# Rotating evod coils problem.



## blujeenz (24/12/15)

I needed to rewick my rebuilt evod coil and noticed that the kanthal coil had rotated inside the housing, choking the cotton due to coil twisting, which also caused some amount of gurgling.

Upon some pondering I decided there were 3 aspects contributing to this twisting coil issue.

the pos coil contact has thin ridges on each side of the air hole which dig into the batt pos contact.
the housing rim did not have the notches for the neg coil leg.
Screwing the atty down hard onto the battery in a fully seated position will make the problem worse.
I noticed that it was an older coil housing without the notches in the rim for the neg coil leg, thus allowing the kanthal to side much easier around the housing. 

Heres a view of the newer notched rim housing on the left. Probably a factory quick fix to stop the coil wire from sliding around the rim, the older version on the right which is the dual horizontal coil Kangertech evod/ mini Protank 3 style.






These very thin pos contact edges dig into the battery connection and grip. This is also a higher air flow 0.8 ohm coil contact.



Heres the chinese cheap copy with much more generous pos contact area, it is also the stock 2.1 ohm coils with a much smaller airhole. I havent had the rotating problem on this one yet.



Heres an Aspire BVC coil on a Titan pro tank for comparison, I doubt this coil will rotate due to the different contact design.



My paint illustration of choked cotton due to coil twist.


Solutions are:

cut a small notch in the rim with a thin junior hacksaw blade or needle file. to seat the wire leg

tighten the atomiser onto the battery until its snug, not bottomed out on the ego thread of the battery
make a note of where the pos center contact notches are and whether they line up with an outer airhole, or scribe a mark for reference, that way you can quickly acertain whether your coil is rotating with all the removals for juice and batt charging etc
a camera is a useful tool to record coil positions

Reactions: Informative 1


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