Dimitri Clone questions, related to parallel vrs single

[Mrez]

So, my Dimitri clone arrived today. Took it apart to get a feel for how it's put together, and once satisfied, I put a pair of HG2s (20 amp) in it. I put my velocity with .19ish fused coils in it. I have been firing this particular atty and build on a single tube mech all day (VCT4s), it gets warm but nothing crazy. On the Dimitri the coils cook and the atty gets pretty hot.

If my understanding of battery operations is correct in parallel vrs single, then what is happening is that I'm getting less volt drop between the two batteries compared to the single batter in a tube mod, so more volts to the atty. Is that about right?

I also noticed the button getting a little warm. Not uncomfortably so, but noticeable.

The button is a bit finicky on this thing, needs to be adjusted just right to get the right throw with good contact. I think the copper strip might be a restriction point if everything isnt screwed down right. I've set it aside for now to muck about with tomorrow.

 

[Nikea Tiber]

Yeah, you get less volt drop off of a parallel mod vs a single cell mod; doubling the batteries halves the net internal resistance of the batteries.
The resistance drop is measurable in maybe tenths of an ohm, and more likely hundredths. The effect isn't huge, but you will get a little more wattage off of a parallel; the effect is more noticeable with extremely low resistance atties.

 

[mhertz]

Oh, I thought it was more... When firing e.g. a 0.18 build, then the 4.2v cell in a tube mech goes under load down to about 3.8v thereabout. The voltage drop of the mod is not that big, but I thought the majority of this drop was battery sag because of the internal resistance of batteries, like you stated, but when the resistance is halved and so the sag is halved, then that should be pretty noticable, on e.g. the OPs build, no?

 

[Mrez]

Ill be playing with it more tomorrow, but assume the button hit well...it was definitely a stronger hit.

 

[mhertz]

Btw, although it was on a tube mod, then I read that spring-loaded switches needs stretching often for low sub-ohm builds, as else they hinder the spring-loaded elements current-flow even when just slightly collapsing/loosing tension, and it seemed to have fixed my hot-button issue on the smpl with a 0.17 build, so maybe give that a try?

 

[Mrez]

Btw, although it was on a tube mod, then I read that spring-loaded switches needs stretching often for low sub-ohm builds, as else they hinder the spring-loaded elements current-flow even when just slightly collapsing/loosing tension, and it seemed to have fixed my hot-button issue on the smpl with a 0.17 build, so maybe give that a try?

I will do so on both my Dimitri and SMPL. I've set the SMPL aside in favor of my Stingray because I had been getting routine hot buttons on .2 - .25 ohm builds. With the Dimitri, I feel like the issue is less the spring, and more the travel distance, and the looseness of poistive pin and how it connects with the copper strip.

 

[Mrez]

Btw, although it was on a tube mod, then I read that spring-loaded switches needs stretching often for low sub-ohm builds, as else they hinder the spring-loaded elements current-flow even when just slightly collapsing/loosing tension, and it seemed to have fixed my hot-button issue on the smpl with a 0.17 build, so maybe give that a try?

Think I resolved the button issue. Found a small little spacer, so I slipped it between the copper strip and button base. Was able to tighten up the button a bit so the throw is better, but the pin remains snug. Hitting hard now, and no hot button. Maybe the loose fit was redirecting the current through the button inefficiently, causing the warm up.