bannaruj

Normally I drive slow , but today I just test my engine by push full throttle of pedal. Its accelerate is ok but after 100 km/h passing the battery warning charge lamp (the red right side of panel) is appear. When I lower to 60 km/h for a while , its disappear.
I check my battery, it was changed since 6 month ago, my dynamo still in good condition. I am so curious.
What is it might come from what cause? the main belt is slip so the dynamo won't work properly?