AcuraFanatic

I plan on powering my 4-speakers with a 100W 4-channel (obviously) amplifier. My question is a capacitator needed for such a (relatively) low watt amp. I don't want battery drainage.

The car is a 1999 Honda Accord LX 4-cylinder with 27,200 miles on it, so it's a fairly new car/battery.

Thanks guys.

b00gers

no. because caps are generally used with sub amps. subs amps take huge surges of juice everytime the bass hits. that is when the cap comes into work.

since you are not using that as a sub amp, no.

97teg

It also depends on ig the amp is a regulated or non regulated design. Regulated means it makes about the sam amount of power even if the voltage drops and only draws a cretain amount even when making peak power. An unregulated amp usally tends to make more power but also draws more power to make it. If your amps are regulated its probably not that big of an issue to put a cap on it. Buy the amp first if you have problems with the electrical system lights dimming dead batt ect then you may need a cap.

fastball

If you are just running factory size speaker (6.5" front doors, 6x9" back deck) you won't need a cap. Caps are kind of overrated, IMO anyway. Cars made in the last couple of years have pretty high current alternators (at least 90 amps) to operate all the power windows and high current stuff as well as the fuel injection and ECU. Cars are tested under full load when designed.... that is A/C on recirc, full fan speed, all interior, trunk, and exterior lights on, cruise on, windows, door locks, and moonroof motors running, radio on full blast, wipers on high, you get the picture. If the alternator can pass the full load test, it will work fine on your amp. Those caps are really for competition, to show off, or for an older car with a weak alternator.

AcuraFanatic

Alright, thanks guys. $200 saved.

arch iceman

AcuraFanatic, your car should be fine without a cap.

Fastball, not neccesarily true about caps being overrated and for show.

You do have a valid point that most vehicles can support all onboard components and that is how they are tested.

I can show you an amp rated at 25 watts x 2, 50 watts total. The current draw on this amp is a continuous 50 amps. We measure this ourselves on a test bench with Precision Power technicians, its not a fuse rating or manufacturer rating. That is over half of the typical 90 amper altenators on most new vehicles.

In the past I think I read the ratings to operate a vehicle it takes about 15 amps for the air conditioning, and another 15 for the automatic transmission, Im not sure what the distributor and motor required, but assume 15 as well. Thats 45 amps without headlights or radio.

fastball

Arch, I'm not doubting your expertise one bit, but I work on car amps every day (not install, repair) and I've NEVER seen one that can draw more than one or two amps at idle, and when injected with a 10khz sine wave, mabe 10 amps at 14.4vdc constant at just below clipping. We use 4 ohm dummy load resistors which emulate speakers perfectly without a voice coil. We have very accurate 12 volt power supplies that have precise meters for voltage and current. In 5 years, I have never seen a car amp pull 50 amps continuous. Mabe -- MABE -- 20. Heck, the 32 volt B+ regulators will short out way before 50 amps, I don't care whose name is on the heat sink! Not to mention open all the emitter resistors in the channel and blow the ground even before the fuse blows. What do you use as loads, coat hangers?