How to use electric bike pump in my home?

[stavcas]

I have an electric bike pump and I want to change the electricity from this:


to this:


or just something that will allow me to use this pump without a need of a car nearby...

Thanks!
~Stav!

[Technician1002]

I have an electric bike pump and I want to change the electricity from this:

to this:

or just something that will allow me to use this pump without a need of a car nearby...

Thanks!
~Stav!

You need a DC power supply with enough current to provide for the peak load the compressor will need. Think wall wart on steroids. Laptop power supplies are often good for only 60 watts and often at higher voltage than 12 volt. To feed that pump, you will want a supply of at least 12 AMPS. Check with Radio Shack for the high current supplies. You won't like the price.
The SL series on this page from Astron should run the compressor;
http://www.astroncorp.com/showpage.asp?p=2

Recommendation is to buy a small AC compressor instead.

[stavcas]

Where can I get a small AC Compressor?
I can buy from online stores but I need them to ship to Israel.

[Biopyro]

Why not just get a car battery and hook it up the 12v socket indoors. It will be more portable than a wall socket, and wouldn't be too expensive.

[jimmy101]

Or, just use a car battery charger. Usually they'll source at least 10 AMPS.

Another possibility is a car emergency jumper battery. They come with a wall wart to recharge, will source perhaps a hundred amps (but not for very long), and often come with both male and female "cigarete lighter" connectors. Lots of oomph in a very convienent package.

[ramses]

computer supplies provide 12v. in America, they are very cheap, and can often provide at least 500W.

here

[Technician1002]

computer supplies provide 12v. in America, they are very cheap, and can often provide at least 500W.

here

True.. That is the total power on all the various voltages combined. Most of the output is on the 5 volt line. Often the +12 volt is limited to only 5 Amps or 60 Watts to drive motors and fans. Read the label or you will let out the magic smoke.

[ramses]

yes, but on a fairly high wattage power supply, current at 12V should be sufficient. on the 300W power supply modded in the link, 12A was (were?) available at 12V. this translates to 144W (VA) or roughly half the power of the power supply. I can't say that the 1250W power supply will have 50A available at 12V, but I doubt these pull that much.

The current rating can probably be exceeded to cover the peaks in current. Otherwise, you could hook up a bigass cap in parallel with the load. These are sold for driving car speakers and are often rated at 12V and more than 1F (1,000,000uf)

[Technician1002]

yes, but on a fairly high wattage power supply, current at 12V should be sufficient. on the 300W power supply modded in the link, 12A was (were?) available at 12V. this translates to 144W (VA) or roughly half the power of the power supply. I can't say that the 1250W power supply will have 50A available at 12V, but I doubt these pull that much.

The current rating can probably be exceeded to cover the peaks in current. Otherwise, you could hook up a bigass cap in parallel with the load. These are sold for driving car speakers and are often rated at 12V and more than 1F (1,000,000uf)

A couple of notes. Many computer power supplies won't work without a load on the main 5 Volt supply. Using only 12 volts can cause failure.

On the big caps, many computer power supplies will go into instant shutdown when hit with the huge current that cap wants to charge. You may need to pre charge it off a wall wart, then connect to the supply.

Check the power supply current limiting. Some simply shut down. Others fold back to a very low current until the over load is removed. Others simply crank out the amps at the current limit setting. There is no standard for over current protection other than there must be some.

[jimmy101]

Like Technician said, most PSUs require some load on (usually) the 5V line or they won't power up properly (or at all).

A cheap and easy load is an incandescent light bulb. A 100 watt light bulb has a resistance of something like 10 Ohms at room temperature. When operating with 120 VAC the heat makes the filament resistance go up to about 150 Ohms.

So, try a couple different wattages of 120 VAC bulbs as loads on the 5V line. You could use a resistor for the load but you need to be able to dissipate a fair amount of heat so a standard 1/4 Watt resistor won't usually work and higher wattage resistors can get expensive. The nice thing about the light bulbs is that they are cheap and can dissipate a heck of a lot of energy without any problems.

Lets see, 5V (DC) across 10 Ohms would be 0.5 Amp, 2.5 watts. That 2.5 watts will warm the filament some, raising the resistance, but not too much (at least compared to the 100 Watts it is designed for).

[ramses]

Like Technician said, most PSUs require some load on (usually) the 5V line or they won't power up properly (or at all).

this is mentioned in the link, as well as some sensing thing that connects to the 3.3v or 5v line. I suppose the cap isn't a great idea, but whatever. If it was necessary, it could be connected via a resistor with a switch to short it (the resistor) during normal operation.

[stavcas]

WOW Guys!
Thanks for all the good answers
I'm using a PSU and it's going well!
BTW I really like the community here!
Thanks again Guys!
~Stav!