GRB 150818***A***, Swift-BAT refined analysis S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 150818***A*** (trigger #652603) (NAME, et al., GCN Circ. xxxx). The BAT ground-calculated position is RA, Dec = 230.341, 68.343 deg which is RA(J2000) = 15h 21m 21.8s Dec(J2000) = +68d 20' 34.8" with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 36%. [Description about the mask-weighted light curve] T90 (15-350 keV) is 143.1 +- 21.8 sec (estimated error including systematics). The time-averaged spectrum from T-25.3 to T+176.0 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.87 +- 0.09. The fluence in the 15-150 keV band is 4.3 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+1.57 sec in the 15-150 keV band is 2.4 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/652603/BA/