How old is your DS battery? If it went through multiple charges like, a lot, it's most likely the battery itself. I think these batteries only have a charge limit of around 1000 times? I could be wrong. But that's being generous. The more charges you give the battery, ironically, the shorter it will last.
wrong, lithium ion batteries can be charged quite often, it is bad to charge a ds battery when it is low in juice.
QUOTEA lithium-ion battery provides 300-500 discharge/charge cycles. The battery prefers a partial rather than a full discharge. Frequent full discharges should be avoided when possible. Instead, charge the battery more often or use a larger battery. There is no concern of memory when applying unscheduled charges.