EonSmoke Vape Debris

Being the type of guy who uses metal bits & pieces, I thought this might be a useful aluminum rod:

EonSmoke vape stick
EonSmoke vape stick

It turns out to be an aluminum tube holding a lithium cell and a reservoir of oily brown juice:

EonSmoke - peeled open
EonSmoke – peeled open

The black plastic cap read “EonSmoke”, which led to a defunct website at the obvious URL. Apparently, EonSmoke went toes-up earlier this year after ten years of poisoning their customers, most likely due to “competitor litigation”.

The black cap held what looks like a pressure switch:

EonSmoke - switch
EonSmoke – switch

Suck on the icky end of the tube to activate the switch, pull air past the battery (?), pick up some toxic vapor around the heater, and carry it into your lungs:

EonSmoke - reservoir heater
EonSmoke – reservoir heater

Maybe there’s a missing mouthpiece letting you suck on the icky end, activate the switch, pull vapor through the heater, and plate your lungs with toxic compounds. I admit certain aspects of my education have been sadly neglected.

The lithium cell was down to 1.0 V, with no overdischarge protection and no provision for charging, so it’s a single-use item. I’m sure the instructions tell you to recycle the lithium cell according to local and state regulations, not toss it out the window of your car.

I had to wash my hands so hard

NPN RGB Astable Multivibrator Timing Adjustment

Back in the beginning of July, I replaced the NP-BX1 battery in the RGB Piranha astable multivibrator with a 18650 lithium cell and a USB charge controller, then watched it blink for the next two weeks on the first charge:

Astable - 10 11 12 uF tweak - 027
Astable – 10 11 12 uF tweak – 027

However, the blinks looked … odd and some poking around with a Tek current probe showed the red and blue astables had locked together, so they blinked in quick succession. Alas, I don’t have a scope shot to prove it.

I built all three astables with the same parts, figuring the normal tolerance of electrolytic caps would make the astables run at slightly different rates, which they did at first.

This being a prototype, I just soldered a 1 µF cap onto the blue channel’s existing 10 µF cap:

Astable - 11 uF cap - detail
Astable – 11 uF cap – detail

You can barely make out the top of the additional 2.2 µF cap on the red channel, through the maze of components; now, they definitely have different periods.

Aaaand the scope shot to prove it:

Astable NPN - 10 11 12 uF tweak - 10 mA-div
Astable NPN – 10 11 12 uF tweak – 10 mA-div

The bottom trace shows the battery current at 10 mA/div. The first pulse, over on the left, has the red and blue LEDs firing in quick succession with some overlap, but they separate cleanly for their next pulses.

You don’t want to build a battery-powered astable from NPN transistors, because the 8 mA current between blinks is murderously high. In round numbers, each of the three LEDs blinks twice a second for 30 ms at 20 mA, so they average 3.6 mA, less than half the current required to keep the astables running between blinks. Over the course of 14 days, the circuit drew 11.6 mA × 336 hr = 3900 mA·h until the protection circuit shut it down.

The lead photo shows a harvested 18650 cell, but I started with a known-good Samsung 18650 cell rated at 2600 mA·h at a 0.2C = 520 mA rate to 2.75 V. It’s comforting to see more energy trickling out at a 0.005C rate!

I must conjure a holder with contacts for an 18650 cell, support for a trio of 2N7000 MOSFET astables, and some kind of weird spider with the RGB Piranha LED on the top. Even a harvested 18650 cell should last a couple of months with a much longer blink period (500 ms is much too fast), less LED current (this one is shatteringly bright), and a lower average current.

And, yeah, I’ve been misspelling “Piranha” for a while.

Harvesting 18650 Lithium Cells

With a Dutchess County Household Hazardous Waste Collection Day coming up, I’ve been harvesting usable lithium cells from a variety of old batteries:

Harvested 18650 3P lithium batteries
Harvested 18650 3P lithium batteries

The pile of 18650 3P blocks over on the right are some obviously corroded deaders and the lowest performers from these tests:

Harvested 3P 18650 Packs
Harvested 3P 18650 Packs

I doubt they’ll get recycled, as there’s entirely too much overhead involved in dismantling boxes full of cells like these, but I hope they’ll get a decent burial somewhere.

Motor Starting vs. Long Wires

A recent email conversation may prove relevant to someone else …

I have a pole barn which has approximately 100′ run of 10 gauge copper supplying power to the building. I … did not care to pay … $12,000 for a new 200′ line from the road … [with] only lights and 2 door openers for demand.

I … put a 30 gallon air compressor in […]. When I first put it in, it struggled to start @<40 F. They called it a 1.6 running h.p. (whatever that means) motor. Nameplate shows 15/7.5 F.L.A. I switched it to 240v and the problem went away.

Aren’t I likely to get the same problem as I had before or do 240 volt motors start easier?

I screwed up when they buried the wire – in retrospect I would have buried 6ga to the barn to lessen the voltage drop.

After running a few numbers, here’s what I came up with …

do 240 volt motors start easier?

The trouble with motors is they draw far more current while starting than they do while running. A factor of ten more is a good rule of thumb.

So a “1.6 running HP” motor draws 1.2 kW while running at full load:
 – 10 A at 120 V
 –  5 A at 240 V

The “full load amps” will be higher than that, because the motor isn’t 100% efficient. You can plug the FLA values into the calculation for an even more depressing result.

During the fraction of a second when it’s starting, however, it will (try to!) draw 100 A or 50 A, depending on which line voltage you’ve wired it for.

100′ run of 10 gauge copper

That’s 200 feet of wire out-and-back.

Look up the resistance per foot in a wire table, finding 10 AWG wire has a (convenient!) resistance of 1 mΩ/ft, so a 200 ft length has 0.2 Ω of resistance:

 – A 10 A load drops 2 V
 – A  5 A load drops 1 V

Both of which are survivable in normal operation at their respective line voltages.

However, the motor starting currents will be completely different. A 100 A current will (try to!) drop 20 V, reducing the line voltage to 100 V and stalling the motor. Running the motor from 240 V means the 50 A starting current drops only 10 V and the remaining 230 V can get the motor up to speed.

Now, 240 V service isn’t a complete solution. The new compressor draws 15 “full load amps”, so it’ll drop 3 V while it’s running and 30 V while starting. It’ll probably start at 210 V, but it may grunt for a bit longer than you like as the speed comes up and the current goes down.

in retrospect I would have buried 6ga to the barn

There’s a Pennsylvania Dutch saying: “We grow too soon old and too late smart.” [grin]

USB Charger: Abosi Waveforms

For comparison with the Anonymous White Charger of Doom, I bought a trio of Abosi USB chargers:

Abosi charger - dataplate
Abosi charger – dataplate

The symbology indicates it’s UL, but not CE, listed. Consumer Reports has a guide to some of the symbols; I can’t find anything more comprehensive.

Applying the same 8 Ω + 100 µF load as before:

Abosi charger - 8 ohm 100 uF detail - 100 ma-div
Abosi charger – 8 ohm 100 uF detail – 100 ma-div

The voltage (yellow) and current (green, 100 mA/div) waveforms look downright tame compared to some of the other chargers!

I made a cursory attempt to crack the case open, but gave up before doing any permanent damage. Hey, that UL listing (and, presumably, the interior details) means they’re three times the price of those Anonymous chargers!

Dehumidifier Scrapping

Dutchess County has another Household Hazmat / Electronics Disposal Day coming up, so I harvested some useful parts from the three dead dehumidifiers lurking under the bench.

The (perfectly good) blower motor in one unit lives inside a convenient plastic housing:

Scrap Dehumidifier Blower Motor - housing
Scrap Dehumidifier Blower Motor – housing

It’s sitting on three foam pads hot-melt glued to three wood blocks cut to fit inside three convenient molded features, making it nice & quiet & stable.

The motor uses a nice polypropylene run capacitor:

Scrap Dehumidifier Blower Motor - 6 uF cap
Scrap Dehumidifier Blower Motor – 6 uF cap

Which is also perfectly good:

Scrap Dehumidifier Blower Motor - 6 uF cap test
Scrap Dehumidifier Blower Motor – 6 uF cap test

The motor includes a wiring diagram:

Scrap Dehumidifier Blower Motor - wiring diagram
Scrap Dehumidifier Blower Motor – wiring diagram

I lashed it together with a chopped-off IEC cord, because the stock dehumidifier cords are just way too stiff. The motor and blower originally pulled air through the dust filter, the condenser, and the evaporator, before blowing it out the side, so it’s running pretty much unloaded. A quick test shows there’s not much difference between the high and low speeds:

  • High: 1050 RPM, 80 W, 12.5 m/s air flow
  • Low: 1000 RPM, 77 W, 11.7 m/s air flow

Low speed seems slightly less noisy, but the wiring now has insulated QD connectors just in case I ever want to run it at full speed.

For whatever it’s worth, the most recent dehumidifier failed one year into a two year warranty, but the company decided it was simpler to just refund the purchase price than to replace the unit. It seems the “sealed system” inside loses its refrigerant after a year and there’s no practical way to seal a small leak and recharge the system; unlike an automotive air conditioner, the tubes are soldered shut after the initial charge.

They all sport Energy Star badges, but throwing away the whole damned thing every year or two tells me we’re not measuring the right values. Obviously, somebody could make a worthwhile dehumidifier, but as of now Frigidare, GE Appliances (sold to Haier), and Danby are on my shit list. Next year, I expect to add HomeLabs to the list, because the dehumidifier is identical to the Danby unit (and, ah-ha comes with a 2.5 year warranty). They’re all made by Haier (or another Chinese factory) and nobody applies any long-term QC to their products.