home improvement turns into science fair projects?

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mediatechnology
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Re: home improvement turns into science fair projects?

Post by mediatechnology » Wed Nov 13, 2019 7:39 am

Can you just use a ubiquitous USB charger?
Most are at least 15W.
Or buy a fancy USB/120V Nema outlet...
https://ka-electronics.com

"5G Launches In Wuhan Weeks Before Coronavirus Outbreak" https://banned.video/watch?id=5e335e772f3c020019a423f8
"Biggest Medical Scandal In History Breaking! UN Comes Clean, Admits Vaccine Death/Damage Coverup" https://banned.video/watch?id=5e1b9ed434b802001ed99b14
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JR.
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Re: home improvement turns into science fair projects?

Post by JR. » Wed Nov 13, 2019 9:55 am

mediatechnology wrote:
Wed Nov 13, 2019 7:39 am
Can you just use a ubiquitous USB charger?
My suspicion is that may be the problem, the charger ICs can have protection circuitry to prevent overcharging phone batteries.
desc wrote: Comprehensive Safety: CE/FCC certificated, Built-in safeguards protect your devices against excessive current, overheating, and overcharging. The wall charger will automatically stop charging when power is full, which can maximumly protect your device

Most are at least 15W.
I just looked again and one 15W unit I saw had 3 USB connectors.Image My suspicion it is 15W total not per.
Or buy a fancy USB/120V Nema outlet...
I have another similar USB plug-in unit on order. I expect the USB outlets use the same switcher chip sets inside.

JR
Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.

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mediatechnology
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Re: home improvement turns into science fair projects?

Post by mediatechnology » Wed Nov 13, 2019 10:20 am

They're usually 15-20W total.
TI has a nice chipset for this function that supports fast charge (9V) and its various signalling methods.
https://ka-electronics.com

"5G Launches In Wuhan Weeks Before Coronavirus Outbreak" https://banned.video/watch?id=5e335e772f3c020019a423f8
"Biggest Medical Scandal In History Breaking! UN Comes Clean, Admits Vaccine Death/Damage Coverup" https://banned.video/watch?id=5e1b9ed434b802001ed99b14
Mirror/Download: https://proaudiodesignforum.com/content ... overup.mp4
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Re: home improvement turns into science fair projects?

Post by JR. » Wed Nov 13, 2019 11:41 am

After I get my replacement I may take this first one apart. If the replacement works fine, to see what went wrong with faulty unit.

If the replacement has similar cold temperature misbehavior to see what chip is used and try to find data sheet.

Alibaba sells the finished unit for $0.50 in large qty.

JR
Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.

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Re: home improvement turns into science fair projects?

Post by mediatechnology » Wed Nov 13, 2019 12:38 pm

So the material cost is what, 8 cents?
https://ka-electronics.com

"5G Launches In Wuhan Weeks Before Coronavirus Outbreak" https://banned.video/watch?id=5e335e772f3c020019a423f8
"Biggest Medical Scandal In History Breaking! UN Comes Clean, Admits Vaccine Death/Damage Coverup" https://banned.video/watch?id=5e1b9ed434b802001ed99b14
Mirror/Download: https://proaudiodesignforum.com/content ... overup.mp4
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Re: home improvement turns into science fair projects?

Post by JR. » Wed Nov 13, 2019 7:06 pm

mediatechnology wrote:
Wed Nov 13, 2019 12:38 pm
So the material cost is what, 8 cents?
My experience with large Chinese contract manufacturers is that they operate on pretty narrow margins. I would not be surprised about a BOM $0.25 to $0.35. I've seen some pretty skinny profit margins.

That's why they envy (and sometimes purchase) western brands making fat profit margins.

JR
Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.

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Re: home improvement turns into science fair projects?

Post by JR. » Thu Nov 14, 2019 10:34 am

Good progress integrating my blower (air mover) into my winter heating program.

For a couple years to save money I would only heat my bedroom at night using a time of day thermostat and resistance baseboard heaters. Now that I have a big dog (2T) heat pump heating/cooling my main room, I have experimented with sucking air from the main room to heat/cool my back bedroom.

I determined that the blower I bought (on sale) was way too high capacity for comfortable use. I figured out how to slow it down with capacitors in series. The instructions advise against using solid state speed controls.

I tried to use just the blower with my TOD thermostat, but it draws power through its load, and the blower was too light of a load. It requires a minimum 2A load. I had previously upgraded from a 1kW baseboard heater to 1.5kW when the 1kW was marginal output for cold winter nights. For chuckles I wired the 1kW in series with the 1.5kW, making a combined 500W load, drawing adequate current to power the TOD thermostat. Since the two baseboard heaters in series form a voltage divider, I can power the blower from the lower voltage or higher voltage fraction. On the higher voltage leg, I could hear a tone coming from the blower. The thermostat has 5 levels of heat output (likely PWM) that caused audible noise from the blower motor. On the lower voltage leg the noise was not audible and the blower still moved enough warm air from the main room to heat the back bedroom... This morning with overnight lows in the 30s the bedroom temp was well regulated and heat/blower alternately running (silently) at only 40% power...

I experimented with making a simple RC LPF using the junction of the two baseboard heaters as the R. I estimate about 5 ohms source impedance at that node. The only cap I had laying around that I felt comfortable using at that voltage was a 22uF, and it did not eliminate the noise (from high voltage leg). So one pole LPF -3dB at 1.4kHz does not quiet it down significantly.

Not a problem, blower runs silenty on lower voltage leg. I will need a different plan for cooling next summer, but no need to worry about that for several months.

JR

PS: This morning my laundry room greenhouse temperature was still well regulated to 50', while grow lights were locked up again, but I was able to reset them. Still waiting for replacement USB supply to suss that fault out. Not only did my pepper plants not freeze but I see two new bell peppers coming. 8-)
Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.

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Re: home improvement turns into science fair projects?

Post by JR. » Fri Nov 15, 2019 11:43 am

Just received my replacement USB charger so lets see if I had a personal problem with one faulty unit, or have a design problem.

I notice the package for this new unit says "for indoor use only" while my laundry room is technically indoors, just not heated.

It is in place and working, exposed to the laundry room temps (warmer than outside but still gets cold). Forecast for tonight predicts another night in the 30s so we'll see soon enough. :lol:

JR
Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.

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Re: home improvement turns into science fair projects?

Post by mediatechnology » Fri Nov 15, 2019 12:20 pm

"for indoor use only"
Sometimes reads "Not for damp locations."

Good luck.
I bet it runs overnight this time.
https://ka-electronics.com

"5G Launches In Wuhan Weeks Before Coronavirus Outbreak" https://banned.video/watch?id=5e335e772f3c020019a423f8
"Biggest Medical Scandal In History Breaking! UN Comes Clean, Admits Vaccine Death/Damage Coverup" https://banned.video/watch?id=5e1b9ed434b802001ed99b14
Mirror/Download: https://proaudiodesignforum.com/content ... overup.mp4
More: https://proaudiodesignforum.com/content ... People.mp4

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JR.
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Re: home improvement turns into science fair projects?

Post by JR. » Fri Nov 15, 2019 12:34 pm

mediatechnology wrote:
Fri Nov 15, 2019 12:20 pm
"for indoor use only"
Sometimes reads "Not for damp locations."

Good luck.
I bet it runs overnight this time.
That is my hope, but we'll see. :lol:

JR
Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.

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