It's most likely that yours just needs replacing with a new one, but beware ultra-cheap generic copies: they're a lot cheaper, but often do not hold the stated charging capacity and usually the performance falls off far more quickly than the genuine Olympus article. If you're happy to carry a few spares and to replace them more often they can still be a sensible choice though as the genuine article is usually ridiculously overpriced. Avoid used Olympus batteries as you won't know whether they're any good until you've paid for them: worn out batteries look exactly the same as good ones, and good used ones can very rapidly progress to being worn out.
The other main possibility is that the charger has become faulty but unless abused chargers are usually highly reliable. If you know someone who uses the same battery in their camera you can check this by asking them to recharge your battery; you'll also find that some of the ultra-cheap compatible batteries often come with a charger as well, but don't expect it to charge as quickly as your Olympus model.
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Rechargeable batteries don't last forever.
It's most likely that yours just needs replacing with a new one, but beware ultra-cheap generic copies: they're a lot cheaper, but often do not hold the stated charging capacity and usually the performance falls off far more quickly than the genuine Olympus article. If you're happy to carry a few spares and to replace them more often they can still be a sensible choice though as the genuine article is usually ridiculously overpriced. Avoid used Olympus batteries as you won't know whether they're any good until you've paid for them: worn out batteries look exactly the same as good ones, and good used ones can very rapidly progress to being worn out.
The other main possibility is that the charger has become faulty but unless abused chargers are usually highly reliable. If you know someone who uses the same battery in their camera you can check this by asking them to recharge your battery; you'll also find that some of the ultra-cheap compatible batteries often come with a charger as well, but don't expect it to charge as quickly as your Olympus model.