There are so many street vendor charcoal grills you can find in this humid and sweaty Bangkok city! I constantly see people are eating all the time.
In Silom area just in front of the convenient store, this fat guy has been around for long time and some people even invited him to their home to host a barbecue at their home.
You can order as many as you like and go with a little bag of rice, Thai sauce to go with it. That will send you to the heaven!!! By far this the best one I never had and its simple and inexpensive to have.