Oops, after reading another post on using starter batteries for high demand / short duration loads like a coffee maker or microwave, I remembered why I bought two Battle Born 100aH batteries. The wife's hairdryer draws ~ 140 amps on high. Can't draw that much power from one battery - Battle Born lithium batteries are rated c=1, meaning that you can continually draw the amp hour rating of the battery, in this case, 100 amps. So I needed two batteries to draw 140 amps. Keurig draws ~80 amps, so that would have been OK on one battery.
