Apr
Let’s get off on the right foot by asking a simple question:
What was wrong with the existing spring design?
The quick answer is, simply put, “nothing”. Or, better, the answer really depends on your individual criteria. To answer the question thoroughly, we’ll need to see what a hot-spring actually does, and how. Appearances can be deceptive.
Apart from the obvious, which is to provide a flexible contact interface between a battery and a fixed contact point, a collapsible spring must be used to provide the absolute minimum level of protection when a primary means of short-circuit protection is not available. When heated, a collapsible spring is not able to maintain its shape. Oddly, this is a desirable property, because, under short-circuit conditions, any battery will quickly get hot. As soon as that happens, the spring will absorb some of its heat, slowly losing its flex. This, in turn, will interrupt the circuit, preventing the worst. Heat produced by the resistance on either end of the spring can also have the same effect when the current is high.
Depending on its shape, length and wire diameter, a spring will respond differently to thermal stress. The same parameters also affect its electrical performance – as an example, when heated, a thin, long spring with many turns will lose its flex/shape much faster compared to a thick, inflexible spring with a similar total length, assuming that they are both the same material. However, the latter one will always perform better as an electrical contact!
So far, the springs used in the Roller and Dingo were designed with safety in mind – they are made to lose their shape reasonably fast and soften when heated, effectively performing sub-par under borderline heat/current conditions. Put simply, if your battery got hot when stressed, the spring would also suffer with it. In practice, this poses a problem in cases where stressed batteries or IMR fakes are used in combination with very low atomizer resistance values. If your battery could handle that 0.8 Ohm resistance without warming up, the spring played along just fine, as long as it hadn’t previously softened up due to a short.
Which, again, opens up the same old topic: When vaping with resistances below 1.5 Ohms, one really needs to absolutely know that *everything* is up to the task – starting with the battery. Most batteries are not up to it, either because they are far past their point of retirement, or because they are not what their wrapping suggests. To go above 3 Amps, the atomizer must also be electrically capable and properly set up — off-shelf, unplated center post screws with sharp edges and badly attached wires simply won’t cut it. But let’s get back on topic.
When the time came for a new batch of springs, we weighted things, gathered tons of feedback and decided to make 2 changes:
- Change the spring shape in a way that balances the performance / safety a bit more in favour of performance.
- Provide precious-metal-plated springs as an option to reduce contact resistance.
The new springs for the Roller / Dingo have a thicker wire diameter, reduced wire length, fewer twists and an optimized shape, all of which contribute to minimizing voltage drops under all conditions.
Additionally, the new spring design is able to better tolerate thermal stresses, which means that some safety has been sacrificed in return for better performance.
This decision comes from the simple fact that springs cannot provide any dependable battery protection or user safety anyway, since they only react only after a battery has overheated. By that time, any battery will be partially damaged, exposing the user to serious risks. So, if you care about protecting your batteries and — most important — yourself, a hot-spring will *not* save the day, even if it’s a little soft.
With so many primary protection methods available (such as the Bug), there is no excuse if the aim is to minimize the risks involved — and since day 1, we have strongly advised against relying on hot-springs for safety.
One change that results from the new spring shape is that springs are now mounted below the bottom cap delrin spacer, which needs to be removed in order to install / uninstall the spring. The spring has been designed so that the bottom turn can be made to sit snug against the Bottom Cap ring threads – this has been done to minimize current flow through the Bottom Cap disk / ring threads and possibly improve performance a bit.
The second decision is also a performance-oriented one — pure brass springs oxidize rather fast and require periodic cleaning to keep working well. The new springs are manufactured in 3 different variations, each with its own pros and cons:
- Plain, unplated brass springs provide good performance, but their top/bottom contact areas must be routinely cleaned. This is the standard option with non-Custom units, and a good choice for the cost-aware vaper.
- Silver-plated, brass-core springs provide the best conductivity. However, pure silver has poor mechanical properties, which means that the plating will slowly wear off. To remedy this, silver-plated springs have an additional corrosion/stress resistant under-plating, which, however, is not as conductive as silver, but still better than un-plated brass. A good choice for the best possible performance and still better than un-plated brass even if the top layer wears off after many months of use.
- Rhodium-plated, brass-core springs provide great conductivity, but not as good as pure silver. However, Rhodium is an extra-durable plating material, which will not tarnish in any environment. Plus, it has a bright, grey-silver tone, that looks simply unreal. Its only real downside is, of course, its price.
So, to answer the question we started with, the new un-plated brass spring will probably provide better performance in conditions which should be avoided anyway. The plated versions are certainly a further step up. For those that like to decide what suits them best by themselves, the two options should cover all bases, at prices that we’ve tried to keep as low as possible.
The other two options – going springless, or using a Bug – still remain, with the Bug providing both better performance than springs *and* unmatched safety.
livraison 36 heures après commande trop fort ,très beau mod facile a utiliser bravo
is this idea of a small circuit with the spring something worth looking at?
http://youtu.be/5pmKjA9IiHc
Thanks Manu for your informative response. I was looking a for some extra safety for your mech mods and I see you have the Bug coming out which I will get. Thanks again.
That’s a good idea, looks like a resettable fuse soldered on a small board with a collapsible spring.
In this case the spring is simply there to take up the space between the cap + battery and close the circuit. Since the fuse reacts before the spring gets warm, the spring will always keep its shape.
The problem is that adding many elements in series requires very careful soldering / assembly to ensure that all contacts are good for high loads.
Spring contacts in particular may become quite resistive due to contaminants or insufficient force and simply collapse on themselves due to heat.
Another issue with tiny springs is that using them with batteries that get hot during use will result in a gradual collapse and / or voltage drop due to insufficient contact force. On one hand, this is desirable because the battery gets hot, but on the other hand it can become very hard to diagnose issues related to partially collapsed springs.
The best practice when using a fuse is to have an adjustable component that closes the circuit without a spring, since resettable fuses are thermally activated, too. The adjustable cap of the Dingo is a good example.
Thank you sooo much for shipping my order so fast. Your product is by far the best quality available. I’ve wasted soo much money but finally came up with your company. I’ll refer you to everyone!
EYVA PROTI…..
I am a sub-ohm vaper (0.7 & 0.4Ω respectively). I would get these random “hot shocks” instant heating along my Roller, usually at the bottom cap, sometimes at the little lip on the inner tube and rarely, but surely along the outer tube. I thought it was shorts… Decided to try something other than an AW IMR battery and picked up a MNKE IMR 18650.
Just got the MNKE IMR 18650 today and shortly after popping in the freshly charged brand new MNKE IMR, bottom cap was heating up. AW IMR would only do it towards the last half of battery life. MNKE did it right off the charger.
Long story short, I posted on a forum asking if I had gotten a fake MNKE, it’s not a fake. But what a reply had said is exactly what caused the problem. I don’t know how I didn’t get this right off the bat!
It’s resistance within the mod. Now, I know the Roller is one of the lowest resistant mods out there, but this is exactly what it was… I remembered Chris’ post about modifying his spring, I decided ah why the heck not, since I have spares. So I ensued on the same modification and 10 minutes later, I had a cone shaped brass spring.
Popped it all back together and I haven’t had any issues with the bottom cap getting warm, at all.
However… I am getting slight warmth in the switch housing still, but that could just be the atomizer transferring heat.
So I second the notion that Chris’ notion that a cone shaped spring sandwiched between the delrin grommet and bottom cap disk has improved the performance…
Now whether I should cone shape the silver and rhodium springs is a question I can’t answer… Such precious metals, I don’t want to destroy.
Check the polarity of your battery. Positive pole goes in, negative goes on the spring.
You can start by cleaning all metal parts thoroughly with something suitable for SS. Then, tighten the bottom cap disk well with a hex key and get rid of the spring for a couple minutes, just to see if it makes a difference. A likely culprit is the spring, but it could be something totally unrelated to the bottom cap, or even the Roller.
If you feel adventurous you can also use the Roller like most mech mods — springless. If you know someone who has a RO60+ Roller with a new spring, you could also try his / her bottom cap on your Roller and see how it works, but springless will always perform better.
On a more personal note, I think that 10 A is a lot. Most mods and atomizers are pretty much unsuitable for such current levels. You need a lot of resources and training to design proper electrical interfaces at these current levels.
Regarding the tingling, it’s more likely to be related with ESD than anything else. You can’t ‘feel’ any shocking effects from a 4 V voltage source. The current is also irrelevant, since it’s only the potential difference that can cause current flow through your body. So it has to be ESD.
Anything you suggest for the Roller?
At 5.7 (0.7 Ohm) and 10 A (0.4 Ohm) DC, even the slightest bit of dirt that adds some contact resistance on any interface will heat up. At these current levels, *everything* becomes critical – and, most, important, an unplated, surface mounted spring won’t suffice to transfer power, unless it’s very very rigid. 150-200 grams of force on either sides (battery – cap) would never give you a low enough resistance to prevent heat buildup.
The old, unplated spring would give a voltage drop between 0.05 and 0.1 V at around 2-3 Amps, more if it was stressed / collapsed / oxidized. At 10 Amps, I wouldn’t be surprised if it started to produce perceivable heat.
The new springs are cone-shaped and built from thicker wire to increase the contact force – I think what Chris said is that he shaped an old spring to look like the new ones.
Still, 10 Amps on a handheld, battery-operated device is pushing quite it a bit. I wouldn’t feel easy about it, not without a thermally-activated fuse and an over-current fuse tripping @~12-13 Amps, because, well, 10 Amps is already a very serious load, even for 18650 batteries.
Theoretically speaking, at 10 Amps, you should replace the spring with a custom fuse, get rid of all threads you can and vape with something with fewer in-between contacts.
Yeah it never had bad performance. It could be psychological but it seemed like less lag between the time I pressed the button and the when the coil on my rebuild-able atomizer produced full vapor production. Nevertheless, I love the new spring options. Thanks for continuing to update this product!
I look forward to seeing a rebuild-able atomizer designed for the Roller/Dingo!
This is interesting. I took one of the Nickel plated springs and formed it to the same design as you have shown here and removed the delrin spacer (which I in turn lost). Since I did that I have noticeably better performance. I have not had even the slightest issue in regards to safety or the battery getting hot either.
Hmmm, perhaps because you did something like this:
“The spring has been designed so that the bottom turn can be made to sit snug against the Bottom Cap ring threads – this has been done to minimize current flow through the Bottom Cap disk / ring threads and possibly improve performance a bit.”
Thanks for your input, Chris! Definitely confirms our own findings, but it’s surprising that you could actually notice the difference.