When trying to charge my battery... the light flashes red. And the battery doesn't work when put in the camera. Is that a battery problem or charger problem?

If you don't use the battery for a long period of time even a new battery may become dead. You can try a new battery. If it still doesn't work then the problem is with the charging IC. u can also try a desktop charger instead of direct charger.

Hi, I'd suggest using a wall charger as they're able to provide more power to charge then a computers USB port. Often with camera's the USB port doesn't supply enough power so the camera doesn't charge at all.

Green light flashed, turned red, lens would not open. Put in new rechargeable batteries, still nothing. Someone here suggested to try regular AA cheapie batteries. IT WORKED!

new battery is required as it is too discharged to work after a year's time.

I found this while trying to solve my exact same problem.. It worked for me after about 7 times. Some other people on the site said it worked for them after 20 times. Good luck!

My NP 20 gave me the flashing red light of death and I got Casio to replace it. Then I had the same problem with my second NP 20 so I dug around for a way to fix it and I found the following advice on a site called FixYa. It worked instantly and I didn't risk ruining my battery.
ylu1 writes:
I had the same problem as this.
what i did was...
i kept putting the battery on the charger then took it off as soon as the red light came on.
i did this about 6 times.
doing this puts a bit of charge in the battery each time before the charger starts to flash.
after the battery as got enough charge in it it can start to charge.
hope this helps.

Take a nine volt battery and put + to + and - to - for ten seconds and try to charge again if it does not work then you need a new battery.

Here's what I found and it actually worked after about 7 times. Others said they had to do it about 20 times. Good luck!

My NP 20 gave me the flashing red light of death and I got Casio to replace it. Then I had the same problem with my second NP 20 so I dug around for a way to fix it and I found the following advice on a site called FixYa. It worked instantly and I didn't risk ruining my battery.
ylu1 writes:
I had the same problem as this.
what i did was...
i kept putting the battery on the charger then took it off as soon as the red light came on.
i did this about 6 times.
doing this puts a bit of charge in the battery each time before the charger starts to flash.
after the battery as got enough charge in it it can start to charge.
hope this helps.

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.

sounds like a dead battery. Plug the origional charger into it and the front led (below the flash) should flash red. If the red led in the back of the camera flashes or stays lit, then you have the wrong charger plugged in. (the camera won't power up if the back red/green led is on when plugged in)

What model of camera? You will probably need to purchase different battery.