I'm sorry to hear that you are seeing a flashing red light on your Duracell Ion Speed 4000 charger. This means that there is a problem, and the batteries are not charging.
There are a few reasons this could be happening, such as the batteries being too hot, or positioned incorrectly. If the batteries are too old and need to be replaced or if they are not NiMH batteries, this can happen as well.
Please give us a call at 1-800-551-2355 so we can be of further assistance with this. You can reach us Monday through Friday from 9am-6pm EST.
Hope to hear from you soon,