External 18650 Battery Pack and Adapter for the GrassHopper

[OF]

10-12 amps peak ( by math) . I will put a amp meter on it tonight to see actual and average amps...


It would need something that can drop the volts down from 12v to 4.2v while keeping up the amps?

I am having some doubts about this project..

I will focus on the aluminum adapter for now.

All you'll read is probably the average. Even 'peak capture' meters have to 'see' the highest point through a converter than only samples about 3 times a second. But average current is what makes heat happen anyway.

You usually need to experiment some with such schemes, but often a modest capacitor on the output can 'soak up' the spikes in current demand.

Good luck with it. But here reality beats theory every time.

OF

 

[Joel W.]

All you'll read is probably the average. Even 'peak capture' meters have to 'see' the highest point through a converter than only samples about 3 times a second. But average current is what makes heat happen anyway.

You usually need to experiment some with such schemes, but often a modest capacitor on the output can 'soak up' the spikes in current demand.

Good luck with it. But here reality beats theory every time.

OF

Thanks Sir! My meter is nothing fancy. The pulse width modulation in the back end of the grasshopper that operates the heater , it may not like an amp meter in the loop?

I honestly do not understand how the grasshopper works very well. It requires an oscilloscope to check the rear end of the hopper, I hear?

Somehow this pwm may trick the battery into flowing more peak amps than the battery can output? Just a theory I have heard..

So many question.....

 

[OF]

I honestly do not understand how the grasshopper works very well. It requires an oscilloscope to check the rear end of the hopper, I hear?

Somehow this pwm may trick the battery into flowing more peak amps than the battery can output? Just a theory I have heard..

I gave up on following GH a while back (until they 'got their act together'....) but the idea is simple enough and common.

There are two common ways to provide variable power, proportional or duty cycle control. You car's Cruse Control is an example of the first, the engine power is controlled over a linear range to suit the needs (more power if the car goes too slow, cut back down the hill) Always 'part on'.

Duty cycle, OTOH, is like your home heater or vapes like Solo. Here it's full on or shut off (never partially on) and over time the average is what counts. If it draws 3 Amps half the time it's using 1.5 Amps on average. Cutting it back to 1/3 drops the current (and therefore power) to 1/3 of maximum. And so on. You can shift slowly (like the home heater) or fast (like a light dimmer which does this 120 times a second). As long as you're faster than the time constant of the system it all averages out.

Since heat build up (the enemy of wire) is slow relative to the rate average counts there. If, however, that wire is too long the total loss heating the wire can become high enough to lower the available voltage to the load (this is why you need fat extension cords for long runs, to limit the drop not protect the cord).

PWM is the subset of that where the unit shuts on and off at a fixed rate (that changes with demand changes) with the percentage of on time (as part of the total) setting the output. PPM, other hand, stays on for a standard time but varies the time until the next on cycle (like your home heater does).

https://en.wikipedia.org/wiki/Duty_cycle

Normally you'd size the heater so full on is enough power to get to temperature in a reasonable time (as is done is Solo and similar designs. Keeping the peak power demands as low as possible. Sales types, OTOH want fast times and sometimes override common sense and sound design. I would not be at all surprised if that was in full bloom at GH, given their past WILD claims most anything is possible?

The meter is simply a resistor you put in series and measure the voltage drop across caused by the current. By Ohm's Law. Since the typical 'basic meter' is 200mV full scale, this means the ten Amp (normal full scale) reading represents 100mV detected. .1 Volt divided by 10 Amps says that resistor is 1/100 of an Ohm? The leads are probably more. Looked at the other way, the meter loss causes the available voltage to drop an additional less than .1 Volt. Using a slightly more charged battery more than makes up for it?

Yes, to monitor the changes in the pulse widths you'll need a 'scope. You can get into that game cheap enough (well under $100) but you really need to know what you're looking for (and how to deal with it) before you hook one up.

OF

 

[Shit Snacks]

Ah this is great, would love it if it was a plug in vs battery pack type adapter... Some day?

 

[Joel W.]

I am looking for a good 110vac to 4.2vdc adapter/wallwart but I have not looked very hard. With the connector I am using now, it could be just unplugging the battery pack and then plugging it into the wall for a desktop connection.

My amp meter read 5.6 amps max at start up when cold. (Not saying it is accurate but it is repeatable on any heat level.). I will measure voltage drop next during max amp.

Looking at my quick connect plug wires, they are maybe 16g. So, if everyone feels 18/2 wire is acceptable, then I will try that on the next model.

Any ideas for a better quick connect male/female plug?

 

[Hippie Dickie]

Any ideas for a better quick connect male/female plug?

i like the Deans - fairly small, can handle 80+A - check with R/C hobby websites. about $3.50 for Male/Female pair. i see minimal wear after thousands of plug/unplug operations. you can see the male plug in the last two images in my signature.

 

[Joel W.]

i like the Deans - fairly small, can handle 80+A - check with R/C hobby websites. about $3.50 for Male/Female pair. i see minimal wear after thousands of plug/unplug operations. you can see the male plug in the last two images in my signature.

Those defiantly look heavy duty enough, thanks. I feel kind of silly now looking at the plug that I used.

I was focused on the 10a part and completely missed the 18g wire part on mine. It's the locking threaded nut that I like on this connector and it's also water tight.

 

[Hippie Dickie]

Deans also has very fine strand wire ... i use the 16g, 660 strand Ultra Wire.

Ultra Wire
12 Gauge silicone wire with 660 strands of pure copper pre-tinned for easy soldering and corrosion resistance. The highest grade of copper and pure silicone insulation provide maximum power and easy soldering.

Wet Noodle
The ultimate wire for full race applications. 12 Gauge silicone wire with an unbelievable 1660 strands, it is so flexible that it feels like a wet noodle! The highest grade of copper and pure silicone insulation provide maximum power and easy soldering.

they sell pigtails - with 4" wire attached - so that is half the work already done. all from hobby stores, unless you need custom - longer wire, for example.

 

[Hjalmark]

this thread here is gold ... what a fantastic design of the working "prototype" of that grasshopper dummy battery !

very very interesting Joel W. !

 

[Joel W.]

Well, I probably have 500-600 hits now on the 1st prototype, but I did not like the contact design.

My newest prototype I built last night uses a hollow Delrin rod to hold the contacts at a fixed length and this rod can move a little inside the aluminum adapter.

This eliminates the need for a front spring on the positive contact and it lets the factory spring in the back end do all the work, like it was designed.

If the length is set right, I get one full turn on the back end in spring load tension and that is about the same as a stock battery spring load tension. It works great, until I screw on my other hopper body.

My problem is both of my prototypes now only work on one hopper body and when the other hopper body is installed, I get a normal solid red light but then the blue light pulses at one quick pulse per second and then the unit shuts off after 10 sec. This is different from cop lights that I have seen.

If I install a battery back in that nonworking hopper body, it works just fine?

I don't believe it is a contact issue and I honestly do not understand yet what is going on because they both worked just fine on the pack when I first tested them out.

I will keep at it., I think it may be cord length related as the start up time on the working hopper is a few seconds longer with the pack vs a single battery.

 

[subway13029]

This is so interesting. And the hopper seems to be a marvel of technology as nobody( maybe even inventors) understand why it does the things that it does at times. I'm behind ya Joel you've done some amazing work.

 

[ZC]

https://www.amazon.com/gp/product/B00C9UUFHC/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

This voltage buck will drop your voltage down and keep up with the amps, it's what I'm using for my Milaana power adaptor and it works great.

 

[herbivore21]

Ah this is great, would love it if it was a plug in vs battery pack type adapter... Some day?

This! IMO I don't wanna be messing with even more batteries (I'm sure some will not mind of course), but a plug-in to wall socket design like this would be ideal and give the hopper back some life. I'm at home 99% of the time, I need that power on tap, I don't wanna charge batteries ever if I got a wall socket handy lol

Could we find a high-end switching 110/220 DC power supply for this one (to ensure global voltage compatibility - not just 110v!!! These supplies exist for laptops already and there is no need to limit the audience) Seems to me like this should be easier to build than the battery pack even?

My hopper gathers dust because I can never be bothered to charge batteries. A solid DC wall socket power supply would give it new life (actually make it ideal for my needs, I don't need long battery cycles for portable usage).

No problem at all if you can design one of these that requires to be used separately from the battery pack, separate products for these two applications seems reasonable enough!

Let me add that one or another switching 110/220v DC laptop power supply should deliver enough juice and be compatible with the voltage buck that ZC mentions above to keep the voltage down at the levels we need.

@Joel W. Holy shit bro btw can you make a threaded mouthpiece extender, given that you've been able to make one for this power mod? It would be such a major benefit to have a longer vapor path and less harsh vapor for direct draw use!!!!!!!!!

 

[Joel W.]

@Joel W. Holy shit bro btw can you make a threaded mouthpiece extender,

. Thanks man, I think I can(it's on the list). But really, once you stick this chunk of aluminum in there, it soaks all the heat right out of the hopper body and only the last one inch at the mouth piece gets warm during use, but i can pull several (5-6 hits) in a row before it gets uncomfortable, unlike the stock battery hopper(2-4 hits) combo.

 

[herbivore21]

. Thanks man, I think I can(it's on the list). But really, once you stick this chunk of aluminum in there, it soaks all the heat right out of the hopper body and only the last one inch at the mouth piece gets warm during use, but i can pull several (5-6 hits) in a row before it gets uncomfortable, unlike the stock battery hopper(2-4 hits) combo.

Sorry man I should clarify I'm talking about a longer mouthpiece to reduce harshness of vapor for direct draw hits, not hotness of the unit in the hand - which I never found to be unbearable

 

[Joel W.]

Sorry man I should clarify I'm talking about a longer mouthpiece to reduce harshness of vapor for direct draw hits, not hotness of the unit in the hand - which I never found to be unbearable

No problem man, I knew what you meant. It's on the list.

I don't find the vapor unbearable unless I hit my toung with the heat stream. The mouth piece does burn my lips though after several quick pulls.

 

[herbivore21]

No problem man, I knew what you meant. It's on the list.

I don't find the vapor unbearable unless I hit my toung with the heat stream. The mouth piece does burn my lips though after several quick pulls.

I find that direct draw hits are really hard on my mouth no matter the temp, too hot to actually use. The hot tip issue happens IMO because the vapor is concentrated into a very narrow path at the tip of the mouthpiece and this ends up in a lot of heat travelling minimal distance from the heater before hitting a very small surface area (leading to the hot tip issue you have experienced) that is in contact with the user's mouth.

This same design also means that given the very short vapor path, the very, very hot air carrying the vapor is entering your mouth when direct drawing in a very narrow stream, concentrating the heat on much smaller area in the mouth.

Both the hot tip on the lips and too hot vapor in the mouth issues will irritate some of us more than others and a lot of this will depend on not only our own biology, but also environmental variables. We seem to both get bothered by different individual effects of this problem more than the other.

What I do know is if you get an 18mm diameter straight glass tube around the mouthpiece and extend it 1.5 inches further, leaving the path open - that vapor becomes noticably smoother. This is not a very portable-friendly setup though.

Something similar to what you've made that is a vapor safe metal, perhaps with a carb hole for additional cool air intake would be game changing in this regard. It would allow for the vapor to get to the fine mouthpiece tip having cooled over more surface and mixed with more external cool air. This should keep the pen relatively discreet (the extender shouldn't need to be more than a few inches if that) still and make it much more usable for a lot of people in direct draw situations by resolving the above issues.

I look forward to seeing what you can do brother, great to see you doing these power mods too - this is a very helpful niche to fill and you know you'll be hearing from me when you got some of these available

 

[Snappo]

@Joel W. - Great work! Do you think my battery powered VK can be adapted for the Grasshopper? It contains (3) 3400mah/NCR 18650 b batteries. I've no experience whatsoever in electronics and wouldn't dare venture the modification myself. Pictured below:

 

[Joel W.]

@Joel W. - Great work! Do you think my battery powered VK can be adapted for the Grasshopper? It contains (3) 3400mah/NCR 18650 b batteries. I've no experience whatsoever in electronics and wouldn't dare venture the modification myself. Pictured below:

What is the lowest output voltage on the VK? If it can hit 4volts or so, yes it might work..

If it does not go that low, you may need to use a buck that @ZC posted above in post 37?

 

[ZC]

The big question with the vk is if it can handle 12+ Amps. Since the vk is designed for logs, which typically use less than 1 amp I doubt they were designed to handle 12. Worth discussing with the person who built it.

 

[Snappo]

What is the lowest output voltage on the VK? If it can hit 4volts or so, yes it might work..

If it does not go that low, you may need to use a buck that @ZC posted above in post 37?

Thanks, @Joel W. and @ZC... will look into each point.

 

[virtualpurple]

@Joel W. I'm constantly rooting for you man! I hope you're able to Nail this down man, because this is just the thing a lot of us need to make the hopper a more flexible and dependable device.

 

[Joel W.]

Thanks, I am still scratching my head as to why one hopper body works perfectly fine but the other does not?

I am pretty sure it's got something to do with the rear end losing the signal that controls the heater through the cord (not fully understanding how the hopper works does not help me but I assume the PWM part uses the body and the battery or my pack, to send signals) but I can't explain why the one hopper works so well?

I will shorten the cord on the next battery pack a bit and see if that helps.

It's a problem, for sure.

 

[Joel W.]

Shortening the cord by half made no difference. hmmm.

Even shorter maybe? Less cells? No wires? I dunno?

 

[virtualpurple]

I'd use that in a heartbeat