Adding horn to float switch for bilge pump...?

[Rocky_Road]

Hey guys!

My new float switch is fused, and I was going to use the same size (5 amp) fuse that my bilge pump has.

However...I am thinking of adding a horn to the float switch circuit, and logic tells me that I need to up the fuse amperage to cover both the horn and the pump. There isn't anything on the horn to tell me it's draw, so please look at the pictures and make a guess of where I should go! My guess is around 7.5 anp (if there is such a thing)?

Happy boating!

 

[tractoman]

Re: Adding horn to float switch for bilge pump...?

I would leave it with the 5 amp fuse. That siren probably draws 1/4 amp.

 

[rbh]

Re: Adding horn to float switch for bilge pump...?

I have not done an DC amp draw test in a long time, but "I think" you hook the negative wire to the battery direct, then take the red/poss lead hook it to one leg on the multi meter and the other leg goes to the poss on the battery.
switch it to the amp draw and it should tell you what you want to know.
what did I miss??????

 

[Silvertip]

Re: Adding horn to float switch for bilge pump...?

Just make sure the meter is set to it's maximum current measurement capability. Starting too low can pop the meter or the internal fuse. Most hand held meters don't have a very high current measurement capability.

 

[Rocky_Road]

Re: Adding horn to float switch for bilge pump...?

Just make sure the meter is set to it's maximum current measurement capability. Starting too low can pop the meter or the internal fuse. Most hand held meters don't have a very high current measurement capability.

Thanks RBH and Silvertip.

I have a pretty expensive meter, that I have never actually used...I will try your suggestions!

Happy boating!

 

[Jeep Man]

Re: Adding horn to float switch for bilge pump...?

Rocky, I use those all the time in the alarm business. The draw is about 200ma. I have to question your pick, but to each his own. That is a piezo siren which produces a very high pitch shrill sound. Very hard on the ears. I will suggest another one from the same mfg. and the price is the same. It is about 2" round with an adjustable opening. Draw is the same. Hope this helps.

 

[Rocky_Road]

Re: Adding horn to float switch for bilge pump...?

It just registered a .19 on the 20 amp (auto range) setting.

This seems to indicate that I don't need to change from the original 5 amp fuse...correct?

Happy boating!

 

[Rocky_Road]

Re: Adding horn to float switch for bilge pump...?

Rocky, I use those all the time in the alarm business. The draw is about 200ma. I have to question your pick, but to each his own. That is a piezo siren which produces a very high pitch shrill sound. Very hard on the ears. I will suggest another one from the same mfg. and the price is the same. It is about 2" round with an adjustable opening. Draw is the same. Hope this helps.

You are right about the decibel level!

But I have never had to use my bilge pump, and I am trying to set the pump up with a float switch to avoid what happened to me launching the other day...I slid the boat off the trailer and entered the truck to leave the ramp when I realized that the plug was out. I pulled the boat back out and let the bilge drain for what seemed like forever! I am looking for the pump to auto engage in case this happens again, or I start taking on water while docked. In the case of the missing bilge plug, this siren would have got my attention before I made it to the truck even. If I spring a leak on the water and have to run the pump, I will cut one of the siren's wires to keep my sanity.

Is the .19 reading that I got match up to the 200ma that you gave me?

Happy boating!

 

[Jeep Man]

Re: Adding horn to float switch for bilge pump...?

You are right about the decibel level!

But I have never had to use my bilge pump, and I am trying to set the pump up with a float switch to avoid what happened to me launching the other day...I slid the boat off the trailer and entered the truck to leave the ramp when I realized that the plug was out. I pulled the boat back out and let the bilge drain for what seemed like forever! I am looking for the pump to auto engage in case this happens again, or I start taking on water while docked. In the case of the missing bilge plug, this siren would have got my attention before I made it to the truck even. If I spring a leak on the water and have to run the pump, I will cut one of the siren's wires to keep my sanity.

Is the .19 reading that I got match up to the 200ma that you gave me?

Happy boating!

Missed by .01........ about as close as DAMN is to swearing.

 

[Rocky_Road]

Re: Adding horn to float switch for bilge pump...?

Missed by .01........ about as close as DAMN is to swearing.

LOL!

Actually, it hit .20 several times, but I figured that it was at .19 for the most part!

I'm not going to worry about upping the fuse rating, and thank all of you for your help...!

Happy boating!

 

[madurodave]

Re: Adding horn to float switch for bilge pump...?

i did the same thing tonight. when bilge comes on, I will know about it. lol

 

[tractoman]

Re: Adding horn to float switch for bilge pump...?

Just add a diode on the power feed to the pump itself from the float switch. That way if the float switch is activating the pump you'll get the ear bleeding tone. (We use those piezos at my work too). But if you switch the pump on manually it will not backfeed to the piezo. This way no cutting wires if you need to manually run the pump.

 

[srimes]

Re: Adding horn to float switch for bilge pump...?

Great idea. And even if it floods and the float kicks it on you can switch it to manual to shut up the alarm.

 

[Rocky_Road]

Re: Adding horn to float switch for bilge pump...?

Just add a diode on the power feed to the pump itself from the float switch. That way if the float switch is activating the pump you'll get the ear bleeding tone. (We use those piezos at my work too). But if you switch the pump on manually it will not backfeed to the piezo. This way no cutting wires if you need to manually run the pump.

Now this gets my attention!

So...I will splice a diode into the float switch wire...slap on a little sealant...slip some heat shrink over this...and go in peace!

I will have this done before I head for the launch again. I have nightmares thinking about what I would have damaged if I hadn't thought of the plug before I had the truck parked 300 yards from the ramp.

Nice tip!

Happy boating!

 

[RickJ6956]

Re: Adding horn to float switch for bilge pump...?

Make sure you use a diode that's rated for the 5-amp load.

I believe I would add a float switch and dedicate it to the horn. That way you could manually turn it off independently so you wouldn't have to listen to it whenever the bilge float was raised.

BTW, .19 = 190 milliamps. 1,000 milliamps = 1 amp.

 

[scutly]

Re: Adding horn to float switch for bilge pump...?

My new float switch is fused

my switch is hardwired to the battery with NO fuse. is this wrong? i assumed blown fuse = sunk boat. no?

 

[Rocky_Road]

Re: Adding horn to float switch for bilge pump...?

Make sure you use a diode that's rated for the 5-amp load.

I believe I would add a float switch and dedicate it to the horn. That way you could manually turn it off independently so you wouldn't have to listen to it whenever the bilge float was raised.

BTW, .19 = 190 milliamps. 1,000 milliamps = 1 amp.

Good info.

I just got off of the phone with Radio Shack, and the guy I talked to didn't seem to follow what I was asking for...he said that he had diodes, but wasn't sure about the 5 amp rating! My next call will be to a 'real' electronics parts house, where I know the person on the other end of the phone wasn't frying french fries last month....

Happy boating!

 

[Rocky_Road]

Re: Adding horn to float switch for bilge pump...?

my switch is hardwired to the battery with NO fuse. is this wrong? i assumed blown fuse = sunk boat. no?

Rule offered the same switch either way...unfused, and with a fuse holder wired in from the factory.

I believe that anything that uses the boat battery should have fuse protection. The fuse is more to prevent a potential fire if a short occurs, than to protect the equipment. If the float switch is simply spliced into the bilge pump circuit, then the bilge pump fuse covers this...but if the switch runs directly to the battery (like mine will) then it is imperative that the wires are protected from a short. A boat that burned down to the water level, is less valuable than one that has just taken on water...!

Happy boating!

 

[NYBo]

Re: Adding horn to float switch for bilge pump...?

Rule offered the same switch either way...unfused, and with a fuse holder wired in from the factory.

I believe that anything that uses the boat battery should have fuse protection. The fuse is more to prevent a potential fire if a short occurs, than to protect the equipment. If the float switch is simply spliced into the bilge pump circuit, then the bilge pump fuse covers this...but if the switch runs directly to the battery (like mine will) then it is imperative that the wires are protected from a short. A boat that burned down to the water level, is less valuable than one that has just taken on water...!

Happy boating!

Well said. Definitely add a fuse.

 

[rjwoodrome]

Re: Adding horn to float switch for bilge pump...?

By all means fuse it. make sure you install your fuse as close to the power "supply" as practially possable. I have seen wiring harnesses smoke all the way back due to poor fuse location..