"Unsupported Device"

Hi

so, I am driving home last night, charging my I-Phone 4 via a Belkin I-Phone charger in my car, as I have every 2-3 days in the last month without a problem, when all of a sudden, at 63% charged, I get a bit YELLOW triangle on my i-Phone with the label "This is a non-supported rechargeable device". This flashed for a few times then my screen went black.

Unplugged, hit the Home key, swiped, ad back to my home screen.

Plugged in the charger again, went to 68% charged, and then, bingo with the Yellow triangle etc etc etc....

Huh?

Any thoughts on what may be causing this suddenly?

Kind regards
Rod
Perth