I bought the new style batteries for my mother-in-laws older modle mini jazzy that have a 1 year guarantee and are expected to last 2 to 3 years. It's been 3 months now and I'm already having issues that came on suddenly without warning (which the old style batteries always let you know when they were about to go). My thoughts are that this may be an electrical problem either in the control box or possibly a short somewhere in the system. I know the control boxes are expensive but don't want to have to keep replacing batteries every few months so I would like to get any advise on what could be causing this problem and how I can resolve it. Is there any special place I should look for a short? Should I take apart the control box and look for anything that seems off? I am not an electrician but I am totally capable of troubleshooting and even repairing a problem if I can find out what it could be. My mother in law is in a nursing care facility and dependent on this chair. I've tried to buy her a new one but she's very attached to this old, outdated silly contraption so I need to get it back up and running for her. Can anyone give me any tips on what could be the problem and where to look for them? I would be very grateful for any info and help that I can get as I don't have a truck to take the chair to a shop to get it looked at. Thank you in advance for any help you can give me. Deborah

Deborah,
The most common problem for this power chair involves the connections at the rear of the chair for the VSI controller (joystick). Unplug the large and small electrical connectors at the rear of the chair and inspect for discolored and corroded pins on the plugs. You can clean the flat pins on the large connector with a green synthetic scour pad and WD40. Spray contact electrical contact cleaner on the other pins and plugs.
Check the voltmeter on the back to make sure it is indicating charging. If not, remove the the rear cover and look for a black boot over a fuse holder. Inspect the fuse (7.5 amp ATO) to see if it is good. The on-board chargers on these chairs have a history of going bad, but are easy to replace. That being said, if you have good battery connections, good charger fuse, good cord connections, good voltage meter, then your most likely culprit is your on-board charger. The least expensive and easiest fix is to buy an off board charger and plug it in the front of the VSI (leave the old on-board one in the chair and don't plug in the AC cord).
Check the battery connections to make sure they are tight. Check the charger cord and make sure it is plugged all the way in.
If you have access to a voltmeter you can make electrical checks on all components. For now, I would check the obvious visually and mechanically. The connectors on the rear of the chair coming from the VSI are usually the source of most problems. Hope this helps.