Electronics and its effects on MPG

Weight is weight, whether by adding electronics or eating too much pizza. Weight will have some effect on mileage, but you can add a lot of electronics before you will notice any mileage hit from the weight.

Electronics also consumes electrical power, which despite what some people think, comes directly from your gas tank. Most normal electronics consume rather smallish amounts of electricity, so they are not a problem. If you add a bunch of plasma TVs or a 1000 Watt PA system it will start to cost you. Not a lot, but there will be a cost. One horsepower is equal to about 746 Watts. There are some conversion losses, so use 1 Hp to 1 KW as your guide.

Tom

 

:welcome: Welcome to PriusChat, allentu! I have no idea how much hit to mpg a 1Kw amp will cost, but read the Audio and Electronics threads for more info. One thing to keep in mind is that the Prius 12V battery is on the small side, sized for booting the computers. You may want to consider beefing up the 12V system if you intend to run big audio without the car in READY mode.

 

It depends - and some maths are involved. To produce 1000w on a 12 volt system means that you are drawing 80+ amps

If you hooked up a 1000 watt electric heater (or a class A amplifier) it would draw a continuous 1000w the whole time it was on - hp approx equal to 1000/750 or 1.3 hp

Audio amplifiers are a little different in that most are class B - this means that the power consumption is a factor of the music you play. On silent patches, the amp draws less than 1/10th of an amp.

If you listen to mainly classical then the average power used is around 2-5 watts. eg In the 1812 overture the only time power usage approaches anywhere near 1kw is when the cannons are fired.

Modern music tends to have a higher emphasis on bass - and bass notes require more energy to reproduce than the higher notes.

What is the mpg hit and does it matter?

Converting hp to mpg is a tad more difficult as a number of variables are involved. An excellent page is at Wayne Brown's Prius Simulator Site. Consider this summation about the effect rain has on mpg:

'... 2.84 kilowatt hours of energy drops the Prius' mileage from 47.69 to 40.77 MPG.'
​

So if 3kW drops the mpg by 7, then a 1kW heater will drop the mileage by around 2.


Hope this helps
Warwick

 

A 1,000 watt system?? Is it physically possible (assuming you are not 100% deaf) to listen to a 1,000 watt (and I mean a true 1,000 watts) system at 1,000 watts continuous output (which would mean the amp is probably drawing nearly 2,000 watts or excess of 160 amps) in any vehicle? The sound levels must easily be over 130 db. which would not only physically hurt but result in permanent and serious hearing loss.

What I am getting at is that most anyone who professes to have a true 1,000 watt system instantly swings my BS meter to full peg. I am sure they do exist, but the cost for a properly wired system is many thousands of dollars.

As an amateur radio operator who is familiar with amps up to 1,500 watts output, I would find it hard to imagine putting a true 1,000 watt system in a car. A 1,500 watt amp weighs nearly 100 lbs. and usually costs $3,000 and up. The heat put out by these amps is almost the same as blow dryer running full hot and you would be hard pressed to vent it properly in most vehicles.

Rick
#4 2006

 

My home audio system has a true 1000 W amp just for the subwoofers. Of course most of the time it's just idling along, but it's there when it's needed.

Tom

 

to answer the OP's question.
Now I only have a medium powered Sub configuration, but I have not noticed any loss at all in MPG. I only run 2 channels from my amp Bridged to a single 10 " Infinity Sub. My amp only runs 200 watts RMS per channel. The added weight at most is 20 pounds. If I didn't have my wife driving my Prius 3 times a week to school because she has the longer trip those days I would be averaging nothing but 60 MPG tanks.

 

The small amount of knowledge you have of the amplifiers in your transmitter that operates at RF frequencies has little to do with audio amplifiers.

As another poster pointed out, the circuit topology used by most audio amps only consumes a lot of power during low frequency peaks. SPLs that cause hearing damage only require a few tens of watts continuous but a few hundred watts peak.

I have "birth sheets" (test results) of the amps installed in my Prius, and even on just 12.5 volt power my subwoofer amp put out 346 watts continuous into 2 ohms with 0.7% THD and my four channel amp put out nearly 500 watts under the same conditions and at the same THD level. Both amps together probably weigh twenty pounds. The Class D subwoofer amp in my home theater is rated at 500 watts continuous/1500 watts peak and it's about the size of a college textbook (built into the subwoofer enclosure).

 

A 1000w amp isn't hard to come by. I just purchased one of these:

Hifonics BXi 1606D - 550 watts RMS x 1 chan. @ 4 Ohms / 1100 watts RMS x 1 chan. @ 2 Ohms / 1600 watts x 1 chan. @ 1 Ohm • Super D-Class Topography • Bass Remote • 95 dB - , Car Amplifiers, Mono Subwoofer Amps - Sonic Electronix

This is powering a :

Kicker 06VS10L74 ( VS10L7 4 ohms ) - Single 10" Solo-Baric L7 Loaded in a Vented Enclosure • RMS: 600 watts • Peak: 1200 watts • Impedance: 4 Ohms • Santoprene rubber surround - , Enclosed Subwoofer Systems, Ported Subwoofer Systems - Sonic Electroni

Since the sub is 4 ohms, the amp will only push 525w RMS at full power. This is way louder than i need, but if i were to get crazy, the amp will produce 1100w RMS at 2 ohms and a staggering 1600w RMS at 1ohm. This amp runs very cool considering it isn't being pushed too hard at 4 ohms. It also has a very low THD% (less than .1%) and the S/N ratio is 95db... all that basically means not only is it strong, but it delivers VERY clean bass.. Very nice setup. I would recommend this to anyone. And it comes with a remote volume controller which is invaluable when switching from one type of music to the next.