This letter considers simultaneous wireless information and power transfer in ad hoc networks, where each transmitter (TX) is wirelessly powered by power beacons (PBs) and uses the aggregate received power from PBs to transmit to its desired receiver (RX). Using stochastic geometry, we formulate the total outage probability at a typical RX in terms of the power and channel outage probability. The former incorporates a power receiver activation threshold at TX while the latter incorporates maximum transmit power at TX and interference at RX. For the special case of path-loss exponent of 4, we derive accurate expressions for the power, channel and total outage probability and study the effect of the system parameters on the outage performance.