Power drop problems (HELP)

[paidnfull]

35 minutes ago, Krisztián Arnold said:

So if I get a third meter, and read all three of the factors you mentioned, how do I measure the amperage? Because that is also needed inthe equasion. I do not want to be cantankerous or something, I only would like to learn.

I actually meant to say ac amperage, not voltage, I corrected it. 

 

However, you can calculate power(watts)  if you know the resistance of the load and the voltage put through it, because you can calculate the amperage with those two numbers. Either way, the load has to be resistive to get accurate readings.  If you're using a sub, the load is not resistive, so your results will not be accurate.  It's been proven that the typical "clamping" method is not accurate.  Close is some cases, but not exactly what you're looking for. 

You definitely won't get the answers you're looking for if you don't know the load you're putting on the amp.  Just pulling the ac amps and volt numbers will get a power number, but at what load?  That's what you have now, you know you're in the 800 watt range, but at 8 ohms?  4 ohms?  .5 ohms?  Who knows?  because you aren't measuring it.  You also will never really know what that amp is capable of with your two battery-bank, because you won't be able to keep the voltage stable long enough with the kind of load you're putting on it.  It's also nice to know the dc voltage and current going into the amp for multiple reasons, one being you'd get an idea on how much power is being wasted (efficiency), and a second being you'd know if you're setting the amp up to fail (low voltage input). 

I don't know of anyone reputable who does clamp tests with one battery and no other method of maintaining voltage.  Unless you're testing really small amplifiers, this would not yield very accurate results. 

[Krisztián Arnold]

4 minutes ago, paidnfull said:

I actually meant to say ac amperage, not voltage, I corrected it. 

 

However, you can calculate power(watts)  if you know the resistance of the load and the voltage put through it, because you can calculate the amperage with those two numbers. Either way, the load has to be resistive to get accurate readings.  If you're using a sub, the load is not resistive, so your results will not be accurate.  It's been proven that the typical "clamping" method is not accurate.  Close is some cases, but not exactly what you're looking for. 

You definitely won't get the answers you're looking for if you don't know the load you're putting on the amp.  You also will never really know what that amp is capable of with your two battery-bank, because you won't be able to keep the voltage stable long enough with the kind of load you're putting on it. 

I don't know of anyone reputable who does clamp tests with one battery and no other method of maintaining voltage.  Unless you're testing really small amplifiers, this would not yield very accurate results. 

So first thanks for your answers, they helped a lot.

I lost you a bit over the theme of what sould I be measuring than? Ohm load, Ac cureent, and ac voltage?

But as a quick reminder, I intend to use this whole suff with an alternator that provides enough energy to keep my setup at max. However when it is not on, then as a backup it would play instead (for example, when I am waiting for someone in a parkinglot, and do not want the engine running)

Realistically you are listening to music, which you do on subwoofers (partly ) so I do not understand why would it be bad if I measure my power using real life example, not a laboratory condition.

Yes, I am aware clamp test, is not a 100% accurate method, but that is what I have, and since it is used in so many cases I think it is the closest I can get, until I get my handheld oscilloscope and finally buy my AMM-1.

[paidnfull]

12 minutes ago, Krisztián Arnold said:

So first thanks for your answers, they helped a lot.

I lost you a bit over the theme of what sould I be measuring than? Ohm load, Ac cureent, and ac voltage?

But as a quick reminder, I intend to use this whole suff with an alternator that provides enough energy to keep my setup at max. However when it is not on, then as a backup it would play instead (for example, when I am waiting for someone in a parkinglot, and do not want the engine running)

Realistically you are listening to music, which you do on subwoofers (partly ) so I do not understand why would it be bad if I measure my power using real life example, not a laboratory condition.

Yes, I am aware clamp test, is not a 100% accurate method, but that is what I have, and since it is used in so many cases I think it is the closest I can get, until I get my handheld oscilloscope and finally buy my AMM-1.

AC current, ac voltage, and dc resistance would give you a pretty close reading on your power output at that given load.  I'm guessing you were somewhere north of 2 ohms during your initial testing, which actually means the amp showed pretty good, imo.  Especially considering, you were likely working with less than optimal dc voltage to begin with. 

 

Measuring dc amps and volts during this test would also give you some info on the efficiency of your amp (power in vs power out), and being able to see what voltage you're at during this test would tell you if you're kinda setting the amp up to fail.  If you're dropping to 10 volts, one- that's bad for your amp, two-that's not really fair to judge the amp on what it puts out at that voltage.  It's tested and rated at normal charging voltage, somewhere in the 13.3-14.4 ish range would be more fair, IMO. 

 

You can measure in a real life condition if you wish, but you must be realistic with how you interpret your results.  You initially thought your 800 watt numbers were not up to par, but if that amp is doing 800 watts into a load over 2 ohms, with subpar power to begin with, those numbers are very acceptable. 

 

 

[CleanSierra]

The amp is rated at 2000W RMS guys, look it up on Sonic Electronix, Jesus Christ guys did some research. The reason you are not seeing anywhere near 2K is because of impedance rise. Wired at 1 ohm nominal, you're likely rising to 2 ohms plus and hence you're 800W RMS result.

[Krisztián Arnold]

4 hours ago, CleanSierra said:

The amp is rated at 2000W RMS guys, look it up on Sonic Electronix, Jesus Christ guys did some research. The reason you are not seeing anywhere near 2K is because of impedance rise. Wired at 1 ohm nominal, you're likely rising to 2 ohms plus and hence you're 800W RMS result.

That is one of the most reasonable answers here. Thanks for puting it out there.

[Krisztián Arnold]

4 hours ago, paidnfull said:

AC current, ac voltage, and dc resistance would give you a pretty close reading on your power output at that given load.  I'm guessing you were somewhere north of 2 ohms during your initial testing, which actually means the amp showed pretty good, imo.  Especially considering, you were likely working with less than optimal dc voltage to begin with. 

 

Measuring dc amps and volts during this test would also give you some info on the efficiency of your amp (power in vs power out), and being able to see what voltage you're at during this test would tell you if you're kinda setting the amp up to fail.  If you're dropping to 10 volts, one- that's bad for your amp, two-that's not really fair to judge the amp on what it puts out at that voltage.  It's tested and rated at normal charging voltage, somewhere in the 13.3-14.4 ish range would be more fair, IMO. 

 

You can measure in a real life condition if you wish, but you must be realistic with how you interpret your results.  You initially thought your 800 watt numbers were not up to par, but if that amp is doing 800 watts into a load over 2 ohms, with subpar power to begin with, those numbers are very acceptable. 

 

 

Yes I accept everything you say except I do not think my voltage drops to 10 or somewhere around it. That is becouse AGM batteries are very sensitive voltage wise, and at most it would die out on me around 11.9 since from that point on it is concidered to be on 0% of charge level. 

Also your answers are incredibly helpful, but no one could come up with an answer to the question of that if I dropp my voltages so low, than howcome I can not reach even just a better number on burst after fully charging my batteries. 

Why should my resistence be DC if the amp is putting out ac amperages and ac voltages?

[CrackFactory]

So from my limited understanding you cannot measure the resistance accurately while power is applied. To calculate box rise measure the ac voltage and ac amperage from the amplifier. Divide the voltage measured by the amperage and you will have your resistance. 

When amplifiers are dyno'd they use a resistor not a speaker so its not subject to box rise and stays the same resistance throughout testing as opposed to a subwoofer that will raise and lower depnding on frequency.

So, since the amplifier is rated at 2000 watts @ 1 ohm with 14.4v and you're getting 800 watts @ 1 ohm+box rise with less than 12.8v seems very acceptable.

Dont take my word for it though. Learn ohms law and you can learn how to calculate almost anything with just two measurements.

[Krisztián Arnold]

6 hours ago, CrackFactory said:

So from my limited understanding you cannot measure the resistance accurately while power is applied. To calculate box rise measure the ac voltage and ac amperage from the amplifier. Divide the voltage measured by the amperage and you will have your resistance. 

When amplifiers are dyno'd they use a resistor not a speaker so its not subject to box rise and stays the same resistance throughout testing as opposed to a subwoofer that will raise and lower depnding on frequency.

So, since the amplifier is rated at 2000 watts @ 1 ohm with 14.4v and you're getting 800 watts @ 1 ohm+box rise with less than 12.8v seems very acceptable.

Dont take my word for it though. Learn ohms law and you can learn how to calculate almost anything with just two measurements.

Do you think, that 1.6 volts can actually make such a huge impact so it makes half the power? 

[Ron36]

These are specs on a DD M2 amp at 1ohm. At 12volts 1700rms and at 14volts 2400rms, Big difference. 

[Ron36]

Your amp is not even close to a DD amp in quality.