aftermarket audio and leaf electrical system

[defiancecp]

So I'm a huge fan of high-quality audio. I haven't had a car with less than 1kw of amps in nearly two decades (crap, I'm old...). And no, I'm not talking about the thump-crap, I'm talking about real high quality across the range (way back I competed in USAC and went to finals twice; the last time I beat the champion in sound quality [he tore me up in install with some really cool a/v combination stuff that was just starting to emerge back then]).
ANYWAY...

So now I'm moving to a leaf, and trying to figure out what to do with it. I know I can't approach the same way I always have (massive power with immense headroom on all channels), since power consumption is a huge impact on range - but there's one thing I really don't know that's somewhat critical for consideration. At a very high-level perspective, I'd like to shoot for around 5-8% of range reduction in worst case as an upper bound.

However, what I'm missing is this - I know there's a 12v system in the car driving the accessories, and I know it gets a charge from the other systems in the vehicle. But how robust is the supply from main to 12v?




As an example, let's say I don't consider that at all. The car has an averate 100mile range on 24kwh. If you average a little under 35mph, that's going to take 3 hours to drain (I'm using longer drive times as worst case in my application, since that will require the audio to function for the longest amount of time). So using that for a baseline, it's consuming around 8kw per hour. So to reduce by 8%, that restricts me to 640w average power consumption, or at 12v, just under 55 amps.

Everything from the battery I can handle, but I'm guessing the primary system doesn't recharge the 12v (secondary? acc? whatever you want to call it) nearly fast enough to charge 55 amps more than it normally would, so that system would be under continuous drain if it were run at that level.


So the big question I'm building up to is, does anyone know how much power the leaf primary system is capable of supplying to the leaf secondary (12v) system?

I'm just guessing, probably nobody knows. But hey, can't hurt to ask if anyone has any idea, right?

 

[EVDRIVER]

1) I don't think you mean 1kw of amps as there is no such thing. The Leaf wil have a dc/dc converter and you will need to know the spec to see what you can use. The power in the car will be far cleaner than an ICE as there is no Ignition system and related noise. You could add secondary dc/dc converters at a very low cost. You need to calculate your draw in watts, 50A @ 12v is 600 watts and you could run the stereo at that rate for 40 hours. Adjust the math to calculate.

 

[defiancecp]

What do you mean there is no such thing? This is one of the amps in one of my vehicles now, and it's running 1 ohm mono (1200w rated), that's over 1kw right there.
http://www.edesignaudio.com/product_info.php?cPath=1_22&products_id=44

*edit* OH! I see what you're saying, amp being a measure of amperage, wattage being a measure of power. Sorry! to clarify, "amp" is also a common term for "amplifier", and there are plenty of 1kw amplifiers

Not the point though; I'm just wondering if anyone knows what the capacity of the built-in charging system (dc-dc converter) is.

 

[evnow]

So I'm a huge fan of high-quality audio. I haven't had a car with less than 1kw of amps in nearly two decades (crap, I'm old...).

What you mean is - you are a huge fan of high-quantity audio :twisted:

 

[LEAFer]

Take a look at a mod made to a Tesla. Required an extra (separately chargeable) battery.

http://www.teslamotorsclub.com/showthread.php/491-Blaujunk-Roadster-audio-NAV-options?p=36606&viewfull=1#post36606

http://www.teslamotorsclub.com/showthread.php/2399-Customized-Roadsters?p=35006&viewfull=1#post35006

 

[defiancecp]

So I'm a huge fan of high-quality audio. I haven't had a car with less than 1kw of amps in nearly two decades (crap, I'm old...).

What you mean is - you are a huge fan of high-quantity audio :twisted:

No, I mean what I said The issue is clipping and overhead as it relates to musical variations. Good music is not continuously full blast, it often varies from really quiet to extremely loud. The goal is to faithfully reproduce audio at such volume and signal/noise ratio that the quiet parts are clear and audible, the minor nuances during more complex portions are clear without being distorted by other aspects of the music, and when the music transitions to louder portions, it doesn't drive into clipping - EVER.

There are a number of methods of getting a system set up such that quiet portions can be reproduced faithfully and audibly and sudden transitions to very high volume don't drive clipping or distort the quieter nuances that are playing at the stame time... but extremely high power is one that makes it SOOOO easy The last car I competed with was capable of producing around 2800W of audio without the slightest bit of clipping. Only about 800w of that was on the subs. The thing is, though, due to the transient nature of (good) music, even running at max volume it probably averaged about 300-600 watts of actual power.

One of my best friends at the time was a huge bass-head, and so I had this argument with him about 3 trillion times

In the case of the leaf, obviously that option is out; I'll have to go for efficiency rather than simple overhead capacity... But more power is still better, so I just want to be sure I know where I can operate safely within the confines of the vehicle.

It's like a fun engineering puzzle to me

That Tesla link is very interesting.... I just hate to add a battery and the associated weight (for obvious reasons). My plans already involved a minimalist subwoofer in a small box with lightweight materials, removing the amps' stock heatsinks and machining a single lightweight heatsink, etc.). Especially since the leaf already *has* a 12v battery and electrical system, I'm much prefer to utilize it... As long as the charging system is up to the task.

Still, it is an option

 

[evnow]

There are a number of methods of getting a system set up such that quiet portions can be reproduced faithfully and audibly and sudden transitions to very high volume don't drive clipping or distort the quieter nuances that are playing at the stame time... but extremely high power is one that makes it SOOOO easy

Any music not reproduced at the same level as the source is distorted. Our ears have difference frequency responses at different dB levels. Very quite passages need to be heard at low dB. That ofcourse, is not possible in cars - so I don't bother

ps : The best music I've heard is using 3 watt SET amps :lol:

 

[defiancecp]

There are a number of methods of getting a system set up such that quiet portions can be reproduced faithfully and audibly and sudden transitions to very high volume don't drive clipping or distort the quieter nuances that are playing at the stame time... but extremely high power is one that makes it SOOOO easy

Any music not reproduced at the same level as the source is distorted. Our ears have difference frequency responses at different dB levels. Very quite passages need to be heard at low dB. That ofcourse, is not possible in cars - so I don't bother

ps : The best music I've heard is using 3 watt SET amps :lol:

Play a single chord on a guitar, measure inches from the strings and measure 20 feet away, and volume will vary by 30dB or more (note that the dB scale is logarithmic, and 10dB is equivelant of a subjective DOUBLING of volume, so 30db louder is EIGHT TIMES the subjective volume). Which is correct? Neither, it's the relationship of one component of the music to another that is meaningful. Measuring audio volume out of context is meaningless, and creating audio at a volume that represents the relative dynamics of the original source in a car is most certainly possible.

Not meaning to be overly contrary... But your statement equates to saying that no high-quality audio system would have a volume knob

 

[evnow]

Which is correct?

Are you talking about an audio recording-wise or artistically ?

Audio recording-wise what a microphone would have heard is how you want to hear it reproduced.

You mean, the music is not recorded using a simple stereo mic but is recorded using multiple microphones and remixed ? Then it doesn't matter .... the phase relations and a lot of other things is already lost.

 

[defiancecp]

As for your absolute volume adherence, remove all the volume knobs from all your audio reproduction equipment if you want, I think I'll keep mine thanks.

Meanwhile, since it can't be absolutely perfectly faithful reproduction (by your definition), would you be happy with a roadmaster tape player with busted speakers in your car? No? Ok, then you DO care about audio quality to some extent, even if it can't be "perfect". What extent you want to care about it is up to you. Obviously, my choice is different than yours.

I think this is one of those topics we'll just need to agree to disagree about.

 

[smkettner]

You will need to know the capacity to charge and maintain that 12v accessory battery or risk running it flat dead.
I would be curious what else that 12v battery powers or rather what all could become disabled if it becomes discharged.
I find far more enjoyment to just accept the sound system as is, and I wish you well on your project.

 

[johnr]

I doubt the Leaf's DC-DC converter is designed with enough margin to accommodate the additional power you want. But nobody except Nissan really knows the specs on it at this time. The good news is, the Leaf is essentially a giant rolling battery pack - so although it would directly reduce range you could run your amp at full power for many hours. Also since it's electric it's especially quiet so you have less noise to overpower your music. But you would probably have to source your own higher-power DC-DC converter to directly run your equipment from the main pack, if the connections are even accessible. And then you'd be messing with some pretty serious high voltage! Then again, since the Leaf has been designed to be very quiet you might find that with less background noise a lower-power amp will work better than expected.

 

[evnow]

As for your absolute volume adherence, remove all the volume knobs from all your audio reproduction equipment if you want, I think I'll keep mine thanks.

I'm not sure that would help to maintain the correct volume.

In anycase I was just commenting on your insistance that high volume is actually about quality reproduction.

Besides, I value my hearing.

 

[lne937s]

I would start by recommending a quality Class D amp to reduce the amount of energy used. I built an amp for home use and recommend UcD, but there are others (like the B&O ICE amps)- I am not sure which car amplifiers use those circuits.
However, it looks Pioneer uses ICE in their PRS-D series car amplifiers, as well as their Elite home recievers.
http://www.pioneerelectronics.com/PUSA/Products/CarAudioVideo/Amplifiers/ICEpower+Amplifier+Technology
http://www.pioneerelectronics.com/PUSA/Products/CarAudioVideo/Stage4/Amplifiers/PRS-D4200F

With a traditional A/B amplifier, half of the power consumption goes to heat- with Class-D, it less than half that amount. However, poorly made Class D sounds pretty bad, so be careful (ICE is used in some pretty expensive high-end gear). Most of the time, despite the amp ratings, you will only be using a small fraction of the power rating... stiffening caps will give you some headroom.

However, more benefit may come from reducing THD and improving s/n ratio- if you reduce noise, it will increase sound quality more than just adding headroom. Cars are pretty noisy places, but in a more quiet car, you will notice amplifier noise more.

Also look at more sensitive drivers. Many car drivers are pretty inefficient. Remember 90 db/w sensitive speakers require half the amplifier of 87db/w sensitive drivers (every 3db of additional volume requires a doubling of amplifier power).

Bottom line, the airspace of a car is 1/10th of that of a 12 ft X 12 ft room- to pressurize that amount of space to the same SPL (sound pressure level) should take 1/10th the power, all things else equal. If you are using relatively efficient speakers with a full 1kW of amplification in a car, it is enough to cause permanent hearing loss... be careful.

 

[defiancecp]

If you'd like to take this discussion to email is be happy to explain to you in detail how very high power applied at reasonable volumes with extreme damping and equalization techniques can bring phase and frequency response to a level of consistency, but at the cost of dramatic reductions in efficiency of the speaker system. And remember that 3db of volume is equivalent to a doubling of power... and 6-9db of reduction by equalizing and damping to compensate for peaks and valleys in a car environment is well within the bounds of expectation. That equates to a potential need of 8x power to compensate. Not to mention independently powered actively crossed over audio paths eCho with the same potential peak power requirements... and other techniques. So yea, power most certainly be used to increase audio quality. However, if you still want to argue your point of view, I'm sorry; I kinda tire of defending a perspective that's proven competitive in national level competition, so again, we will just have to agree to disagree.


Anyway.

I know that approach won't work in a leaf. That was the whole point of pointing it out, to say that it would be a different approach. I can make something work well on much less power than that, for example using passive crossovers where I usually use active, high efficiency components with very god innate frequency response, minimal damping, etc.etc.etc.... though it becomes quite a bit more expensive below a certain point. Thanks for the suggestions on the class d amps. I was already planning on them for low frequency stuff, but hadn't considered them for upper freq stuff. I'll look into the ice stuff.

But to make the best plan I still need to know the power consumption capabilities... I've sent a request to Nissan, but haven't heard back. I thought maybe they'd have released some technicAL docs to some of the dealers?

 

[lne937s]

If you'd like to take this discussion to email is be happy to explain to you in detail how very high power applied at reasonable volumes with extreme damping and equalization techniques can bring phase and frequency response to a level of consistency, but at the cost of dramatic reductions in efficiency of the speaker system. And remember that 3db of volume is equivalent to a doubling of power... and 6-9db of reduction by equalizing and damping to compensate for peaks and valleys in a car environment is well within the bounds of expectation. That equates to a potential need of 8x power to compensate. Not to mention independently powered actively crossed over audio paths eCho with the same potential peak power requirements... and other techniques. So yea, power most certainly be used to increase audio quality. However, if you still want to argue your point of view, I'm sorry; I kinda tire of defending a perspective that's proven competitive in national level competition, so again, we will just have to agree to disagree.


Anyway.

I know that approach won't work in a leaf. That was the whole point of pointing it out, to say that it would be a different approach. I can make something work well on much less power than that, for example using passive crossovers where I usually use active, high efficiency components with very god innate frequency response, minimal damping, etc.etc.etc.... though it becomes quite a bit more expensive below a certain point. Thanks for the suggestions on the class d amps. I was already planning on them for low frequency stuff, but hadn't considered them for upper freq stuff. I'll look into the ice stuff.

But to make the best plan I still need to know the power consumption capabilities... I've sent a request to Nissan, but haven't heard back. I thought maybe they'd have released some technicAL docs to some of the dealers?

I'm not saying that big wattage can not be useful in getting good sound quality, I'm just saying be careful. I built a 400w RMS/Channel amp (true RMS both channels driven at less than .03% THD 20Hz-20kHz- not those inflated ratings you see on most HT receivers or car audio) with and overbuilt 1450VA powersupply for very inefficient modified Magnepan speakers... But it was overkill, more than I needed and I would take a different path if trying to conserve energy.

Also, active crossovers tend to make the most out of amplifiers, passives add reactivity that makes amplifiers less stable. In my experience (Hi Fi home stereo), you are better from an amplifier stability standpoint to run more channels with an DSP-based active crossover than to bridge and run through cap, coil and resistor passive.

Unless you are running sine waves, I would not expect that Pioneer amp to be drawing much power compared to the resistive heater in the car. Having actually built a Class D Amplifier and having watched power consumption, I wouldn't expect that Pioneer amp advertised at 1200w (but is realistically 75 watts per channel at for 4 channels at 4 ohms) to consume more than 50-100 watts average in typical music operation. ICE amps are pretty good (not to be confused with some cheaper class D), like the ones used in this home theater receiver:
http://www.pioneerelectronics.com/PUSA/Products/HomeEntertainment/AV-Receivers/EliteReceivers/ci.SC-09TX.Kuro

 

[garygid]

The 2010 Prius can draw about 150 amps from the DC-to-DC converter, I think.
That provides for all 12v systems, including the headlights, turn signals, brake lights, etc.

I would expect the LEAF converter to be less amps, since the
LED headlights draw a lot less than the Prius non-LED headlights, I think.

The biggest non-linearity in the audio system is the speaker.
Moving lots of air requires lots of power.

The easiest way to use much less power is to use much smaller
speakers, ones that move just enough air for YOUR ears.

With proper headphones or earbuds, you can achieve wonderful
linearity and "depth". However, the other drivers around you
will lose the opportunity to listen to your choice of music.

No offense intended, just an idea to use a LOT less power
and still have a splendid power-efficient audio system.

 

[EVDRIVER]

The 2010 Prius can draw about 150 amps from the DC-to-DC converter, I think.
That provides for all 12v systems, including the headlights, turn signals, brake lights, etc.

I would expect the LEAF converter to be less amps, since the
LED headlights draw a lot less than the Prius non-LED headlights, I think.

The biggest non-linearity in the audio system is the speaker.
Moving lots of air requires lots of power.

The easiest way to use much less power is to use much smaller
speakers, ones that move just enough air for YOUR ears.

With proper headphones or earbuds, you can achieve wonderful
linearity and "depth". However, the other drivers around you
will lose the opportunity to listen to your choice of music.

No offense intended, just an idea to use a LOT less power
and still have a splendid power-efficient audio system.

Headlights are minimal the Leaf will be 100A at least.

I have worked with the B&O modules they are nice for what they are, class d is just not the same quality for high freq..

 

[defiancecp]

The only people listening to my music will be those in my car. Headphones are a great idea (especially considering they'd insulate the listener from road noise and such as well!) But I'm pretty sure headphones in a vehicle are illegal, so that option is out

As for the repeated calls for me to use less power, that's the point in this car and the whole point of this thread - but for those of you saying (without the slightest bit of firsthand knowlege) that I need to listed to lower volumes: If you wish for me to explain more details about how power and audio quality relate even at moderate volumes, email me or let's take it to an audio forum somewhere. Otherwise, let's focus on the leaf rather than advising me further on my (and a number of wold-class competitors I've beaten, for that matter) supposedly misguided audio perspectives.

Anyway - to respond to those who've discussed the power supply question (Thank you!!!), if it'll do 100A, I'm probably OK; at 150 I'm in great shape. Given the transient nature of music, if my setup has a peak draw of 50A, it'll draw on average a LOT less than that, maybe 20A. So I might have to be considerate of the situation if I'm running all accessories (a/c or head plus lights plus music), but it certainly shouldn't put any unmanageable strain if that's the case.

 

[garygid]

Draw 20 or 50 amps, but when the car needs "max" power (headlights,
brake lights, turn signals, Nav, etc. ???) will there be sufficient left over
for your "extra draw"?

Or, will it "blow" the DC-to-DC converter, or peraps just its fuse.