How to pump your Tyre with a computer! - Page 1
Forum section: electronics / general

author: abdullahseba
author_rank: Frequent Contributor
timestamp: August 04, 2015, 06:52:15 pm
content: Anyone ever done this?We don't have car and the 12v PSU I use-to use for powering the pump was a cingwish one with bad overload protection that it powered the pump... until it stopped working.So when I needed to pump my Tyre I tried a good 12v 4A PSU. But no good the overload kicked in so I tried a another 12v 5A... still no good.I didn't have anything higher so after a good think I tried it on one of my 15-20 odd computers (lost count you see) and it worked on 5v but it was to slow. Perfect on 12v.

author: electr_peter
author_rank: Unknown
timestamp: August 04, 2015, 07:13:30 pm
content: Interesting use of PC's PSU, that for sureHow much power/current does that air pump require? If 5A was too low, would 10A or more be enough? ~10A at 12V makes it >120W item - I expected much less power is needed (I tend to use hand pump for bike tyres).

author: abdullahseba
author_rank: Frequent Contributor
timestamp: August 04, 2015, 07:50:34 pm
content: Quote from: electr_peter on August 04, 2015, 07:13:30 pmI am not sure how much it draws. I broke my hand pump when I was younger by turning the bicycle pedal upside down and sticking the pump through the wheel spokes which broke the pump

author: hexreader
author_rank: Frequent Contributor
timestamp: August 04, 2015, 08:12:48 pm
content: Went through exactly the same exercise about 3 months ago. 5A current limited bench supply only managed about 8Volts at 5A which got the bike tyre partially inflated, but pump gave up well before the required pressure.Computer PSU worked perfectly (with the green wire shorted to 0V black wire), but I have not measured the current draw.

author: 128er
author_rank: Regular Contributor
timestamp: August 04, 2015, 08:33:59 pm
content: Thumbs up for that hack. Have to do the same for my metallurgical microscope. It has a 100W/12V lightbulb. My dual output benchtop PSU was not capable of that. Now my old Pentium 4 machine stands right next to the microscope, only for this purpose.

author: McBryce
author_rank: Super Contributor
timestamp: August 04, 2015, 08:36:07 pm
content: What OS did you use.McBryce.

author: AndyC_772
author_rank: Super Contributor
timestamp: August 04, 2015, 09:56:46 pm
content: I've tried to power a car tyre pump with a 12V SMPS, like a laptop supply.It didn't work; although the mean current draw was well within spec (about 10A IIRC), the pump draws a pulsed load with peaks which the SMPS couldn't manage.Best stick to using a car battery, IMHO.

author: jh15
author_rank: Frequent Contributor
timestamp: August 05, 2015, 01:50:47 am
content: so if you get a flat 20 miles from home, you have no pump in your bike bag?

author: TerraHertz
author_rank: Super Contributor
timestamp: August 05, 2015, 06:44:00 am
content: You can make a short adapter hose from a car tyre valve to a bicycle valve (usually the same.)Then you have an air source where ever there are parked cars.

author: abdullahseba
author_rank: Frequent Contributor
timestamp: August 05, 2015, 10:19:25 am
content: Quote from: McBryce on August 04, 2015, 08:36:07 pmLOL bicycles7