If your able to go 2 days on a 125AH battery then you are using 60 to 80 AH over that 2 days or call it 40AHs/day. A decent sunny day the 150 watt panel should be able to do that and then some. I'm a mornstar controller fan so would recommend a morningstar sunsaver 10 amp controller (no need to derate these controllers, overloads are designed in) but several reputable people on here (HiTech and BFL plus others) are very successful with the less expensive landstar controlers. With the landstar you do need to derate so get the 20 amp model.