Can the hoveround batteries be charged with a trinkle charger?

Check Power and Connections:

Ensure the power is turned on.
Confirm that the charger and power cord are not plugged into the unit.
Make sure the brake release levers are in drive mode.
Joystick Controller:
Verify that the joystick cable is securely attached.
Check if the batteries are fully charged. If not, proceed with charging.

Battery Charger:
Plug the charger into a working outlet and test it with a lamp or LED clock.
Use a charger specifically designed for your Hoveround MPV5.
If the problem persists, consider replacing the battery charger.

Battery Issues:
Ensure the brake release levers are in drive mode.
Check all battery connectors to ensure they are properly connected.
Verify that the batteries are fully charged. If not, proceed with charging.
If the batteries still won't charge properly, replacement batteries may be needed.

Consult your Owner's Manual for illustrations and additional instructions. If these steps don't resolve the issue, I recommend contacting Hoveround Technical Support at 1-800-96-HOVER (1-800-964-6837) for professional assistance

It could be charger issue or battery issue.
You can try this charger here: https://chargerbuy.com/products/charger-for-hoveround-mpv5-power-chair It's UL certified.

It is possible that the new batteries are bad. This happened to me once. The charger though is probably the culprit for your problems. Have the charger tested first, or ask a scooter or power wheelchair store test or charge your batteries.

Without the charger the batteries would go dead. You could put a voltmeter across the batteries and you should read more than 28 VDC while charging.

Ed After a year the batteries are shot and the charger cannot revive them Sorry but you're gonna have to spring for 2 new U1 batteries. Hope this helps you

Normally the power chairs will not operate when connected to the charger. If you mean the controller comes on when connected to the charger but it wont come on when the charger is disconnected, I would test the batteries first, then the connections and fuses. Did a technician inspect your power chair to determine a controller was needed, or was that just a guess by the representative over the phone? If your insurance will not cover the repairs, I would recommend spending $50 for a technician from Hoveround to come out and inspect the chair to determine what is needed to fix it so you know for SURE. It may be something simple and inexpensive.
Good luck!

Firstly, it is bad news to use an extension cord with the charger as it can get very hot. It will sometimes take 8-12 hours to get a full charge on the batteries. If the light does not go to green on the charger, the batteries may be damaged and not able to take a charge. This is especially true if the Power chair was stored after your father in law died; the gel in the batteries may have gone solid. The lights on the controller will go left to right then back if the charger is connected properly.
The brake release knobs both need to be in the UP/DRIVE position for the motors to engage.

If your Power Wheel Chair has been sitting idle for a while, the batts may need to be completely replaced. There is a gel inside the batts that need to have a current run through them via the charger on a regualr basis otherwise it will solidify. If the charger lights are onm you have connected the charger correctly for over 24 hours and the batteries are still not showing they have been charge, there may be damaged cells which means both batteries need to be totally replaced.

check current output of charger to see if it makes info on back mostlikely charger went bad

The battery charging connector, which may appear as the female connector of a stage-quality microphone, is underneith the Joystick control arm. An external charger should have been provided by the seller, so if you don;t have one, you'llhave to contact the chir manufacturer.