BalancePowerTracker is an addon designed to provide a highly configurable bar to track Lunar/Solar energy, Eclipse direction and Eclipse buff.
It also can fire wanrnings when you gain Eclipse and provides energy prediction.
It's focused on using the CPU strictly necessary and no more.

PREDICTED ENERGY: Predicted energy analizes your current cast and adds its energy to your current energy, so BPT predicts where your energy is going to be after you finish your cast, and if you are going to proc Eclipse or not.
You can configure the indicators (bar,text,icons,arrow) of the mod to either display predicted or real info.
Also, you can configure the alerts to fire when you are going to get an Eclipse.
(Author's note: I feel Predicted Energy is the heart of BPT, I think without this option I wouldn't have made this addon, also it has taken up most of the time invested in the addon, however, I understand people value the choice to turn this off. At least, give it a try!)

Provides LibSharedMedia, Masque & MikSBT support:

• LibSharedMedia: Bar textures, alert sounds, fonts
  
• Masque: Eclipse icons skin
  
• MikSBT: Fire alerts through MikSBT
  

FAQ:

Can I disable it out of combat? You can't disable it out of combat, but you can turn the Alpha Out Of Combar to 0, so it won't bother you (CPU load out of combat is pretty much 0).

The energy seems a little erratic...? Predicted energy & eclipse are enabled by default, with this enabled, the mod will add the energy of you current cast to the bar, if you only want to change the size & position of the energy bar, I suggest you to uncheck this option.

Is there any way to have the awesome Blizzard art? Enable default art module, you'll get a bar like Blizzard's with some options (not nearly as many as with the Eclipse bar module).

Green bar: BPT is unable to access the bar/border texture, check if you have uninstalled it.

Pipe ...? In case you want some addon to fetch BPT predicted energy values instead of the real ones, you can try enabling this option. It will try to make ALL the addons and UI elements fetch predicted values.
This option has several drawbacks:

• You can't choose which addons and UI elements will fetch
  
• Increases BPT CPU (& reduces everyone else's) because all calls to UnitPower go through BPT
  
• Can cause taint issues (Pipe will disable itself when this happens)
  
  So I think you should leave this option unchecked unless you really need it

Castbar mode ...? With the changes to when energy is gained, you can see the spark in the cast bar as "how many energy of that spell I currently have", so with this option enabled (you should have the spark also enabled), when casting a spell that gives energy, the Eclipse bar will turn in a sort of castbar, still showing the arrow and the energy text. Just have this in mind: this isn't a castbar mod, so it shouldn't replace it, but this option reduces the places you need to have your eyes on.

ADDON AUTHORS:

LibBalancePowerTracker In v1.1.0 the energy track and predict features were moved into a library called LibBalancePowerTracker. This library is standalone and will avoid loading itself more than once. The API is commented in the first lines of LibBalancePowerTracker-1.1.lua.