my voltage on my power caps drops to 10-11 volts when im playing my music loud.. my bass amps stays on and the bass hits but the highs amp turns off. its suppose to be a 20 farrad cap. is it my alternator that is the problem? or is it the cap? or is the amp still taking too much power? or what is the problem? please help thanks

 

Try this: drive around (or, if parked, rev the engine to about 3K RPM) with all accessories turned off (AC, stereo, lights, etc) for about 15 minutes. This will ensure that your battery is fully charged. Use a multimeter to measure the voltage of your battery with your car running (still with everything turned off). It should be above 14 volts. If it isn't, you've got a BIG 3 problem (google or search this forum if you don't know the big 3) or maybe a bad battery. You should be using a good deep-cycle battery such as the Optima Yellow.

If it is above 14v at idle, then you are in good shape. The question that then remains is if your alternator can charge it at a faster rate than your stereo drains it. You did mean to say that you have a 2.0 farrad cap, not 20, correct? That, in addition to your amps, will put an additional strain on your battery. If you don't already have one, consider an aftermarket alternator. But again, whether or not your alternator can properly charge your battery or whether your battery can properly provide current for your demands will depend on the big 3.

The voltage dropping on your cap probably isn't a problem (or an indication that there is a voltage problem), as I am guessing that you are playing loud for some duration and then looking at the cap all while you are parked (ie, while your alternator is turning at a low rpm and your battery isn't fully charged).

As for your problem regarding the highs amp turning off, that may or may not be related to power. First, are you sure that the amp itself is turning off or is it just the sound from the highs that are ceasing? That could be a crossover protection feature (meaning you are overloading the speakers). If the amps are actually turning off then that could be a overheating protection feature.

First ensure your electrical system (big 3, batt, alt, cable runs) are up to snuff. If so, then consider heat and crossover protection features -- you may just need to change some settings or provide cooling.

Hope this helps.

 

I do agree somewhat with the above.^^^
I would say batt. voltage should be 12.5V, [everything off] 13.5V engine at idle, [everything else off] and no more then 14.5 engine at high RPM, [everything else off].
Voltage fluctuation when the audio system is cranked in not unusual but it should never drop below 11.5V at any time.

I also assume and hope you mean a 2.0 farad cap, [1 farad for every 500W of RMS power].

So a few things we need to know...
MM&Y of car.
Makes and models of equipment, at least the amps and subs.
How the amps are wired. power and ground wire gauge?
Where are the amps and cap grounded and how?
Type of main fuse/fuses used and their amperage.
Obviously the size of the cap.

Answer all the above as accurately as you can and we will be able to help a lot easier. 94

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DC_Civic08 &raquo;</TD></TR><TR><TD CLASS="quote">Use a multimeter to measure the voltage of your battery with your car running (still with everything turned off). It should be above 14 volts. If it isn't, you've got a BIG 3 problem </TD></TR></TABLE>
Or your alternator needs replaced.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DC_Civic08 &raquo;</TD></TR><TR><TD CLASS="quote">You should be using a good deep-cycle battery such as the Optima Yellow.</TD></TR></TABLE>
No need for a deep cycle battery. Unless you intend to deep-cycle the battery. A red top would work fine or any other low esr battery.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DC_Civic08 &raquo;</TD></TR><TR><TD CLASS="quote"> You did mean to say that you have a 2.0 farrad cap, not 20, correct? That, in addition to your amps, will put an additional strain on your battery. </TD></TR></TABLE>
Strain put on the electrical system by a cap is minimal compared to it benifits. At DC the current draw is equal to the leakage current. Under load the cap acts as a shock absorber, so any load put on the electrical system is the same as the load pulled by the amp. Nothing wrong with two big of a cap. IMO a bigger low ESR cap is better. These huge caps are usually put together by putting "smaller" caps in parallel which lowers the ESR even more.



Modified by nsxxtreme at 4:17 PM 3/24/2008