I have an HP8402B battery charger. Its plugged in but no red or yellow light and no fan. The plug is getting power. Can you help.

SOURCE: batteries aren't charging up. Chair want go.(Golden Compass)

That`s most likely your problem. When left uncharged for that long of a period,the batteries will discharge below 12 voltDC. The charger only recognizes 12 volts and up. So the charger can`t bring your batteries back up over 12 volts.  You will need to get them on a slow charger,like a car charger or have them replaced. If you know someone or have a voltmeter,set it on DC and check each battery.  If it is below 12 VDC,they need to be put on a slow charger or replaced.   

SOURCE: new batteries does not seem to fully charge.

The measurements below are for a 12 volt charger or across one battery at a time. In a 24 volt charger or across both batteries at once, double the values.
The charger will not show any output unless connected to a battery. To test the charger, attach the charger to the battery but do not plug in the charger. Connect a meter to the battery and read the voltage (9.8v - 11.6v).
Now plug in the charger. Read the battery again (13.6 - 14.2v).
The voltage must not be higher than 14.8 on the battery or the battery will over-charge - the charger needs service. If the voltage does not come up to 13.2v, the charger is not running. Again, the charger needs service.
Be patient. You can wait ten minutes and measure again. Batteries respond slowly to the charger.

SOURCE: The battery charger does not work. The red light

SEEK AN ELECTRICIAN WITH HIS METER WHEN SOMETHING GOES WRONG WE TEND TO THINK OF THE WORSE THINGS RATHER THAN THE BASICS,IM DISABLED MYSELF,THE BATTERIES ARE TO BE TREATED WITH RESPECT,I DONT KNOW WHAT CHARGER YOU ARE USING BUT PLEASE ONLY USE WHAT IS ADVISED BY MANUFACTURER,NOT ONLY THAT IF YOU DONT YOUR WARRANTY WILL NOT BE VALID.HAVE A NICE DAY COLIN.

SOURCE: CHAIR BEEN SITTING FOR A

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

SOURCE: How do I charge the Hoveround mpv 4? I plugged the

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.