The amber flashing light simply means the battery is fully charged.
This usually happens with a replacement battery not manufactured by Dell.
Not a big deal.
If you open your power meter (right click on the icon) and notice the charge continues to diminish even while plugged in and indicating "charging"
You should unplug and use your laptop until the battery is depleted.
You can set adjust the power properties (right click on the same icon) to hibernate when the critical battery reaches 5% so that you don't lose any work in progress.
If the battery will not begin to recharge after running it down and plugging back in, leave your laptop plugged in, remove the battery and lock it back in place.
The computer will reset and the battery begins to recharge again.
This appears to be a feature that occurs in replacement batteries to ensure the battery is kept at an optimal charging capacity.