Amp draw on a marine AM/FM stereo/Ipod player?

[centerline]

I cant seem to find a decent answer on the power consumption for my stereo....
does anyone know what the approximate power draw on something like this would be? a basic marine version of a car stereo/ipod player...

I called two different stereo stores this morning to get an answer from them.... one store told me that, "its around 15 to 18 amps"....
the other store told me, after he asked me what it was in, "well we dont do sailboats here, we only install in cars and sometimes boats with motors, so no one here knows"....

I didnt let either "answer" go without a colorful comment, because as much as I dont know what the correct answer is, or about car/boat stereos, I am absolutely certain I knew more than they did and that that neither employee was really qualified to be installing stereos... or selling for that matter.
sometimes it better to just tell the truth and say "I dont know" rather than trying to blow a smoke screen to hide your ignorance of the subject:cry:....

but then I called best buy and got a somewhat better answer... they gave me a tech support number for pioneer.... no answer today.

I suppose its expecting a bit too much from the sunday stereo installers to be supplied with the handbook with the answers to all the top secret information so early in their career

 

[Team118]

Well, amps = watts/volts

You know volts, I assume 12

Most stereos would push out maybe 160 watts...

I'm not sure if this an accurate way to figure it though.

 

[jackhartjr]

Re: amp draw on a marine AM/FM stereo/Ipod player??

Call Crutchfields, they will probably know!
I think it is www.crutchfields.com
Jack

 

[Ralph Johnstone]

Re: amp draw on a marine AM/FM stereo/Ipod player??

I have noticed that my Xantrex Link 10 battery monitor shows about 1.5 A when only the Kenwood CD player is on. Doesn't matter what the Kenwood is doing either, MP3, IPOD, CD, AM, or FM, the amp draw is about the same.

Now mind you, no big woofers or tweeters here .................. that may consume more power.

 

[Stu Jackson]

Re: amp draw on a marine AM/FM stereo/Ipod player??

Ralph's right, all the rest is conjecture.

Our Link measures the stereo we have (Sony car radio with CD changer PLUS a powered subwoofer) at around 1.0A at reasonable volume.

If you're doing it for an energy budget, then the power draw at 1.0 to 1.5 A is more than adequate since the only other variable is the amount of hours you use it, right?

 

[WayneH]

Re: amp draw on a marine AM/FM stereo/Ipod player??

We don't boombox or even rock out the fish so when the stereo is playing it's using about an amp. But I can watch the ammeter jiggle while Eric Stone sings. ;D

 

[centerline]

Ralph's right, all the rest is conjecture.

Our Link measures the stereo we have (Sony car radio with CD changer PLUS a powered subwoofer) at around 1.0A at reasonable volume.

If you're doing it for an energy budget, then the power draw at 1.0 to 1.5 A is more than adequate since the only other variable is the amount of hours you use it, right?

thank you Stu and Ralph...
yes, I am trying to figure my daily 24hr power consumption to size my solar panel upgrade....
and no amps or sub-woofers here.... ALTHOUGH, when out at the lake i have thought about how nice it would be to have a couple of them loud-ass booming speakers mounted up in my spreaders so i could compete with the noise that they call music, that is coming from the many wakeboard boats around the lake..... or at least drown it out with something I like

 

[kloudie1]

Re: amp draw on a marine AM/FM stereo/Ipod player??

You can buy an ammeter at Harbor Freight for $3.99 which will measure the power draw of the stereo with enough accuracy to satisfy the kind of number that you are looking for. All of the stereo amps/receivers are a little different so measure yours to see what it needs to run the way you run it.. MaineSail posted some stuff a couple of years ago that showed the power being consumed by the rig he was playing.. It is an easy measurement.. Good Luck.. !-2 amperes is in the ballpark.

 

[Ron20324]

why don't you post the model number? Did you try the manufacture's web site?

 

[Anonymous 121765]

I just read thru this thread and one thing that puzzled me was no mention of reading the specs in the manuals that came with the units. Your AMP info will be listed there.

If having no manuals, you can find them online. Download them and save to your computer.

CR

 

[chp]

I have a Dual marine stereo. The manual has no info on watts or amps required. Nothing even on the info plate on the stereo itself. It does however have a 10 amp fuse built into the unit at the back. I only run the 2 speakers it came with, however I'm sure if I would use 2 more and the subwoofer the stereo can support the draw would go up significantly. I was kind of ticked off that there is no other info about the power draw. I just ran the wiring to the size of the 10 amp fuse.

 

[philwsailz]

Look at the fuse on the unit. Divide by two and you will have a decent guess as to average to heavy draw. Typical use for one of us, an "amp-and-change" as Stu points out, up to sometimes 5 amps if you are ashore getting supplies and you leave the teenagers on the boat....

Power used is dependent upon many variables, including quantity of speakers, impedance of speakers, music type, listening volume, and tone control settings. It also varies by brand.

Team118 proposed backing up from power specs and that is an okay way except no radio puts out the power he mentions. The power spec he used is PEAK power. Marketing number...... When Lightning Strikes. The real sinusoidal RMS power a 12v head unit can provide is only about 12 watts x 4, all speaker channels driven at 4-ohms. Many electronics firms put a peak power number on their carton usually suggesting somewhere between 2 and 6 times real output. It's not fair, but it's true that they do.

In summary, and to repeat, for a worst-case load in order to budget total electrical draw, consider the fuse supplied with the radio you intend to use, and budget roughly half the fuse value for your probable average current draw. Run the radio quiet and you will use less. Just know "sundowners" often cause radio current draws to go up. They also make you more popular and better looking but that's another topic...

 

[All U Get]

Run the radio quiet and you will use less. Just know "sundowners" often cause radio current draws to go up. They also make you more popular and better looking but that's another topic...

How many amps or "sundowners" do you think it would take? I'll write it down for the other Mainers.

All U Get

 

[WayneH]

How many amps or "sundowners" do you think it would take? I'll write it down for the other Mainers.

All U Get

The other problem with "sundowners" is they make you think you can take a guy with a stick and a radio to call more people with sticks and radios. :naughty:

 

[philwsailz]

To put science behind it and refute those bogus claims on the cartons of most radios, consider this.

First off, there is Ohm's law where we have
P=Power in Watts
V=Volts
I=current in Amperes
R=resistance,
(actually a misnomer when taling about speakers since thay are AC devices, hence R=Impedance to keep it in the vernacular of the commom man, but impedance =Z to be totally correct. Impedance varies with frequency)

These equations are true:
P=IV
V=IR

To answer the question or refute the myth of peak power lets use math to come up with an expression which isolates Power, Voltage, and Resistance:
Lets express V=IR this way: I=V/R and then substitute it in the first eqaution P=IV. The result is
P=V^2/R

Mobile speakers are normally a nominal 4 ohms, (usually 3.6-ohms or so), so lets use a value of 4 for R. An electrical system in charging with a motor running will have upwards of 14 volts, but we are sailors right. Lets assume a value of V of 12, since of course we call these 12-volt systems, right? Using this math, and assuming 100% efficiency, (most class AB electronics devices are only about 40% eficient, but hey we are in fantasy world) we can see that we get this.

P=12^2/4 =36 watts

Since a mobile stereo has 4 speakers, the math, assuming 100% efficiency says the total power of the radio, if 100% of the power going in comes out the speakers, is going to be only 144 watts. Not the 200 or more often claimed. When we plug in the efficiency factor that is common, we will see that the radio is good for about 60 watts total power, or 15 watts for each speaker. This is the defacto pure science and cannot be argued. Unless we look at it another way:
Suppose the radio runs consistently just under the current draw required to blow the radio fuse. Most radios are fused ast 10 amps. Back to the equations, and using P=IV, we can see that for a current of 10 amps and a voltage of 12 volts, there is ONLY 120 Watts of power available on the power wiring to do everything in the radio... Any more and you blow the fuse...


Sorry for the tangent, but I share these things in order to do my small part in educating folks to look deeper on the specs to determine the real power poutput of a given device. When considering purchase, and using power output as a decision criteria, one cannot use the BS numbers provided on the carton. They are not based on any reality I know of... Know that you can dig and often find a group of specs under a rataings guideline known as CEA 2006. This ratings standard was developed by an industry group to provide a level playing field for comparison of power output numbers. Know you will often find devices with both a bold PEAK power in big bold letters, and then find the CEA2006 numbers somewhere else. This is not a perfect scenario, as you the consumer have to dig to find the truth, but it is at least better than shoping blind with the bogus peak power numbers....


BTW, Centerline, the fact that you called two mobile audio shops and got the answers you did makes me laugh, and cry. The mobile electronics industry has lost its core competency. Does it matter that a stereo is going in a sailboat? Really????? It is sad that you can't find real audio experts anymore.... I deal with it every day.....

 

[navigator97]

Phl, the entire 12V DC (more likely 12.6V DC) does NOT reach the speakers. The voltage level at the speakers is significantly less than 12V - it is closer to 1V or so of AC audio signal. All in all the DC current draw is more likely to be about 0.5A DC form the power source. IMHO.

 

[philwsailz]

Phl, the entire 12V DC (more likely 12.6V DC) does NOT reach the speakers. The voltage level at the speakers is significantly less than 12V - it is closer to 1V or so of AC audio signal. All in all the DC current draw is more likely to be about 0.5A DC form the power source. IMHO.

The typical car audio/mobile audio radio uses the supply voltage to drive the rails of the output device. They are very inefficient... Desitpe this inefficiency, your numbers are low, unless you are only talking abot using the radio with a volume setting of 2 or 3 out of 50....

The truth is that the AC voltage measured between the speaker's + lead and the speakers - lead is usually going to be between 6.5 and 7 volts peak at peak output. The average RMS value is going to be different, dependent upon source material and tone settings. The average current going to each speaker will be about an amp, again dependent upon source material and tone settings.


Know my comments immediately above are very general and are there to refute common misconceptions of peak power, through use of very basic math and a couple of assumptions. A teenager in a car using stereo X will use way different amounts of juice compared to one of us in a sailboat using the same stereo X. To that end, ther is no precise answer to the question. But, to suggest that only a half-amp of power is used by the radio is going to often be an understatement.

 

[Dave602]

I just installed a Fusion stereo with the IPOD insert. When I checked it cranking it was less than 2amps on my battery monitor I believe. I can give you a firm figure next time I'm down there if you like. I was actually surprised.

 

[centerline]

To put science behind it and refute those bogus claims on the cartons of most radios, consider this.

First off, there is Ohm's law where we have
P=Power in Watts
V=Volts
I=current in Amperes
R=resistance,
(actually a misnomer when taling about speakers since thay are AC devices, hence R=Impedance to keep it in the vernacular of the commom man, but impedance =Z to be totally correct. Impedance varies with frequency)

These equations are true:
P=IV
V=IR

To answer the question or refute the myth of peak power lets use math to come up with an expression which isolates Power, Voltage, and Resistance:
Lets express V=IR this way: I=V/R and then substitute it in the first eqaution P=IV. The result is
P=V^2/R

Mobile speakers are normally a nominal 4 ohms, (usually 3.6-ohms or so), so lets use a value of 4 for R. An electrical system in charging with a motor running will have upwards of 14 volts, but we are sailors right. Lets assume a value of V of 12, since of course we call these 12-volt systems, right? Using this math, and assuming 100% efficiency, (most class AB electronics devices are only about 40% eficient, but hey we are in fantasy world) we can see that we get this.

P=12^2/4 =36 watts

Since a mobile stereo has 4 speakers, the math, assuming 100% efficiency says the total power of the radio, if 100% of the power going in comes out the speakers, is going to be only 144 watts. Not the 200 or more often claimed. When we plug in the efficiency factor that is common, we will see that the radio is good for about 60 watts total power, or 15 watts for each speaker. This is the defacto pure science and cannot be argued. Unless we look at it another way:
Suppose the radio runs consistently just under the current draw required to blow the radio fuse. Most radios are fused ast 10 amps. Back to the equations, and using P=IV, we can see that for a current of 10 amps and a voltage of 12 volts, there is ONLY 120 Watts of power available on the power wiring to do everything in the radio... Any more and you blow the fuse...


Sorry for the tangent, but I share these things in order to do my small part in educating folks to look deeper on the specs to determine the real power poutput of a given device. When considering purchase, and using power output as a decision criteria, one cannot use the BS numbers provided on the carton. They are not based on any reality I know of... Know that you can dig and often find a group of specs under a rataings guideline known as CEA 2006. This ratings standard was developed by an industry group to provide a level playing field for comparison of power output numbers. Know you will often find devices with both a bold PEAK power in big bold letters, and then find the CEA2006 numbers somewhere else. This is not a perfect scenario, as you the consumer have to dig to find the truth, but it is at least better than shoping blind with the bogus peak power numbers....


BTW, Centerline, the fact that you called two mobile audio shops and got the answers you did makes me laugh, and cry. The mobile electronics industry has lost its core competency. Does it matter that a stereo is going in a sailboat? Really????? It is sad that you can't find real audio experts anymore.... I deal with it every day.....

Phil, this is all great stuff! thank you... I am going to call the manufacture tech support today. I will explain to them why i need some specific numbers and see what kind of answer i get from them.....

I understand it is going to be a variable number due to the volume level, or how hard the speakers have to work. we have 4 speakers... one in the v-berth, 1 on the bulkhead above the dinette, and 2 flushmount outdoor speakers in the cabin/cockpit bulkhead facing outward, and they dont work very hard.
someone got the installation perfectly balanced with good speakers because we can play the music very softly, yet get a full, rich sound without it being in the way of normal conversation. and this is very unusual for me because my hearing is not too good anymore... too many sounds usually get all garbled and i cant hear nothing but noise, but this is all so perfect.
we dont play our music loud enough for other boaters to hear, no matter if we're at the dock or on the hook. although its all decent popular music for folks of our age group, we think its just as rude for us to force our music on to the neighbors as it is for them to make us listen to their noise....

 

[Bluesharp]

I made some measurements last year and this is what I got:

• Stereo on standby : 0.85A
• Stereo with IPod on: 1.24A
• Stereo on using tuner: 1.00A
• Stereo on using CD Player: 1.30A

Hope this helps!