The voltage on the tip of the glow ignitor is 12v-14.4v i measured it with the voltage meter so in order to keep it from burning up i suppose they use some kind of low current supply.
You are right about the glow though...it does draw as much current as it needs...the only case my "case" would stand is when the draw is very high and the smaller battery can't keep up with it which is not the case here.
I guess the plug draws anywhere from 5-10A/h, so there shouldn't be any difference.
My mistake here!!!