Tales from a Ventilation Lunatic

[sternwake]

I played with some 2, 3, and 4 series 18650 holders and various fans. Getting a better feel for potential size in pocket, air moved, for noise made and wattage drawn.
The 60mm delta on 2 18650s, @ about 7.5 volts, is a respectable amount of flow and quite small in pocket. Still an annoying pitch though. Definitely an effective wet Fiona belly fan, but if she is overheating then more flow mo betta, but any flow better than no additional flow. draws about 0.5 amps.

The 50mm Deltas zip tied together at 12.0 volts is about the same overall flow volume, not velocity, and amp draw, but not worthy of consideration, at 7.5 volts.

The 18650 holders have pathetically thin wiring, and crappy interface between battery contacts and that too thin wire. I was measuring way too much voltage drop, and the wires were getting
too hot at far less than 35 watts. I got some ideas to reduce their resistance, but not today.....



I ordered another Delta PFB0912dhe, 92mm 3.52 amp 12vdc fan, 7500 rpm@12vdc, which arrived today, and have 5 or 6 XL4005 voltage buckers on hand.

Its minimum start up voltage is 4.82ish volts.
This changes slightly with ambient temp, and if the fan is already warmed up, thus the 'ish'.
I removed the trimpot from XL4005 Vbucker at 4.82 V out, and measured its resistance: 0.782 K ohms.

I fired up a different xl4005 bucker on the ridgid battery measuring 20.5v, and dialed voltage to 14.28v, about the maximum I ever want this fan to see. I desoldered trimpot and measured its resistance, 2.782 Kohm. Was surprised at the nearly perfect 2K ohm range, from 0.782 to 2.782, yielding 4.86v to 14.28v. minimum delta speed to Maximum.

Yeehaw.

So basically I need to order 2K ohm potentiometers. I will add any removed trimpot in series with it, to dial in .782 K ohms minimum, for delta start up minimum rpm, and then the 2K ohm fingertwist pot will allow me to dial up speed/voltage to no more than 14.28v on the fully charged 20.5x volt Ridgid battery. full speed range, no overvolting
of fan possible.

If I feed lesser voltages to the bucker via 12.6 or 8.4v battery then the max voltage will be about 0.3v under battery voltage.

So basically If I order 2K ohm potentiometers, I'm golden to use protected ridgid battery to power pocketable fan.

I could also just use the triple 18650 holder, which is a max of 12.6v. The triple 18650 holder is much lighter, smaller, than the 2.0Ah ridgid battery, but I can overdeplete the 18650s, damaging them.
Not sure I want to take measures to automatically prevent overdepletion, or if it is going to be a factor in compact pocket fan duty. Just need a small voltmeter, not let it go below about 9 volts, though the minimum cutoff voltage on the Ryobi cells is 2.5v.

I did use my 150 watt DC to DC voltage booster to charge the 18650s in series, in the holders, but charging at 4+ amps the wires and contacts just get far too hot too quickly so I tabled that experiment for now.

I ordered some small 2 amp voltage boosters, for some USB power supply nightlights, but what arrived are 3 amp LM2596 voltage buckers that I find far less impressive than the 5 amp XL4005 buckers.

This booster can potentially boost a Single 18650's voltage through full delta voltage range.

[sternwake]

Regarding low voltage cut off of a 3series 12.6v battery, i have 2 Orbitronics 18650 cells.

Protected cells. They have a little circuit board on battery top that opens the circuit if cell voltage exceeds 4.35v, or falls below 2.5v, or current exceeds 10-12 amps.
They use the panasonic ncr 18650b cell.

I have 2 basic unorotected ncr18650b cells of about the same age.

My thinking earlier was, use the ryobi battery pack pulls as they are matched cells, but Im expecting to reharge the 18650s separately, not at 12.6v inside 3S holder.

One protected orbitronics cell in series with 2 pannys, 'should ' prevent drawing the other 2 cells below their 2.5v minimum cutoff voltage.

I guess i gotta see how close in capacity the orbs and pannys are, if the bare pannys are much worse they'll drop below 2.5v minimum, before theprotected orbys will.

I could use 2 orbys, and i have one more protected cell whose.protectikn specs.i need to investigate loser. IF i charge them all individually i guess thats the way to go.

[sternwake]

I coukld not find the protection specs for my thrunite protected 18650, but assumed it was a 2.5v LVD.

I put one fully charged orbitronics, the thrunite, and an unprotected panny cell into the 3s 18650 holder, and powered the jaro fan through a wattmeter. Dialed it uoto abiut 0.5 amps at 12.03v.

Right around the 4 hour mark, i saw voltage quickky falling from 8.33.

I tested each cell individually under load, and they were all close, but the unprotected panny was lowest, and when it fell below 2.47 i said screw it, and went to unplug the anderson powerpoles between fan and wattmeter, when the wattmeter went dark.

The orbitronics LVD protection circuit kicked in, and the battery read 0.00v. The other 2 batteries, with load removed were 2.7v range and climbing.

The orbitronics cell in my thrunite C2 charger started accepting 1.56 amps.
So Conclusion.
The 3 series 18650 holder will work as a pocket fan 12.6v max battery, but each cell should be a protected cell with its own LVD.

My orbitronics cells are 9 years and 5 months old. The panasonics a little older. They seem to have about 2150 of their original 3400 mah capacity, remaining.

They powered the jaro fan at 0.5 amp load, for 4 hours, though that had i creased to 0.85 amos when bTtery voltage fell to the mid 8 range.

The compact pocketfan idea is basically never going to require long term use. New 18650 cells would perform far better, the 2.0ah 18v ridgjd battery, even more so, and the 4.0 Ridgid battery is still pocketable too, but the 3 cell holder is way smaller and lighter than the ridgid baTtery

I would have ai.ed fan at fiona belly on todays walk, if i had it. She will stopand seek shade wellbefore the tongue starts hanging low.

I would have finshed fan earlier but need a worktable inside a conditioned soace.
The garage is too fvking hot ezpeciLly with recently driven car inside


The 2k ohm pots arrived. The one i tested read 2167 ohms dialed all the way up.



The cheap 3S holder drops so much voltage, i ordered a better one, with thicker brass contacts bridging battery contacts.

[sternwake]

Decided to finish building the 92mm pocket fan
As low profile and as compact as i coukd add the bucker and wiring and oot to and from it.

Then in abject moment of self destructive stupidity, chose to test it with r 20.22v Ridgid battery instead of a 12v battery.

The tiny 10k Ohm nline trimpot was cranked up. I thought it was the one I'd dialed to exactly 782 ohms, but did not double check.
Plug bucker in. Nothing. Disconnect fan then notice smoke wafting from its hub.



Only after shooting my foot, did the dmm come out and measure 17.82v with fingertwist2k ohm pot dialed all the way down.
Dumbass.
Another 25$ wasted.

So i transferred bucker to high oitched 60mm delta fan.
Dialing minimum voltage to low 3s, the 2k ohm fingertwist pot allowed Ridgid voltage as high as 13.76v. FaN claws itself across table at that voltage, balloons sweaty shirt into michelin man mode when hooked under bottom and i get chilks shortky after.

My 15 watt 8-23vdc USB -C convverter is exact same width and height as delta fan side,. So i attached it to the side.
Its parasitic draw is under 0.01 amps, likely in the 0.005 amp zone, so basicaLly not a factor.

So i can charge phone as fast as possible anytime i have 60mm delta fan plugged into any live anderson powerpole i own.

But the 92mm delta's flow is unparalleled, So i ordered another..
Hopefully i wont smoke this one too.

The 60mm delta is certainky more pocketabke, and i can use it on a 3s 18650 holder too and lose only a few hundred rpm , compared to 18v Rdgid battery.

So one pocketfan prototype is now ready to go, and it can also charge my phone as fast ss it can be charged too.

[rvpopeye]

The expense is a small price to pay for the knowledge gained.
You're just product testing components.....
I have no doubt when you perfect this you could sell the fans if you wanted to !

[sternwake]

Smoking the fan was a rookie mistake.
If i did not have a miillion other projects and the fan was uNOBbtanium, id consider surgery on it.
But now its just an extra impeller and bearings and some 22awg wires.

Selling something requires a level of idiot proofedness of the product okayed by a lawyer who wouLd love the chance to defend.

Screw today's average hyper entitled, always a victim, consumer.
I want nothing to do with them.

The E6000 amazing goop alternative is stinky, far too long, and is stiffer than amazing goop.

The xl6009 voltage booster is working well as my USB wall wart powered red night light. Still unrefined

I stuck it in a louvered, low on the wall Hvac Return vent next, to outlet where a warm white obnoxius night light has lived for years, aimed at white tile floor. Leds themselves invisible to the eye.

Mom loves it. I should dim it a bit more.

I like keeping all my nightvision, and am going to make more.

The 60mm pocketfan is certainly a little powerhouse. With other fans running nearby, its annnoying pitch is subdued.
Its also the fastest usb charger i have. Ive got adapters so usb c male is able to charge usb mini devices and an adaoter to plug in a regular usb A cable. Like for the magnetic tailcap charger of one my brightest headlamps.

[rvpopeye]

Pushing gear to and beyond it's printed limits is the only way to verify it's actual limit.
Intentionally (or unintentionally) I have been there and way more than once . There is a cost , but the knowledge learned made me better at what I did.. Besides , I met some great repair techs and learned even more from them ! (Like , what to carry redundant extras of in the kit. skuh kuh kuh kuh).

[sternwake]

Failure is how one learns best.

But this latest failure was just lazy subconscious selfdestructive dumbassery.

All my loose trimpots are gonna get dialed all the way down.

I am running a xl4005 bucker to charge a single AA eneloop I soldered into some beard clippers.

Charge voltage is much higher than expected.
The xl4005 is rated at 5 amps, and when i switch on clipper motor at charge voltage i saw 7.5 amps flowing through it.

Had another loose AA trimmer, and tried it with a lithium 4.2v 14500. It threw the moving portion of the blade across the bathroom, but was zipping through stubble at an impressive rate until then.

[rvpopeye]

Things tend to slip by from time to time .
I don't think I ever totally escaped soldering up a connector and realized the cover wasn't put on first completely despite doing it thousands of times ,,,maybe because of ? LOL
I long ago stopped beating myself up for those minor casualties easily replaced.
More important things to stress about like the show..

Video some of your show time with mom, you'll have it forever.....

[sternwake]

New 92mm delta arrived unexpectedly today.

But some white zinsser Primer is now stinking up garage, and im outta beer,
And moms decided to drive me and my dad and Fiona nutz, and i want to lock my bedroom door, jump out the window and run away screaming.