i had it tested under load it was all good when i took the standard pwr cable off and check it and put it on to try again it wasn't working so i thought it was the starter when i hooked up the jumper lead instant start the standard pwr cable had the eye terminal cut to the lead it was wrapped up so it wasn't obvious at first which kept throwing me off thinking the start was fked i just fixed up the standard cable new eye terminal and instant start no problems since
as for duty cycle charger i wouldn't have a clue but ive been using this battery for awhile with no issue no surging or anything