I looked at Swez's post about surge caps the other day, made me wonder if it's actually worth gettin one. I've measured it many times I don't lose even a tenth of a volt between the batt. and amp (under hood to trunk) under load it only drops down to about 13, sometimes 12 (car running of course @ 2000 rpm to simulate reg on the road driving).
It's supposed to be about 1600 rms, I'm not sure what the amp is actually running at right now though, it's at .5 ohms, which reminds me, I haven't been able to get a temp readout yet on the amp after driving from school yet, but how hot is to hot? It's gonna hurt if you grab the amp but it's not excessively hot I don't think, haven't had it go into thermal protection.
The only thing I've noticed is the lights dimming a little bit, which is kinda why I want to get a cap. That's where I'm not seeing the point where caps are useless. If it keeps your lights from dimming and keeping everything from being underpowered at larger bass hits, then it's doing it's job right? It supplies large amounts of current at once when needed, so when there's a gap in power it fills it, did they ever measure current when they were testing that? the cap could easily have just been making up for the voltage loss with more current.
I think of the cap as more of a safety measure to be sure you can see at night. But according to the document, they don't do their job.
Any ideas? I was kinda skippin around but main thing is if caps are worth it, 3 farads i'm lookin at.
Replies (3)
Junier on 10/23/2003 00:39:34
Back when I had my old system getting a cap barely helped my serious light dimming problems... So I sold the cap to a friend replace my battery with a Optima yellow top and all my light dimming stopped...
accusedmonk on 10/23/2003 06:27:37
I do have an Optima Redtop, rated at 980 CA, 800 CCA, I could be wrong about the cold cranking amps, don't remember that one all to hott.
How many watts was your system pulling, what was your cap rated?
It's probably not exact, but approximately 1 farad handles 1000 watts, 12-14 volts, somewhere around 100 amperes.
Swez on 10/23/2003 09:39:40
Monk,
A CAP is an expensive bandaid approach to a deep cut that really needs stiches.
In this case, more power for the amp at high power draw is more current/volts (watts) reserves. This comes from 3 main sources:
1. Adequate ALT output
2. Sufficient current storage capacity from the BAT (not a cap)
3. Large enough power wires to carry the current needed w/o taking too much (< 0.5) volts from the source to the load (BAT to AMP)
If any one of these is not up to snuff, something in the system will eventually fail. The cheapest 2 items you can change, are to upgrade the battery (current storage device) and the wires. (ALT/ BAT, BAT/GND & GND/ENG)
If that produces complete results... you are done. If not, then the hard one is next... upgrade the ALT.
The BAT mentioned, is adequate to the task, so using larger gage wires is your next option. Stock wiring is usually #10-8 wiring... except to the starter. That may be #6 or 4. Your other wires can be upgraded to #4 for more current handling ability.
Do you know the output current #'s on that ALT? It will vary with RPM and max output is usually near 2,000 RPM.
Swez
PS Some amps do get pretty warm when they are pushed hard and at 0.5 ohm loads, this heat can be considerable. But if the thermal protection circuits have not tripped, the amp is still operating in a heat range it can tolerate. MAY shorten the life of the transistors... but this depends on how hard you push the amp and how long it is under severe loads.
It would be wise to adjust the gain on your amp until the light dimming stops as you work on the next phase of your situation.
It's supposed to be about 1600 rms, I'm not sure what the amp is actually running at right now though, it's at .5 ohms, which reminds me, I haven't been able to get a temp readout yet on the amp after driving from school yet, but how hot is to hot? It's gonna hurt if you grab the amp but it's not excessively hot I don't think, haven't had it go into thermal protection.
The only thing I've noticed is the lights dimming a little bit, which is kinda why I want to get a cap. That's where I'm not seeing the point where caps are useless. If it keeps your lights from dimming and keeping everything from being underpowered at larger bass hits, then it's doing it's job right? It supplies large amounts of current at once when needed, so when there's a gap in power it fills it, did they ever measure current when they were testing that? the cap could easily have just been making up for the voltage loss with more current.
I think of the cap as more of a safety measure to be sure you can see at night. But according to the document, they don't do their job.
Any ideas? I was kinda skippin around but main thing is if caps are worth it, 3 farads i'm lookin at.
Replies (3)
Junier on 10/23/2003 00:39:34
Back when I had my old system getting a cap barely helped my serious light dimming problems... So I sold the cap to a friend replace my battery with a Optima yellow top and all my light dimming stopped...
accusedmonk on 10/23/2003 06:27:37
I do have an Optima Redtop, rated at 980 CA, 800 CCA, I could be wrong about the cold cranking amps, don't remember that one all to hott.
How many watts was your system pulling, what was your cap rated?
It's probably not exact, but approximately 1 farad handles 1000 watts, 12-14 volts, somewhere around 100 amperes.
Swez on 10/23/2003 09:39:40
Monk,
A CAP is an expensive bandaid approach to a deep cut that really needs stiches.
In this case, more power for the amp at high power draw is more current/volts (watts) reserves. This comes from 3 main sources:
1. Adequate ALT output
2. Sufficient current storage capacity from the BAT (not a cap)
3. Large enough power wires to carry the current needed w/o taking too much (< 0.5) volts from the source to the load (BAT to AMP)
If any one of these is not up to snuff, something in the system will eventually fail. The cheapest 2 items you can change, are to upgrade the battery (current storage device) and the wires. (ALT/ BAT, BAT/GND & GND/ENG)
If that produces complete results... you are done. If not, then the hard one is next... upgrade the ALT.
The BAT mentioned, is adequate to the task, so using larger gage wires is your next option. Stock wiring is usually #10-8 wiring... except to the starter. That may be #6 or 4. Your other wires can be upgraded to #4 for more current handling ability.
Do you know the output current #'s on that ALT? It will vary with RPM and max output is usually near 2,000 RPM.
Swez
PS Some amps do get pretty warm when they are pushed hard and at 0.5 ohm loads, this heat can be considerable. But if the thermal protection circuits have not tripped, the amp is still operating in a heat range it can tolerate. MAY shorten the life of the transistors... but this depends on how hard you push the amp and how long it is under severe loads.
It would be wise to adjust the gain on your amp until the light dimming stops as you work on the next phase of your situation.
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