The BC-VM10 battery charger, supplied with Sony cameras, uses the NP-FM series of rechargeable battery packs. The charger is a fairly simple device, but it may, at times, work poorly. The cause of the problem is usually minor and easy to fix.
Use only the "NP-FM" series battery packs that came with your camera with the BC-VM10 battery charger. Using other battery packs may damage the charger or battery pack. Extended use with the wrong type of battery may cause the charger to wear out.
Remove the battery pack from the charger if the "Charge" light flashes; this indicates the battery pack is incorrectly seated, or incompatible with the charger.
Clean the battery charger's contacts with a dry cloth to remove any dirt or grit that may have accumulated and may be interfering with battery charging.
Check if the charger's power cable is firmly connected to the charger and power outlet. Loose connections don't carry much, if any, power.
Check that the camera's battery pack is correctly seated on the charger. Press the battery pack onto the charging slot, then slide it into the slot. The "Charge" indicator light should turn on when the battery pack is correctly seated.