The operating instructions say that after 16 hours the red power/charge indicator light would go out, indicating the batteries are fully charged. After 3 days the red light on my unit is still on. The green light comes on when you remove the headphones from the cradle and the headphones work, but the red light comes back on and stays on when in the cradle. Is this ok, or does this mean the batteries are weak and can never fully charge?

the trimmers switch may be faulty.

CHARGING THE BATTERY PACK
Battery packs for this tool are shipped in a low charge condition
to prevent possible problems. Therefore, you should
charge them until the green LED on the front of the charger
comes on.
NOTE: Batteries will not reach full charge the first time they
are charged. Allow several cycles (operation followed by
recharging) for them to become fully charged.
CHARGING A COOL BATTERY PACK
See Figure 3.
If battery pack is within normal temperature range, the red
LED on charger will come on.
NOTE: If the charger does not charge the battery pack
under normal circumstances, return both the battery pack and
charger to your nearest Ryobi Authorized Service Center for
electrical check.
n Charge the battery pack only with the charger provided.
n Make sure the power supply is normal household
voltage, 120 volts, 60 Hz, AC only.
n Connect the charger to the power supply.
n Place the battery pack in the charger aligning raised rib
on the battery pack with the groove in the charger.
n Press down on the battery pack to be sure contacts on
the battery pack engage properly with contacts in the
charger.
n Normally the red LED on charger will come on. This
indicates the charger is in fast charging mode.
n Red LED should remain on for approximately 1 hour
then the green LED will come on. Green LED on
indicates battery pack is fully charged and charger is
in maintenance charge mode.
NOTE: The green LED will remain on until the
battery pack is removed from the charger or charger is
disconnected from the power supply.
n If both yellow and green LEDs come on, this indicates
a deeply discharged or defective battery pack.
Allow the battery pack to remain in the charger for 15
to 30 minutes. When the battery pack reaches normal
voltage range, the red LED should come on. If the
red LED does not come on after 30 minutes, this may
indicate a defective battery pack and should be
replaced.
n After normal usage, a minimum of 1 hour of charging time
is required to fully recharge battery pack.
n The battery pack will become slightly warm to the
touch while charging. This is normal and does not
indicate a problem.
n Do not place the charger and battery pack in an area of
extreme heat or cold. They will work best at normal room
temperature.
NOTE: The charger and battery pack should be placed
in a location where the temperature is more than 50°F
but less than 100°F.
n When batteries become fully charged, unplug the
charger from power supply and remove the battery
pack.
Source(s):http://toolboyworld.com/eBay/Ryobi_P110/...

Completely wrong. Quoting from the user's manual:

"The charge indicator light (LED), located on the charg- ing stand, will light up red and glow when the char- ger is properly connected to power supply. This light indicates the charger is operating properly. It will remain on until battery pack is removed from charging stand or charger is disconnected from power supply.

After normal usage, 3 hours or less of charging time is required to fully recharge battery pack.

If both red and orange LED indicators glow, the battery pack is deeply or completely discharged, and 6 hours or longer of charging time is required to fully recharge battery pack.

Note: If charger does not charge battery pack or orange LED continues to glow after more than 30 minutes of charging, return battery pack and charging assembly to your nearest Ryobi Authorized Service Center for electrical check."

So to summarize: red = charging. orange (yellow) = fully discharged battery. orange after 30 minutes - bad battery or bad charger.

Charger flashing red indicates the battery is still not full and is in the process of recharging.
Red light steady indicates your battery is fully charged and ready to operate with your Coolpix 5000.
When red light is off it indicates there is no battery inserted or the charger is not pluged in.

I have the MDR-RF970R but I bet the battery is the same. If you have had the headphone for seceral years then I bet you are right, the battery is going. You might try using them till the battery dies and then recharge. This is called deep cycle and may time it will extend the life of rechargables.

If the headphones are new, then just check and make sure that they going all the way into the charge slot.

I will say it is not common for me to see the light off, but I use the headphones all the time.

Good luck.

The green light on the charger usually indicates that the batteries are fully charged and you are ready to go. Does the controller show the batteries are fully charged? Can you operate the power wheel chair for several hours? If so, you are good to go.
When you connect the charger, if the light goes to red to green within a few minutes and the battery power does not last more than 1-2 hours or less, it may indicate that that the batteries will not take a charge anymore and need to be replaced.

I don't know how to solve your problem but, the three lights mean this:
Red LED light indicates the battery is being charged
Green LED light indicates that the battery is fully charged
Amber LED light incidates that the battery power level is low - the battery needs recharge.
Do not recharge you battery over 24 hours.

Sometimes it takes longer than two hours. Leave it plugged in overnight if you can. The indicator light should go off after fully charging.

The lights are working, the batteries aren't. Red indicates power to the charger, and it should be on all the time. Green indicates a full charge, usually. If one or both of the batteries are totally dead, then the charger can't "see" them, and you will get a green light, but you will have dead batteries.

All power chairs use sealed, deep-cycle batteries. Deep cycle batteries, are designed for slow amperage dischare over a long time period, unlike a car battery that throws out a lot of amperage for turning the motor over. That's called "cold-cranking amps", and you can load-test a car battery to see if it will throw out a ton of amps for long enough to start a car. There is NO load tester made, or possible for a deep-cycle battery. A load test requires a 24-hour time period, and a complicated formula.

So, your course is to get some fresh, gel-sealed-batteries. You will need type U-1. Specify, gel-sealed-batteries when you go to the battery shop. A fresh set should get the chair up to about 12-16 mile range, which would be about 3-4 hours running constantly at high speed. Good luck.

From the manual:

"Attach the barrel tip of the AC Charging Adapter to the AC Charging port of the POWER TO GO® and plug the standard two-prong plug into an appropriate, functioning 120 volt AC outlet. The red Battery Status LED indicator will flash, indicating a proper connection has been made and the unit is charging. The green Battery Status LED indicators will gradually light as the charge level rises. The POWER TO GO® must be charged for approximately 11-17 hours prior to first use. All Battery Status LED indicators will be lit solid (the red indicator will stop flashing) when the unit is fully charged.

The indicator light turns red when the battery is
charging. It may take up to 1 minute for the
indicator light to turn on. When the headset's
battery is fully charged (about 2 hours), the
indicator light turns off.