Power chair issues - needs advice

I see you brought it 2nd hand. Theres your first mistake. There will have been no guarantee, or insurance i expect. Even if you have insurance it won't cover batteries. It needs a good service and new batteries. Take it to a reputable mobility shop to get the work done
I see you live in the US - so can't help with telling you where. don't buy online. As has been said. LEAD batteries are damn heavy to courier and lithium ion ones are a class 9 risk (apparently)! So good luck finding a courier if you go that route.

Sorry for my late response. Much has been going on in the past month. I agree that parts for mobility aids are very high. Most likely because we are seen as a captive audience. It shouldn't be legal!

I finally had new batteries installed a couple of days ago. It was a challenge because the company from whom I ordered them had lousy customer service. First they were late getting sent out, then they sent just one, then I had to request the missing battery be sent.

Then they sent two, meaning the third one has to go back now!

Anyway, I took my powerchair for a short test run yesterday and all went well. I took it for a longer run today and it stalled out on me. I had to call some relatives to help me get home. I was scared!

I'm getting 7 flashing lights on the joystick, so if I'm not mistaken, that means there is a fault in the controller.

I don't think it's the batteries as they are new. But is it possible this could short out the batteries?

I did some shopping around online and found a couple of places where the price isn't too bad for a controller.

I would appreciate everyone's thoughts on this issue. Again, I apologize for my late response. Alot has been going on at home, much of which has not been good at all.

Thank you!

The flashing lights indicate its a connectivity issue. There's some wrong with the joystick or with the wiring from the joystick to the battery or to the motor.
A piecemeal approach won't work. You need to take the WHOLE thing to a dealer in mobility items. (You brought it 2nd hand so maybe look up the nearest dealer for the make?)
Hopefully they can diagnose and correct problem. The batteries havent shorted. One thing to check is: is the charger recharging the batteries correctly?

To disagnose the problem is to look at the manual and it will tell you the problem by which lights was flashing. If you havent got a manual download one by googling it.