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Need electrical advice! (air pump)

4K views 25 replies 13 participants last post by  tiger3 
#1 ·
I mounted my air compressor inside the jeep. I op tested it and it worked fine (a few seconds). I ran a wire from the plus on the battery and another to ground. Ran the wire to behind the seats where the pump is mounted. The pump originally was a portable type I connected directly to the battery. I cut the majority of the pump's original cable and to make the connection, I spliced a quick release connector on a short piece of the same type wire I ran from the battery. I want it to be removable. I had to do this because the wire that comes from the air pump was too large to use the with the quick connect. It worked, but I had not tested it actually filling a tire. Well when that time came, the pump did not even get a single tire aired up when I saw smoke coming from the wires. It also seemed like it was not working at full capacity. It would normally air up a 35 in 3 min.

So now I am wondering if the wire I used is too small or is it because I did not solder it inside the quick release connector. It melted the wire covering on the pump side the wire going to the battery is ok. The pump is a 12 -13.5 volt 45 amp pump. Any advice on how to fix the wiring so it will not burn would be appreciated!!!

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#3 ·
No inline fuse used. I assumed I did not need one since the original way to use the pump was direct battery connection. It has a reset button on the pump. I am not sure if that is fused.

Here are the two different size of wires. I am not sure what gauge. I cannot find that info stamped on the wire. Before I put in the hardwire, I connected the red connector to the battery and the switch for it was on and it started. So it is grounded by the way it is mounted.
Everyday carry Tool Finger
 
#5 ·
That wire looks way way too small to me. Plus the connector may not be making a solid connection and bottle necking the current.

If that pump is rated at 45 amps, the minimum gauge of copper wire at 76*C is 8G. That's rated for 50amps and is probably the size that is coming out of the pump. I would over size the wire and run 4 gauge wire. But I wouldn't put a connector on it like that unless you find a properly rated 45amp connector. If you run it straight from the battery it will arch like crazy when you push the connections together.

The proper and simplest way to do this would be to run 4g wire straight to the batt and put some alligator clamps on the positive and negative wires. Then when you need the pump just pop the hood and connect the clamps.

If you want it permanently inline and switchable, with either a quick connect or a rocker switch, you'll have to use a relay.

A relay runs a small current to the switch that way it doesn't arch or heat up when the switch is thrown, then it routes the full amount of juice to the accessory. This way the full load of the battery isn't being held in the switch/connection wire.
 
#6 ·
That wire looks way way too small to me. Plus the connector may not be making a solid connection and bottle necking the current.

If that pump is rated at 45 amps, the minimum gauge of copper wire at 76*C is 8G. That's rated for 50amps and is probably the size that is coming out of the pump. I would over size the wire and run 4 gauge wire. But I wouldn't put a connector on it like that unless you find a properly rated 45amp connector. If you run it straight from the battery it will arch like crazy when you push the connections together.

The proper and simplest way to do this would be to run 4g wire straight to the batt and put some alligator clamps on the positive and negative wires. Then when you need the pump just pop the hood and connect the clamps.

If you want it permanently inline and switchable, with either a quick connect or a rocker switch, you'll have to use a relay.

A relay runs a small current to the switch that way it doesn't arch or heat up when the switch is thrown, then it routes the full amount of juice to the accessory. This way the full load of the battery isn't being held in the switch/connection wire.
^^^^^^^^^^^This.....Just reinforcing what Bent has said, and will add
"Never go with a smaller wire gauge than what was supplied from the factory"
 
#7 ·
I think Bent Jeep may be correct on the wire gauge being too small.
Here is a link to a page that has a chart for how to select wire size, based on your voltage, and currant draw, and lengh of the wire. This counts the total lengh, from the battery, to the pump, and back to the battery.

DocThrock's Team Rocket F1 EVO Electrica Wiring

Keep in mind using larger wire is safer then smaller wire
 
#9 ·
One other thing Bent jeep didn't mention is that I would never run anything that doesn't have a fuse on it. Whether it's an air pump, a sound system amp, lights, etc. Accidents like you just experienced are going to happen; all you can do is plan for them. The fuse will drastically decrease your chances of having to replace the wiring, the component or even the entire vehicle (unchecked electrical currents can easily start fires). Just my two cents though.
 
#11 ·
Looking at the connector with the burnt wires, you can see the heat source. Where the yellowing mark is at. I'd say you had a bad connection. You need a larger connector rated over 45 Amps. And get some better wiring. You can google the wire size in Gauge and to Amps used. And if you know how to use a voltmeter, next time read the Voltage on both sides of the connector and see if there is a difference. And that's the problem you had. A real big difference. And after you run new wiring and test the pump, you should feel the wires and connector and see if they are warm or hot. YOU ARE PLAYING WITH FIRE! KINDA LIKE A TOASTER YOU MIGHT SAY. I have to ask, why would you run smaller wiring to larger wires.
 
#12 ·
The spark seem before the connector like if the wire was pinch by your seat rail or something like that. Use at least the same gauge that original and if you extend the wire, you need to upgrade the gauge following the chart. And yes, you need a fuse near your power source(battery): if your wire get cut by anything you will be safe = no jeep in fire! Are you sure for the 45amp(seem huge)? Viair 450c is rated 23amp...
 
#16 ·
Got some larger wire (larger than original) and connectors. I also got a 30 amp inline fuse. I tested it again, but just as the pump filled the tire to capacity. About 40 psi. The fuse blew. :nonono: The pump was putting out some air this time and seemed to be back to normal speed in filling a tire.

I am now in search of a 40 amp fuse to put in. I think a 40 amp should do the trick (fill a tire without blowing the fuse) so I can do the other 3. LOL. Problem is finding that fuse here is a pain; Japan.
 
#17 ·
In your first post you state the pump draws 45 amps. That's why it blew the 30 amp fuse. It will blow the 40 amp one too.

Use the specifications from the pump and size everything correctly. Wire connectors, fuse and fuse holder.
 
#18 ·
In your first post you state the pump draws 45 amps. That's why it blew the 30 amp fuse. It will blow the 40 amp one too.

Use the specifications from the pump and size everything correctly. Wire connectors, fuse and fuse holder.
^^^^^^^^^^^^^This is correct; you must fuse to match the load!
And for 45 amps, I would be looking at a circuit breaker instead of a fuse, because the fuse will probably pop at 45.5 amps where the breaker would allow for a momentary overload.(Like starting under a load)
 
#21 ·
Thanks for the advice, what I have read you should under fuse. That way the weak link will be the fuse near the battery. If I cannot get the fuse holder for 45+ amps locally I will have to order that one from Amazon. I would like to find the fuse local to me so I can replenish them easily.
 
#22 ·
You never under fuse, if you do you keep poping them. Correct size is just over the max draw of the equipment.

A fuse is not used to protect the load device, they are to open the circuit if a short occurs and prevent a very high current flow in wires not designed for that load. (They keep wiring from getting too hot and starting fires.) Under sizeing the fuse is not needed for this, correctly sizing components lets you run trouble free.
 
#23 ·
OK, so I need to get a 50amp fuse. I looked today, at many auto shops here, but was unable to find anything over a 30amp. Looks like I will have to order the right one.

I also have verified that the pump has a built in circuit breaker. Given this, do I still need to fuse the line?
"Resetting Circuit Breaker: (Part #2781)
The circuit breaker is located next to the on / off switch on the top of the rear housing. During normal operation it remains in the down position almost even with the base. In the event of and overload it will pop- up. If this happens, turn the power switch to off, disconnect the air hose and power cord. Push the breaker down to reset and resume operation."
 
#24 ·
Yes you still need a fuse near the battery. The circuit breaker only protect the pump. It doesn't shut power off in the wire from the battery to the pump. Without a fuse any short in that wire will result in a possible fire.

☞Sent from here☜
 
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