My Hoveround mpv5 will not turn on charger states its full power

It sounds like the batteries have gone bad and need to be replaced.

The batteries contain a gel that needs to have current run through it on a regular basis (at least 8 hours once a week) or it will solidify. If you attach the charger, what will most likely happen is the green light will either stay green or go to green after a very short time. When you turn on the power chair, nothing happens. The charger will indicate the batteries are full, but instead of being full of pwer, they are full of crud. Your warranty will most likely not cover replacment as this is due to customer neglect, but your insurance may still cover the replacement if you can wait for the process to go through. Otherwise, you will need to replace the batteries on your own, type U1, 24v 33 amp, found at Batteries Plus, Insterstate Battery or any other battery warehouse for $75-120 each.
To replace the batteries:
Remove the black power cords behind the battery covers by squeezing the plastic pinch clip. Remove the cover carefully by unhooking the black webbing strap so that you do not yank any of the leads. Using a 7/16" wrench loosen the bolts that attach the leads to the posts, be careful if there is any corrosion that may irritate your skin. Check the fuses to make sure they are still good; if not they are regular automotive fuses that are inexpensive and can be found at any auto parts store. Remove the plastic caps or any packaging from the new battery posts and seat the batteries on the tray, connect the leads to the posts as indicated and tighten with the wrench. Place the batteries back ont he tray, reconnect the power cord, Replace the covers, and tighten the straps.
You may want to use the power chair until the battery is used up before you charge it fully for 8-12 hours; this will ensure that the battery gets FULLY cycled and any buildup inside the battery from it sitting on the shelf in the store is burned out. Make sure that you charge the power chair after a full day's use for 8-12 hours (overnight), not after every trip as overcharging can cause damage. If the power chair in not going to be used for a while, continue to charge the batteries at least one day a week to keep the batteries fluid.
Return your used batteries to the battery store or auto parts store for proper disposal. Good luck!