Yes, the short battery cap is not the best choice for 2x18350 because it leaves tube threads exposed causing tube wobble. I have purchased all of my Sigeleis from US vendors and have no experience with fasttech. My two Sigelei Zmax V3s and V5 were ordered from three different shops. The first V3 was shipped with the tall battery cap only while the second generation V3 and V5 shipped with both caps.My V5 arrived. Flat top. The actual flat top with the air slots.
It only came with one bottom cap, the small one. So if I stack there are threads exposed on the tube. Also the spring would be nearly fully compressed. Which I understand applies too much pressure on the B+ connector and therefore the board/bracket.
Has anyone else only had the small cap dilivered with a ZMAX V5 or is my difficient?
The 10mm cap is best used with single 18350 batteries only. This gives the Sigelei V3 and V5 it's shortest length of 100mm, the same as Sigelei Zmax Mini. Depending on spring length the tall cap may or may not have weak spring contact when used with a single 18350. The best choice for 18490, 18500, 18650 and 2x18350 is the longer 15mm cap as the 15mm cap is easier tho thread onto the tube than the short cap. With the battery tube length properly adjusted V3 and V5 tube lengths with batteries longer than 18350 are the same with either cap.
I have seen some posts on this thread from other users who received only the short cap but can't recall which vendors they purchased from.
It seems that some distributors or vendors do not ship V3 and V5 with both battery caps while others do. We also see variations in top caps, button materials and logo placement from vendor to vendor. It seems as if Sigelei will customize these features for anyone who places a large factory order with them.
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