She wants a larger horn for the smart car. So, she found this small air horn. Looks easy enough to install, however it operates with a 30A relay. Two questions:
1) Is there somewhere safe on this car to wire this up?
2) If no to the above, would it be acceptable to install it directly to the battery (fused of course); does the smart car electrical system have enough "overage" to power aux. items like this?
That is correct (even though I haven't done the install, plenty of others have.) The stock electrical plug even fits the connector on the new horn - it is truly plug and play. Just need to ensure the opening on the new horn is facing down.
You can also install the Wolo Bad Boy horn through the driver's side wheel well. If you turn the wheel all the way to the left, you can reach the 3 plastic fasteners that hold the liner in place. Remove them and you can bend the liner and slide in the new horn in through there. After you take off the factory horn, you connect the original wires to the new horn and mount the Wolo on the other side of the bracket (closer to the firewall). It's a tight space to work in, but I was able to do it in under an hour in 30 degree weather. (I mention the temp, just in case anyone was wondering about the flexibility of the wheel well plastic liner.) There are also good DIY threads on the SCOA forum.
I would imagine hooking this directly to the battary would work, especially if you had the 2.0 upgrade. I have to use a portable oxygen compressor for my wife and plug it directly into the 12volt outlet, works great. make sure u put an inline fuse
you don't need to take the car apart.. don't need to even take the old horn off... just open the front "hood" panel, and look into where the OEM horn is, unplug the wire harness to it and pull it gently up into the light of day. There, you can test your AIR horn's polarity with the wire harness cables.... Now that you had someone honk the air horn that was in your hands... and scared yourself half to death, put it in a nook under the "hood" and affix it with zip ties. "DONE!"