I just got a Blackberry 7100t a few weeks ago on ebay and I charged it today because it was on 75% and it was sitting there for 3 hours and I finally went into status and it was still on 85%. So, I said I will give it another hour and it was still on 85%. For a second, I thought my battery finally gave up. But, I just plugged it into my computer via USB and it went up to 90% in 3 minutes. Is it my charger?