550EX recharge ?

[Canon10Digital]

Ok, i have the 550EX flash, and my question is, when the light goes on, is the flash always going to give me full power to the flash, even on low batteries. Meaning, do the batteries only charge the flash to full, then sit until it needs to be charge again? or do they play in part in how powerful the flash will be? and part two to this question would be, if the flash is on, and ready and charged, but i dont use it for say 10minutes? am i wasting batteries? i guess its not a part two, more of an example of what im asking.......

[robertwgross]

Theoretically, if the Red ready lamp is on, then the flash is ready to go full blast. I have a belief that I can't prove that you may not always get full blast power until a second or three afterward, depending on the state of the batteries. In other words, if your batteries have been halfway run down, I think maybe the ready lamp is on before full power is present. Or, maybe that's just my unit.

Once the ready lamp is on, the batteries don't drain too much to keep the ready lamp on. However, it still takes a little bit. You can kind of tell by the amount of "whine" noise how much power it is consuming. When the noise is fully audible, it is sucking the most power. When it is just barely making a little noise, it is just barely using the batteries.

Once the main flash unit capacitor is charged up, then it should be able to do whatever it has to do correctly.

The manual says that there is a yellow half-ready lamp to show when it is ready for quick flash only. I have never ever seen that.

---Bob Gross---