Help me with my battery situation

[LPnTX]

I have an 07 Drive with the XCT300 controller and Bandit Plum Quick upgrade to the stock Hitachi motor. The batteries are 4, 12V Trojan 1275 installed in Dec. 2015. This cart is used about 18 holes of golf and a few booze cruises around the hood every week. It always had plenty of power and could easily go 27 to 36 holes a day. Now, I can barely get 12 or 13 holes and it gets very week. here are my battery readings

Full Charge
Pack 54.1
Batt 1 13.4
Batt 2 14
Batt 3 14
Batt 4 13.7

After 10 hours sitting and no use
Pack 53.7
Batt1 13.4
Batt 2 13.6
Batt 3 13.5
Batt 4 13.7

Under load at full speed
Batt 1 12.5
Batt 2 12.5
Batt 3 12.3
Batt 4 12.5

Cart is slowing down quick and meter stars to flash yellow and red
under load 41.6
sitting still 47.8
Batt 1 12.9
Batt 2 11.9
Batt 3 12.4
Batt 4 12.5

do you think the batteries are just getting weak or do you see any battery that looks like it may be the weak link?

[cgtech]

#2 is clearly the weakest.