ItsJustMe

To get the same amount of sound out with half the voltage, I assume it needs twice the current. This might wind up being a wash if the battery is properly sized in both cases.

2_i 

My system is intertwined. The dynamo charges the battery and both power the lights and horn. Everything is 6V.

Carib Can

i build and fly RC gas and battery powered aerobatic airplanes, batteries are all lithium ion so I have all the chargers and balances for them. It would be much easier and more efficient for me to use the RC related stuff.

Carib Can

[QUOTE=ItsJustMe;16198662]To get the same amount of sound out with half the voltage, I assume it needs twice the current. This might wind up being a wash if the battery is properly sized in both

You can have a a six volt horn sound louder with less current draw compared with a 12 volt horn drawing more current depending on the design between the two horns.

If the horn had a 6 pr 12 volt selector on the same horn, 6 volts would require more current to produce the same sound level than using 12 volts.

If you do have a device which is designed to work on two voltages via a switch, say 110 vac and 220 vac, the choice of lower voltage requires more current on the same device.

01 CAt Man Do

[QUOTE=Carib Can;16199482]This is not necessarily true. Depends on the power requirements of the actual device. If the horn requires 4A@6VDC to function to reach the proper power level and is designed to work with 6 or 12 volts you just need a voltage source capable of providing 4A@6volts. That said it stands to reason that the only thing the 12 volt switch does is provide a voltage step-down circuit that will allow the unit to function using 12 volts without burning out the other circuits within the unit that are designed to work off of 6 volts.

When you plug your Phone charger into you car cigarette plug this is in essence what is happening; The phone battery only needs so much current and so much voltage to get the job done. Basically what you get with your 12 volt phone adapter is a voltage and current regulator in one. It will charge your phone faster than your computer USB outlet only because it has been designed to supply a bit more current than what typical computer USB ports were designed for. Otherwise, the voltage/current has to step down the same way or risk frying your phone.

Carib Can

[QUOTE=01 CAt Man Do;16203737]You are missing the whole point

As I said, current draw of a device goes up when voltage goes down, so if a device uses 2 amps at 220v that current draw will go up if it had a secondary winding for a 110v selectable circuit.

Look up Ohms law to learn a bit about current, voltage, resistance and power.

As far as phones goes, NiCads and NiMh were only limited to voltage since they took only the current they needed to be charged, they still had to have a maximum current tolerance on the charger, typically 10% of the rating of the battery.

Li Ions and Li Poly (in today's new phones) has to have both voltage and current limiting circuits since they will burn if charged with constant voltage and constant current.

I am an electronic tech by profession BTW

Don't want to go off topic here.


So, I used my Hornit yesterday and it unfortunately, it won't cut it for motorized vehicular driver attention.

It sounds like a malfunctioning car alarm on a weak car battery. I will take it back and rig something up from maybe a 6volt moped horn running two lithium ion cells rated at 1500mA and a voltage regulator.

NOTE: Cold temperatures kill Lithium Ion batteries.

The Hornit is OK for other cyclists, pedestrians and motor cyclists, it won't work for cars, vans etc.

I can actually use a decibel meter to compare before even trying it.

Carib Can

The air horn is no doubt louder and maybe lighter. I looked at its design in the lbs. It seems OK however the valve it uses is just a plastic hose pincher which is not the best.

On cold days the diaphragm might not work. If you are concerned about pumping the air cylinder, you can rig up your own cylinder and use a small air compressor to fill it. You WILL HAVE TO REGULATE THE AIR PRESSURE VALVE ON THE COMPRESSOR IF NOT YOU WILL BLOW UP THE BOTTLE/CYLINDER IF ITS PLASTIC.

Carib Can

Can't find 6 volts horns new, 12 volts are around, light and cheap, however the lithium ion 4 cell batteries are out of this world in pricing.

I will more than likely get an Airzound horn, do some mods and post what I did.

2_i 

US source / UK source

Carib Can

Thanks for the links. I wonder why the US horn states 6-12 volts and the 1.5A current draw is at which voltage. I am thinking that at 6 volts it's draws 1.5 amps for that size horn.

I will call them tomorrow, thanks for the links again.

Cheers.

Winfried

Hello

Did anyone on BF order a LoudBicycle car horn?

Loud Bicycle

I know someone who's interested, but I'd like some real user feedback.

Thank you.