posted
Must your alternator put out as much current as your amplifiers draw in order for your electrical system to work properly?
example: a 200amp alternator and 2 amps with 80 amp fuses.
Or is it okay if your alternator puts out almost as much current as your amplifiers demand but youy have enough batteries so that their Ah excedes the ammout of current the amplifiers draw.
Example: a 200amp alternator and 6 batteries for a total of 480AH, running 2 Power 1100a2's that have fuse ratings of 100amps.
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posted
I wouldnt count on the batteries for any amperage. They might put out that much for a second or two. Once they cant supply that much their voltage drops and when that happens your amps power output goes down the crapper. In an ideal situation you would like to see your alternator(s) put out enough current to supply them. Plus the higher the voltage is the less current your amps need. Ex. 12v, they might draw 200 and at 16v they might only draw 130. Plus you have to remember that your car needs amperage to run on also.
------------------ 24 12's and a buttload of power!
Posts: 403 | From: Spokane Wa USA | Registered: Jun 1999
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posted
I hate to tell you this but you need to find out how big your stock alternator is and divide the number of amps in half so if it was a 60 amp alternator you'd get 30 amps which is WHAT THE CAR HAS TO HAVE then you find out how much current all of your amps draw, add a little extra and then buy an alternator that is a little bigger than what you actually need. Why you would have 6 batterys and only a 200 amp alternator I don't know. Every battery, cap, amp, neon tube, and anything else you add increases the load on the alternator. In order for a 12 volt battery to stay charged it must be supplied with 14 volts, I can't explain it but I know it's true. In order for you to get that 14 volts you must be making more power than all of the electical equiptment needs. If you're gonna play it loud and long with the engine off or idling for that matter the extra batterys(if they are isolated from the starting battery) will provide the current you will need, but you'll have to either turn the stereo off or down really low in order for the batterys to recharge. Those batterys and caps don't create energy, they just store it and if there isn't enough power left over from what all the electical components use, the battery's and caps won't recharge which is gonna leave you with a dead battery(s). But like Audiophyle said the amps don't draw that much current all the time, just when you crank it up. I'd still get a bigger alternator just so I'd know I had enough power to keep everything charger AND run the system at full volume if I wanted to.
posted
All a Capacitor does is store energy. It can't store what isn't there. A cap draws no amperage at all. All it does is supply energy that is stored quicker to the amplifiers.
------------------ Hittin' hard wherever you are......
Posts: 2542 | From: Moberly, MO USA | Registered: Jun 1999
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posted
Well yes and no........ The cap has to draw current to charge. Once it's drained, it presents more of a load on the charging system. Great for "burping" a system, but for a long period of time, opt for more batteries (longer term storage) and increased alternator output.
------------------ inno73@hotmail.com
Posts: 490 | From: Fort Frances, Ontario, Canada | Registered: May 1999
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Electrons take the path of least resistance. In the scenario described, with the vehicle running, the alternator will be called on to power the audio system, charge the batteries, and keep the car running period. Why? Because it has a higher voltage potential than the batteries. It makes in excess of 13.8 Volts, while the batteries have a nominal of 12.6 Volts. You can supplement this charge by storing it in capacitors for large current requirements on peaks. So, you can't cheat the laws of physics. You either have to store more charge in caps or increase the size of your alternator to cope with peak current demands. If you want to play rap music (like Bass Mecanik, Techmaster, etc.) that more closely resembles test tones, you're going to need a pretty beefy alternator to supply these continuous current demands.
With the vehicle off the batteries obviously supply the voltage to operate the system. In order for the batteries to be charged, you have to apply voltage somewhat greater than the nominal voltage of the battery (all cells combined is 12.6 volts)--like 13.4 or something. This allows a charge to flow in the opposite direction, thereby charging the battery.
Capacitors simply store "charge", whether it be positive or negative, in the role of supplementing your electrical system. They can also be quite beneficial in eliminating A/C ripple from your alternator. This becomes increasingly more important as you increase the size of the alternator--more charge means more ripple, or more NOISE to be more to the point. Also, by nature, a capacitor opposes changes in voltage which helps to get things more regulated.
Want to make your charging system the most efficient it can be? Then upgrade the return path!!! This is the single most overlooked area of a charging system. Ground the case of the alternator and the negative of all batteries to the frame of the car with the same size wire used for your positive runs. I usually ground the alternator and front battery(s) to the same point in the engine compartment, then ground the rear batteries to the same side of the frame in the rear.
BTW. . . your (6) batteries will be great for key off playtime though!
Snafu
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Posts: 144 | From: Phoenix, AZ | Registered: Oct 1999
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