playing music while engine is off

[stickers]

I had the same question, araw araw 20-30 mins naka on ang radio, (engine off) while waiting sa parking. stock HU and stock front speakers + 2 additional 250w sa likod.

If it will lead sa premature discharge ng battery, yung naconsume bang charge ng battery naibabalik while the engine is on? I mean narerecharge ba sya?

[1D4LV]

I had the same question, araw araw 20-30 mins naka on ang radio, (engine off) while waiting sa parking. stock HU and stock front speakers + 2 additional 250w sa likod.

If it will lead sa premature discharge ng battery, yung naconsume bang charge ng battery naibabalik while the engine is on? I mean narerecharge ba sya?

if on stock, the power consumption is lower compared if you have a setup.
definitely, it will drain the battery, but it will be drained slower compared if you do have something that eats up the power.
i think kung 20-30 minutes lang, tapos babyahe ka ng isang oras, compensated na yung loss via alternator charging.

[[archie]]

yung akin 15mins pwede walang start. don't want to go over that kasi weak na crank sa 15mins. sq basic setup.

[jhnkvn]

Even if you have amplifiers which output a lot of power doesn't mean your speakers are receiving the exact rated watts everytime. It simply depends on how hard you push your system.

Your power consumption is lower than you think on a basic setup. In normal listening levels, your tweeters and midrange is throwing less than 20W. Bigger displacement drivers such as subwoofers and woofers generally need more watts so they're typically the power-hoggers.

Of course, this is only a generalization. I can have a 8" woofer sounding "big" and being energy efficient just by careful box construction and impedence curve tricks.

[[archie]]

^kanya kanya lang Yan. since your a numbers guy, maybe provide us with accurate numbers para alam namin limit on playing without starting. Let's say normal listening on a 160 to 200 watt amp. rms of 30watts per ch. running on 3 ch setup. 1sn battery. average time to discharge?

[jhnkvn]

^kanya kanya lang Yan. since your a numbers guy, maybe provide us with accurate numbers para alam namin limit on playing without starting. Let's say normal listening on a 160 to 200 watt amp. rms of 30watts per ch. running on 3 ch setup. 1sn battery. average time to discharge?

There's no accurate limit because there are too many variables in place. This is especially true if I were to crunch numbers.

In the speaker, there's the factor of speaker impedence. Take my midbass for example: It's nominal at 4ohms but at 69hz rises at 40ohms. And that's just one speaker! What about the others (midrange, tweeters, midbass). There's also a matter of crossovers. The reason why most installers throw out the Focal KRX3 crossovers is because it's poorly designed: there's an ohm load swing in the bass driver around 150hz as such when the system is pushed, the impedance drop is to around .8 ohms stereo causing some amplifiers to go into protection.

In the amplifier, there's the factor of efficiency. This is where amplifier topologies come into play wherein Class A/B amplifiers are less efficient than their Class D counterparts. Not to mention efficiency differs from amplifier to amplifier! Many would also be surprised that our amplifiers are more efficient when near their clipping output and during clipping! Your Class D amplifier might be 90% efficient near its RMS ratings but only 60% efficient at low-listening levels. Remember that this is efficiency... not output. Don't confuse the two.

And lastly, there's the condition of your battery which I won't go into detail because it's standard car maintenance 101.

Let's say your total system wattage eats around 200 watts for your 2-way component set and your 10" subwoofer per hour. 200W is what your amplifier will be throwing out to your speakers.. but let's say it's 70% efficient which is a between 50 and 90. Your amplifier will be demanding 200W/0.7 = 285.71W from your car battery. We then divide this by your usual battery voltage thus 285.71W / 13V = 22A

Because Motolite is stingy in their specification sheet, let's take a look at some "audiophile" batteries such as Stinger's 1SM battery because it's easier to get specifications: Stinger SPV35 (Stinger Electronics | Product Details). Note that there's different ampere/hour ratings depending on rate of discharge (that's another variable) but assuming the battery's fresh, that battery has a 1/2 hour rate of 43.75A or 21.9 ampere/hours, what this means is that your battery will provide 44 amperes of power for 30minutes before dropping down to <11V. So assuming system consumption is at a minimum (ex. no flashing of lights, etc.), your battery can provide power for approximately an hour before discharge.

I hope the math does not confuse anybody. Even I hate doing them

At the end of the day, it really differs by how much you're pushing your volume. Like I said, you're not actually doing 200W or 300W on an everyday basis. Scientifically, decibels is a bad measurement because speakers' sensitivity differs from driver to driver (ex. horns can be rated at 100dB versus your conventional 85dB efficient speaker) but since it's not like people know their power consumption on a rated basis, I still go for "volume". I simply hope people aren't deaf and that their 95dB isn't "normal conversational level" :D

[brainmafia_310]

Boss, whatever the allowable minutes that you can compute to run your very expensive sound set up using the battery, it is still not healthy, why? because as batteries discharge or even at constant volume setting but the sound produces is not constant (e.g. sudden bass and etc) the voltage drop correspondingly and as a reaction the system need to pull more ampere to keep it running. In turn and as a result, excessive heat will haunt every capacitor, resistor, transistor and etc. on the system.

so in short, if you really want to enjoy your music/sound set up i suggest keep the engine running otherwise, install a voltmeter and monitor it while you listen to your boom boom sounds - medyo hassle di ba?

[jhnkvn]

Boss, whatever the allowable minutes that you can compute to run your very expensive sound set up using the battery, it is still not healthy, why? because as batteries discharge or even at constant volume setting but the sound produces is not constant (e.g. sudden bass and etc) the voltage drop correspondingly and as a reaction the system need to pull more ampere to keep it running. In turn and as a result, excessive heat will haunt every capacitor, resistor, transistor and etc. on the system.

so in short, if you really want to enjoy your music/sound set up i suggest keep the engine running otherwise, install a voltmeter and monitor it while you listen to your boom boom sounds - medyo hassle di ba?

Actually pagnapapansin niyo sa mga shows, there are a lot of LnC (loud and clear) systems running off an array of batteries. The bad thing about batteries is that they're rated at <13V and as such, unregulated amplifiers have less output. For example, your Sound Magus amplifier might be running 70W at 13.8V but using the battery, you're doing something like 50W. Although uncommon, there are also regulated power supplies on amplifiers such as McIntosh, old-school Xtants, JL Audio amps, etc. which regulates their rail voltages.

Pero sasakit lang ulo ko if I delve into power supplies, a better idea is to read this link: Regulated vs Unregulated Power Supplies. If you're an electrical engineer, it might be a nice read. If not, you'd probably won't get it...

Well, there's more heat but.. most components (even cheaper ones) are built with pretty good heat tolerances. There was a time my Xtants were fry-an-egg hot (it's quite inefficient kasi) yun tipong hindi mo mahawakan ng 5seconds but it still kept on humming along. That's my old 1995 amplifiers which I used temporarily in 2011 btw.

But yes, it makes little sense na magyayabang ka ng sounds but with your engine off unless you're forced to due to circumstances (ex. nasa event ka sa SMX). Just by turning it on,you have your alternator helping supply the power your system needs for your car to output even MORE decibels. Seems like a no-brainer for me.

[[archie]]

^ahh ok... I'm no engineer, but understand numbers very well. Since you always deliver answers through numbers of xmax, slopes, etc. there would be a chart of some sort that you could manipulate to give average time before it discharge. I guess I'm wrong. on the other hand delivering constants is not far fetched.