i dismantled the battery module and checked the voltage of each of the batteries they had dropped to between 6 and 7 volts each. I used a smart charger to try to recover the batteries but this was unsuccessful. I tried using a DIY constant current charger to boost the batteries and then tried the smart charger again but this did not work either. My uncle rightly decided that it would be safer to purchase new batteries.
The batteries used on the scooter are 2 x 12V, 12Ah Sealed Lead Acid(SLA) types contained in a plastic case removable from the scooter. The scooter itself can be dismantled into 4 pieces to allow transporting in a car. The small round plastic cover on the front of the case is where the battery charger plug is connected to charge the batteries.
Here the old batteries have been removed from the case revealing the internal wiring and the metal contacts that connect the battery pack to the contacts in the scooter body. The middle contact connected to the green wire provides the 'inhibit' signal to the control electronics on the scooter allowing the batteries to be charged while the battery pack is still installed in the scooter.
In this picture the batteries have been installed and the connections to the battery terminals made. The safety fuse for the the batteries is installed in the wire that connects the +ve and -ve terminals of the two batteries together. The fuse is a blade type used in automotive applications. The black plastic connector at the front connects to a corresponding connector on the top cover which connects the charger socket to the batteries.
This picture shows the underside of the case where the connections of the battery are brought out and exposed to make contact with a corresponding set of contacts in the scooter.
This is the replacement battery before installation. The battery voltage was checked before being installed to ensure it was at a good level. Scooter batteries should always be purchased from a reliable source as they have to match the charger to be used to charge them and be approved for air travel.
In this picture the batteries have been installed and the wiring connected. When the top cover had been installed the voltage present at the charger socket and the contacts on the underside were tested and verified to ensure they were correct. The battery was now ready to be re-installed on the scooter.