We get many e-mail's and telephone calls requesting information about high current alternators for custom high-power car audio systems. We even have a standard e-Mail response to such inquiries (CLICK HERE TO VIEW THIS) that generally describes our generators and their physical and electrical characteristics.
First and foremost, unless you have sufficient battery capacity to dedicate to the audio system, and use the correct type of battery, simply adding a high current alternator WILL NOT solve your power problems.
In our opinion, a good definition of "sufficient battery capacity" is when your fully charged battery (or batteries) can perfectly maintain your electrical system (all vehicle electrical components which share the battery, or batteries, with your stereo components), without any additional charging input, for at least 30 minutes (or longer -- based on how long you typically operate the audio system when the car is not traveling, more or less continuously, at highway speeds) -- without exhausting more than 50% of your battery's storage capacity.
Second, remember that automotive alternators do not produce their maximum output until engine speeds are well above idle -- typically 2,500-3,000 rpm on the average passenger vehicle. Further, they may produce very little (or even no) power at idle speeds. In stop and go traffic.
Third, you must know the peak, minimum, and average power requirements of your stereo system. Without this data you simply cannot properly determine how much alternator capacity that you require.
Basically, your alternator should produce AT LEAST 120% of your total continuous power requirement (150% is better) -- at the average engine speed of your vehicle while in use. If it does not, you will likely see your alternator fail prematurely.
For example, if your audio system demands an average of 100A, and if your basic vehicle electrical load is, say, 64A (typically 80% of your stock vehicle alternator's rated output), and you have installed a 200AH battery bank, you will need an alternator that can supply at least 300A.
assumes that you drive at average engine speeds sufficient to produce full power
from the alternator. However, average engine speed may not be sufficient to generate
full alternator power. In this case, an even larger alternator should be fitted
to properly supply the electrical system. In a low engine speed situation like this,
to supply your average electrical demand, it might be necessary to install a 400A
Fourth, remember that audio systems have high instantaneous power demands.
Alternators can not respond quickly enough to provide power for loud musical passages. A battery can respond quick enough to handle most fast moving audio loads and are key components in an electrical system supplying power to meet the requirements of high power audio systems.
However, and this is the fifth key fact, even when charging at a high rate, and at elevated engine speed, automotive electrical generating/supply systems (alternators and batteries), simply cannot respond to the quickest power demands of an audio system. They simply cannot provide additional current quickly enough to supply these requirements on their own. And, when engine speeds are lower, the typical automotive electrical generation equipment frequently cannot even come close provide the power needed. Therefore, for an ideal audio power system, very large capacitors, which can respond to ultra-short term system power demands even faster than a battery, are an absolute necessity. The size of your capacitor array is determined by your peak power demands.)
Since is it often very difficult, if not impossible to install a single large alternator, often the best automotive audio power supply solution is to "split" your electrical system -- dedicating one or more deep cycle batteries to supply just the high current demand components in your audio system -- charging that battery (or batteries) with a second high output alternator -- and leaving the "stock" electrical system (and engine starting battery) intact.
By doing this, ALL of the power produced by the secondary, high current, alternator is available to supply your audio system. This is exactly the sort of electrical system found on the typical emergency vehicle. AND, in most cases, it is by far the least expensive solution.
If the installation of a large, properly sized alternator, or a split electrical system (as described previously) is not possible consider installing a large battery bank, separate from the vehicle electrical system, to supply your audio system's power amps. Charge these batteries with a conventional battery charger when the vehicle is parked at home. When/if the batteries discharge to 50% (about 12.2 volts) turn off the amps until the batteries can be recharged.
While this means that your audio system might not be able to operate at all times, it is much better for your vehicle's alternator, battery, and delicate electrical components (computer chips, etc.) -- which can be seriously damaged by operation in vehicle system that operates with low system voltages.
ZENA's Modular Power Generators / Alternators Can Help
Read about choosing a high current alternator, then take your choice from:
Need even high charging current?
ZENA, Incorporated makes the only modular DC power generating units in the world. Multiple compact DC power generating units can be attached to a single driving engine source and be controlled and used together -- just as if they were a single giant alternator.
While this technology is normally used to producing large welding currents, ZENA's modular power generators can also be used, in synchronized groups, to efficiently produce very high, well regulated, battery charging currents (for example, from 300 to over 1,000 amps in 12 volt systems) -- serving as ultra high current alternator systems.
Unique Design Features Provide Unique Performance Benefits
The typical alternator is just not built like a ZENA DC power generator (a key reason why we make this distinction rather than referring to them simply as alternators). Therefore, if supplying a lot of power to a custom audio system and quickly charging batteries is important, a ZENA power generator is an ideal solution.
Unlike standard high-amp alternators most of which are designed to produce high currents for a relatively brief period, a ZENA power generator/alternator has been built to produce higher currents continuously --- an absolute necessity for welding, and also a great feature for big audio systems.
A number of features make ZENA power generators different from standard high current alternators:
As you might guess, none of these design/construction features have been selected because they are inexpensive. However, cutting costs on items that contribute to product reliability is not something that we do. In fact, our employees get more reward for finding parts with superior performance, reliability, or service life than they do for finding cheaper parts! (In our opinion better quality costs much less than a huge customer service department!)
These features do not, however, repeal any laws of physics, nor do they eliminate the necessity to follow good charging system design parameters. You should not scrimp on the selection of proper voltage regulation and/or system protection components for a given application -- nor should you ignore over temperature protection, manufacturer's recommendations for charging current/voltage, proper fusing, charge current limiting/monitoring during bulk charge, etc. These considerations are especially important if your are planing to charge a large battery bank (particularly a large AGM battery bank -- or battery banks made up of a more than three individual batteries wired in parallel) with a relatively small generating system. Such a system would be defined as one where battery capacity in amp-hours (AH) is more than twice the continuous charging capacity of a given alternator in amps. An example of this would be a 200A alternator being used to charge an 800AH battery bank.
Three Year Limited Warranty
Just try to find a high output alternator anywhere with a warranty -- or an overhaul/rebuilding policy like this!
ZENA™ is a trademark owned by ZENA, Inc. for its welding systems and related products.
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