I was an electrical engineer. It is not impossible to accomplish, but there are some tradeoffs that the prospective buyer should consider.
Moving the battery and a lot of the electronics to the coil, makes the coil a pretty expensive proposition. If your type of hunting demands multiple coil sizes, this can get very expensive.
Also, with all the electronics and battery in the coil, how small a coil can be built and have enough battery charge for a days outing? Is an 8" coil about it, compared to a 5" ?
Battery capacity (hunt times) versus coil weight (moment of inertia) versus torque on shoulder as detector is swept.
Rudy,
You make some good points.
According to Mr Andy Sabisch, Xp is releasing a smaller coil and new version for Deus (end of 2015 approx). New version is usable and will add some things even with the current available coils, but not all. And with the new coil---new version supposedly full --new version offerings.
How will this new coil stack up from a separation/depth standpoint to some other fine detectors with say 5 or 6" coils??? Who knows.
I'm hoping it is a competitor in this regard.
I also can say don't let the 11" coil size say fool a person when it comes to separation; especially in iron. Deus engineering/programming can make the coil act like a much smaller coil say 7"--WAG
And the 9" coil something in the neighborhood of 6"--WAG
It would be hard for me to put exact numbers to this---but it is absolutely breath taking to see either coil perform in iron for their size.
I've heard the new coil offered will be 6 x9".
Here's a good video, Deus wearing 11" coil I think, and going up against some other great detectors--some even wearing 7x11" coils.
And I don't think the video is rigged either--cause I've tested using some of the same and similar detectors (F75 is very near T2) and got the same results.
https://www.youtube.com/watch?v=qWenrozQ58o
Here's another video, with better narration than the one above.
https://www.youtube.com/watch?v=gGwqHyUSUI8
I'm no engineer, although many of my school teachers thought I should have pursued. This Deus--I can't really put my finger on it. But it seems somehow
its coil(s) doesn't saturate as easily as many other detectors when it comes to iron. I'm not sure its separation performance is based/depends solely on processor speed.