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Buckthorn
Stranger

Registered: 07/25/08
Posts: 4,538
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Re: 9V battery engineer experiments? [Re: redchigh]
#28578447 - 12/11/23 11:09 AM (1 month, 16 days ago) |
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How many hours a week did the battery last you?
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redchigh
Mega n00b

Registered: 07/29/13
Posts: 53
Last seen: 9 days, 22 hours
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Re: 9V battery engineer experiments? [Re: Buckthorn]
#28578539 - 12/11/23 12:49 PM (1 month, 16 days ago) |
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Just a few hours.
I used a 12v small appliance dc adapter at the time, the 9v was a backup. Theyd run about half a day at decent speed.
I used a 2 battery portable handheld fan once, but the vibrations knocked it down and it broke a specimen.
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koraks
Registered: 06/02/03
Posts: 26,667
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Re: 9V battery engineer experiments? [Re: Buckthorn]
#28579520 - 12/12/23 03:48 AM (1 month, 15 days ago) |
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Quote:
Buckthorn said: How many hours a week did the battery last you?
Taking a theoretical angle: the capacity of a 9V battery is typically 400-500mAh. A typical 80mm PC fan draws something like 150mA or thereabouts. Theoretically, this will give you maybe 3 hours of fun. However, as the battery discharges, voltage drops and at some point it will drop below the voltage where a 12V fan will run. So in reality, you may get less than 3 hours from that same battery and fan combination.
What helps is that the fan will draw a little less current than its nominal rating if you run it at a lower voltage, so this stretches it a bit. Also, if the fan is already running, it tends to keep running at even fairly low voltages; many computer fans will keep running at around 5V although they won't start at that voltage. So you may notice that after a few hours, the fan stil runs, but if you disconnect it and reconnect it, it'll refuse to restart.
For an static, indoor setup, a wall wart/adapter is a more sensible idea as pointed out earlier.
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gopher
Coffee Bean Extraordinaire



Registered: 11/22/17
Posts: 12,990
Loc: Canada
Last seen: 11 minutes, 58 seconds
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Re: 9V battery engineer experiments? [Re: koraks]
#28580309 - 12/12/23 06:01 PM (1 month, 15 days ago) |
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You can get rechargeable lithium 9v on amazon, but I think I read somewhere that they are actually less than 9v the way lithium batteries work
-------------------- For most of the normies out there, an operating system is just a bootloader for Google Chrome. Since Disney has obtained tremendous value from the public domain, knows how important the public domain is, and is firmly determined to never contribute anything to it. My pronouns are He and Him, and my adjectives are Fat and Jazzy
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Buckthorn
Stranger

Registered: 07/25/08
Posts: 4,538
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Re: 9V battery engineer experiments? [Re: gopher]
#28585594 - 12/16/23 04:01 PM (1 month, 11 days ago) |
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How could I invent an aroma-oil diffuser using these wirds? WHDTS 20mm 113KHz Ultrasonic Atomization Maker Mist Atomizer DIY Humidifier with PCB 3.7-12V https://a.co/d/fVzBEuN
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koraks
Registered: 06/02/03
Posts: 26,667
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Re: 9V battery engineer experiments? [Re: Buckthorn]
#28586271 - 12/17/23 02:12 AM (1 month, 10 days ago) |
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Quote:
Buckthorn said: How could I invent
Dude. Just recreate what's shown in the last picture of that ad/item. It's literally shown there.
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