Does anyone know what the typical current draw of a car or motorcycle horn is? I'm building a DIY light system using a 12v SLA 7amp battery and wonder if a horn might not fit in my plans as well...
Thanks

I don't know, but they can't pull much and it's used very little, compared to light.

I expect its effect on battery life is insignificant.

Their website doesn't appear to permit direct linking, but Hella's Supertone horn, part number 003399051, is listed as 78 watts, which at 12v is only a 6.5 amp draw. That would squeeze in just under your 7amp battery's specified limits Of course, fact is, you can usually draw 2x of a battery's rated amperage in short bursts, but still, it is good to stay within it's rated range. That horn is a healthy 116db, which is probably plenty loud for scaring the crap out of iPod joggers on a MUP.

Thanks Photosmith!

I have been using a standard car replacement horn from the auto store for years and had no problems. My battery now is a 3.6 Ah SLA (3 lbs), down from a 7 Ah (6.15 lbs), then to a 5.5 Ah SLA (4.33 lbs) (went all LED lights). The horn comes in very handy, especially when people are backing out and not looking carefully! I use a car replacement horn button inside a section of old inner tube for wet weather protection.

Map tester,
Have you been using a Relay with the switch or just battery, switch, horn in series?
Keith