You're hardly the only one facing this issue; I posted this on the other thread, but I'll post my "fix" here as well:
Ran into this exact same issue recently. Thought it might have been the battery's issue or the cable's issue, but it turned out to be the charging port. Didn't want to get a replacement Triumph, as mine worked flawlessly besides the bad charging port, so I ordered this from Amazon:
Amazon.com: Hyperion Motorola Triumph 2 x 1600mAh Battery + Charger (Compatible with Motorola Triumph Motorola Triumph WX435): Cell Phones & Accessories
Now I have 3 batteries total which I charge through the external charger provided and swap them in and out as needed. I even prefer this to my old system of putting my phone on the charger as soon as I get home, as now I never have to wait for my phone to charge. I found this to be a great workaround to the faulty charging port on the Triumph.