Menu
Forum
General Car Audio
Subwoofers
Speakers
Amplifiers
Head Units
Car Audio Build Logs
Wiring, Electrical and Installation
Enclosure Design & Construction
Car Audio Classifieds
Home Audio
Off-topic Discussion
The Lounge
What's new
Search forums
Gallery
New media
New comments
Search media
Members
Registered members
Current visitors
Classifieds Member Feedback
SHOP
Shop Head Units
Shop Amplifiers
Shop Speakers
Shop Subwoofers
Shop eBay Car Audio
Log in / Register
Forum
Search
Search titles and first posts only
Search titles only
Search titles and first posts only
Search titles only
Log in / Join
What’s new
Search
Search titles and first posts only
Search titles only
Search titles and first posts only
Search titles only
General Car Audio
Subwoofers
Speakers
Amplifiers
Head Units
Car Audio Build Logs
Wiring, Electrical and Installation
Enclosure Design & Construction
Car Audio Classifieds
Home Audio
Off-topic Discussion
The Lounge
What's new
Search forums
Menu
Reply to thread
Forum
Car Audio Discussion
General Car Audio
My setup come see.
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Message
<blockquote data-quote="retrojordans" data-source="post: 7249877" data-attributes="member: 630134"><p>To calculate the current draw of an amplifier, multiply the number of channels by the RMS watts per channel (a 2 channel amp rated at 300 watts RMS per channel would be 600 watts). Double it to account for amplifier inefficiency (600 watts X 2 = 1200 watts), then divide by the average output Voltage of an alternator, 13.8 volts (1200 divided by 13.8 = 87 amps). Since the average music signal requires about 1/3rd of the average power in a test tone, divide by 3 (87 amps divided by 3 = 29 amps). The result is the amplifier's approximate average current draw.</p><p></p><p>A quick way to ballpark an amplifier's current draw is to divide the total fuse value of the amp by two. For amplifiers with multiple fuses, the rating of all fuses provided with the amp must be added together. This will likely produce a significantly higher estimate than using the proper formula. Although inaccurate, this will err on the side of safety.</p><p></p><p>Finally, compare the amplifier's approximate current draw to your vehicle's reserve current capacity to determine if the electrical system can support the amplifier.</p><p></p><p>If all those numbers are a bit much, here's a simpler way to think about it: an alternator capable of producing 65 amperes is usually adequate for systems up to 270 X 2 watts RMS. A compact car with a 35-amp alternator can accommodate around 150 X 2 watts of power, while a Sport Utility with a 145-amp alternator can handle a 600 X 2 watt system.</p><p></p><p><span style="color: red">If you want more power than your alternator can service, you will have to consider having your alternator rebuilt for higher output — or invest in a high-output aftermarket alternator. Installing a second battery won't help — that only allows you to play your stereo for long periods with the engine off. But, remember that any system playing at one-third volume is drawing considerably less current than the same system at three-quarter volume, and may not need a charging system upgrade if the volume levels are kept reasonable.</span></p><p></p><p><span style="color: red">If your system needs more current than the alternator can supply, it starts to grab current from the battery — not a good thing for your car or your music! Here are a couple of warning signs to look for:</span></p><p></p><p>* your headlights dim in time to the music when you crank it up loud at night;</p><p></p><p>* your bass sounds great when you first turn it on, but gets mushy and less powerful within a minute or so.</p><p></p><p>One easy, effective solution is installing a capacitor. Heavy-duty capacitors connect to the power cable (just before it reaches your amplifier) and act as a buffer zone between your amp and your car's electrical system. They store up a reservoir of power which can supply the amplifier's peak demands (like a kick drum beat) without having to pull current from the battery.</p></blockquote><p></p>
[QUOTE="retrojordans, post: 7249877, member: 630134"] To calculate the current draw of an amplifier, multiply the number of channels by the RMS watts per channel (a 2 channel amp rated at 300 watts RMS per channel would be 600 watts). Double it to account for amplifier inefficiency (600 watts X 2 = 1200 watts), then divide by the average output Voltage of an alternator, 13.8 volts (1200 divided by 13.8 = 87 amps). Since the average music signal requires about 1/3rd of the average power in a test tone, divide by 3 (87 amps divided by 3 = 29 amps). The result is the amplifier's approximate average current draw. A quick way to ballpark an amplifier's current draw is to divide the total fuse value of the amp by two. For amplifiers with multiple fuses, the rating of all fuses provided with the amp must be added together. This will likely produce a significantly higher estimate than using the proper formula. Although inaccurate, this will err on the side of safety. Finally, compare the amplifier's approximate current draw to your vehicle's reserve current capacity to determine if the electrical system can support the amplifier. If all those numbers are a bit much, here's a simpler way to think about it: an alternator capable of producing 65 amperes is usually adequate for systems up to 270 X 2 watts RMS. A compact car with a 35-amp alternator can accommodate around 150 X 2 watts of power, while a Sport Utility with a 145-amp alternator can handle a 600 X 2 watt system. [COLOR=red]If you want more power than your alternator can service, you will have to consider having your alternator rebuilt for higher output — or invest in a high-output aftermarket alternator. Installing a second battery won't help — that only allows you to play your stereo for long periods with the engine off. But, remember that any system playing at one-third volume is drawing considerably less current than the same system at three-quarter volume, and may not need a charging system upgrade if the volume levels are kept reasonable.[/COLOR] [COLOR=red]If your system needs more current than the alternator can supply, it starts to grab current from the battery — not a good thing for your car or your music! Here are a couple of warning signs to look for:[/COLOR] * your headlights dim in time to the music when you crank it up loud at night; * your bass sounds great when you first turn it on, but gets mushy and less powerful within a minute or so. One easy, effective solution is installing a capacitor. Heavy-duty capacitors connect to the power cable (just before it reaches your amplifier) and act as a buffer zone between your amp and your car's electrical system. They store up a reservoir of power which can supply the amplifier's peak demands (like a kick drum beat) without having to pull current from the battery. [/QUOTE]
Insert quotes…
Verification
Post reply
Forum
Car Audio Discussion
General Car Audio
My setup come see.
Top
Menu
What's new
Forum list
