I did both of Reg Sniff's suggested mods to my 2013 model TDI SL. I also use a 16v battery pack. I was testing it yesterday on pieces of nickel. I buried a 1 gram piece at 6", and a 1.84 gram piece at 10". The TDI saw both with the 7.5"DF coil, and the 8 x6 NF Sadie coil. The 12"DF coil could only see the 1 grammer....same for the Super Pulse 14" 350. The signal on the 1.84 grammer was faint, but repeatable. I'd definitely have dug it in the field. The signal on the 1 grammer was strong with bot