Resonators are powered by XM. Resonators start with a full charge, but the XM store is consumed at a rate of approximately 15% per day. Attacks on Resonators by XMPs also reduce their XM charge. Resonators will self-destruct when the XM charge reaches 0. If all Resonators deployed on a Portal go to zero, the Portal will revert to Neutral status.
Resonators can be Recharged using the RECHARGE Resonators action:
1. Choose the Portal when it is in “action range”
2. Touch RECHARGE resonator
Recharging Resonators consumes XM from your primary store. You can replenish your XM by walking around and collecting more XM.