Electric Charge, Beacons and You

Beacons need electric charge (hereafter, EC) to function properly. There are two major ways they bleed off power - the constant drain of having the beacon running, and the huge spike in power required to initiate the Karborundum reaction that makes the beacon do what it does. Both of these are heavily influenced by three factors:

1. The amount of Karborundum on your beacon vessel. More Karborundum requires more power to initiate the reaction.
2. The gravitational field at your current location relative to your beacon's gravitational tolerance. The farther down in a gravity well you are, the more power your beacon needs to remain online.
3. Whether or not the beacon has a Gravitational Mitigator online. The GMU allows beacons to operate deeper in gravity wells than they normally would be able to, but significantly increases their power usage.

You may find that a beacon deep in a gravity well with a significant fuel load has a VERY HIGH startup cost. The initial onlining charge can easily consume tens of thousands of EC if you plan poorly. Therefore, it's advisable to turn on the beacon in a high orbit with minimal fuel and the GMU turned off. After the reaction is started, you can add more fuel, turn on the GMU and move it to a closer orbit. Your continuous cost for operating the beacon will still rise with those factors, but you'll avoid the need for massive battery banks. Of course, you may want those anyway - Kerbal engineering should always plan for the contingencies.