@Sumeeth
The default for not adding the end time is clearly stated in the rules as 72 hours.
6.2.5 Each domain and website auction must have the required information: domain, registrar, expiration date if rule 6.1.6 applies, starting bid, bid increments (default: $1), specific end date and time including the time zone or a relative end time (default: 72 hours after last bid), and payment options.
End Time - This must be clear with an hour, minute and time zone or X hours after last bid. (Default 72 hours after last bid)