On a recent trip to the local petrol station, I used the free air pump to bring all four of my tires up to 32 psi. The machine started automatically and ran until the tire reached 32, then stopped itself with a loud 'DING'. I was inspired and thought, "How cool would it be to have a small hand held version of this to use at home?"
This first photo is the car jump starter I've had for several years. It has lights, a set of jumper cables, and an air pump, all built-in. A few years back, I took it over to the neighbor's house to help jump the old Ford tractor. We got it started and immediatly pulled away to go get some work done ... CRUNCH! Forgot we had set the thing down right in front of the front left tire. It got busted up pretty good, but still worked. For a while. Now the battery has died.
I'd never used the air pump as I have an air compressor in the shop. I thought it would make a perfect base for this project so I gutted this unit and took out the air pump and gauge. I realize I could have added a new battery to this unit and had the tool I wanted, but it's bulky and it's beat up. Besides, where's the fun in that?!
These are the parts I took out of the car jump starter unit. ↑
And I tested them with a 12V power supply. Everything is working! ↑
The temporary power supply. ↑
I'm actually gonna build this thing into an old Harbor Freight battery drill. The NiMh battery packs aren't taking a charge any more. Instead of repairing or replacing those, I'm gutting one and refilling it with a 4S2P Lithium battery pack. ↑
Gonna need to remove some plastic from the inside to fit in the new Lithium 18650's. I started out with the new cells staggered but that arrangement ended up being too tall. The battery case wouldn't close with them arranged this way. You'll see in later photos I rearranged them in two flat rows of 4 cells. ↑
The bad staggered arrangement of the new 18650's. Got these from Digikey. I got the ones with the solder tabs and joined them up to produce about 14.8 VDC. ↑
I used my carbide round file on an air grinder to remove the old NiMh separator tabs. ↑
Now they'll fit laying flat in the bottom of the battery holder. ↑
Fully wired including a 4S battery protection board I got from Ebay. Note the new flatter battery arrangement. ↑
Curling up the wires and stuffing it all inside .... ↑
The finished product! ↑
Here is the gutted drill and the air pump pieces I will stuff inside. The plan is to have the drill-shaped air pump with a 3 foot air hose coming out of the end. You'll press that onto the schrader valve, pull the trigger, and air up the tire. ↑
Aww, danggit! It's already been invented. Should I just buy one? ↑
That's it for now. More updates to come as the project gets completed.