The testing light continues to blink when I plug in a battery. The batteries appear to still work but they don't charge or the charger won't charge them. I'm not sure what's wrong.

A blinking green light on a Segway Ninebot charger typically indicates that the charger is properly connected and charging the device, but the battery is not yet fully charged. Once the battery is fully charged, the light should turn solid green. If the light continues to blink green and the battery does not charge, it could be an issue with the charger or the battery. Try using a different charger or testing the charger on another device to see if it is working properly. If the issue persists, contact Segway Ninebot customer service for further assistance.

Question moved to a Ryobi category from MISC.

If they both show charged, they are unlikely to be incorrect. You can test the contacts of the batteries with a test meter, and you can also test the charger output.

If they don't work in a tool, the tool may have failed. Having said that, they do appear to have some history of this. Check out the videos.

https://www.google.com/search?q=Ryobi+18+volt+charger+shows+fully+charged

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please see the commentary. God bless you

• 
  The majority of laptops will display a solid green, blue or purple battery light to indicate that the battery is fully charged. Most manufacturers indicate that a laptop is in the process of charging by displaying a solid or blinking green, orange, blue or purple light. If your battery indicator light is green, blue or purple, the battery is probably functional, regardless of whether the light is blinking. If the light is solid orange, the laptop is probably in the process of charging.
  
  

Battery Error Coneventions

• 
  Many battery manufacturers use rapidly blinking lights to indicate that a battery's charge level is low. In general, a laptop will rapidly blink orange or red when its charge drops below a certain level until the computer is plugged into a power outlet and charged. If your laptop's battery indicator continues to blink rapidly in orange or red or if it remains red even when it is plugged into the charger, it indicates a problem with your battery or the charger.
  
  

Read more: http://www.ehow.com/info_12183593_blinking-battery-light-laptop-mean-charger-not-charging.html#ixzz2fu5qhEWg

If possible test with another charger like a car charger if you have one
also try removing the battery plug in the charger and put the battery back in (don't touch the contacts/gold pins)


if it works with other chargers then the charger is bad


if it doesn't work with other chargers charging port/battery/phone is bad

Batteries don't always look degraded but if they've been in use for a while or have a bad cell, they will show up bad on the charger and it won't charge them. The only way to test the batteries is to try to charge them on another charger. If the batteries show defective on another charger, they are bad and you'll have to replace them. Also try to charge some batteries you know to be good on your charger to see if it's the problem. If your batteries charge on another charger, your current charger is bad and they don't have any replaceable parts in them so you'd be looking at replacing it.

Not only do the batteries go bad, but the chargers as well. If you can, plug in the charger, don't connect the battery to it and test the voltage output with a volt/ohm meter. This should let you know if indeed, the charger is bad. Chargers get hot and don't last forever.

If working should turn on with adapter plugged in, maybe the internal jack is broken, move adapter plug around slightly and see if it moves at all, should not. Does any lights com on or do you hear the fan ?

Sound like the batteries are on their last leg. Have them load tested.

I had this problem a few weeks ago (i.e. flashing red LED). All I did was remove the power plug from the charging unit, turned it around 180 degrees, then plugged it back into the charging unit. Red LED came on steady & the battery (which is the one that came with the camera) recharged as normal.