Ebay product descriptions aren't worth the pixels they're printed on.
If those LEDs are actually drawing the power they claim, the output would be more like 3000 lumens instead of the 800-900 listed.
The listed 940 mA input power calculates to 12.22W at 13V.
For that price, I'll believe the lower numbers and dismiss the higher ones as false advertising. Actually, I don't even believe the lower numbers and expect it'll be half as bright as they claim.