OK heres the deal....no laughing guys... me and my buddies have a old chevy chevette that we have been trying to fix up for show...This year we don't have the time to really get into body work so we figured a quick audio system would work.... Heres the set up
HU- Pioneer
45 by 4 cd player don't know the model but it was sitting arounhd and did the job better than the AM radio ripped the single speaker out o the dash and put two tweeters in front corner for front and SONY 6X9s boxed in back of front seats
AMP- DEI 1100 at 1 ohm class D amp
SUBS- Kicker 2 dual 2ohm Kicker CompVrs
WIRE 4 gauge power dual 6 gauge grounds
Stifling Cap SPL 1.2 farad
Here is the fun part when wired the subs to 4ohm the voltage dropped to 11 volts during hard bass notes but the subs would not play as loud as expected and hinted distortion... I knew that at this rate the subs where not getting there RMS potential anyways so I wired the subs Parralel real quick to see the results they rated at .8 ohms for some reason this way but the math says 1 ohm thats not the problem though....The bass hit perfect this time no hint of distortion but slight clipping at high volume...
The problem....the voltage dropped down to 9 and under during a hard hit and the effects where very noticable...includeing amp going unstable and lots of heat.
I need a solution... first on the list is adding ground and power wires for battery and alt.
but not shure the old motor can hold a higher output alt was thinking mabe a second battery would help...i've read about optima and batcap but can't find anyone to tell me if they are all hipe...
Replies (3)
Swez on 07/31/2003 18:21:38
Yep, classic sign of electrical system overload. When the Car is running, the ALT can only put out so much current before it calls on the battery to take up the slack for more current. As current demand increases, voltage drop will follow.
Most amps will not do well with less that 10 volts and can become unstable. In fact, this much power draw can actually shut off the engine through power starvation.
My guess, this old Chevette has maybe a 65A ALT and 450 CCA rated battery. This amp probably draws more than 75 amps at full power. If you want to avaoid buring out the present ALT, it may be swapped with a larger current version or tweaked for more output by a good ALT rebuilding shop.
Yes, a larger battery (750 CCA rating or higher will help, as will larger gage wires to ALT/BAT and BAT/GND... but the basic problem is still there... inadequate ALT power.
Call around and see if you can get a higher Ampere rated ALT in that location. I would suggest a minimum of 85A and if possible, make it 100A.
Swez
_Robbob_ on 07/31/2003 20:41:07
The high output alt is a likely necesity i just hope that the original four banger can handle any extra stress the thing doesn't even have power stearing ...
Some body told me that most Gm alt are compatible with other GM vehicles ...makes me wonder if i get a really nice one for the upcoming show maybe i can swap it later with my truck...lol that would be nice...
Thanks again man
P.S. Anyone tell me if Batcaps are all hipe and no go???
http://www.batcap.net/home.htm
They ****claim**** that their smallest battery is worthy of 100 Farads but last time i checked...well i haven't cuz i don't know how to...How do you do math to figure Farads the only time i ever heard of them is with stiffling capacitors not batteries?
Swez on 07/31/2003 21:13:26
Truth is an 800 CCA rated battery is same power storage equivelent of 2,000,000 Farads of storage.
Also, you are correct that GM has a large grouping of ALTs that may fit in that mounting harness and have larger power output than stock. May be a bit harder to retrofit a larger GM alt into that bracket assy... but a cleaver fabrication job can make this work if you have the proper wiring harness for internal regulator etc.
Rebuilds are a lot cheaper and usually have lifetime warranties too. I just bought a 108A for Mom's Buick LeSabre and it costs $66.00 after core charge returned. Lifetime warrantee too. A 10 minute job!
Also, my 120A GM just died and I sent it back to where I bought it 4 years ago. Only had to pay insurance and shipping. It was a rebuilt and died while I was on a road trip... but found a local parts store that had what I needed and replace same ... right in the parking lot in like 15 mins.
It is same shell and casing as the 108A version, but beefier guts. You may get lucky too or have to fabricate a bracket to install a larger ALT in the same location.
Good luck,
Swez
HU- Pioneer
45 by 4 cd player don't know the model but it was sitting arounhd and did the job better than the AM radio ripped the single speaker out o the dash and put two tweeters in front corner for front and SONY 6X9s boxed in back of front seats
AMP- DEI 1100 at 1 ohm class D amp
SUBS- Kicker 2 dual 2ohm Kicker CompVrs
WIRE 4 gauge power dual 6 gauge grounds
Stifling Cap SPL 1.2 farad
Here is the fun part when wired the subs to 4ohm the voltage dropped to 11 volts during hard bass notes but the subs would not play as loud as expected and hinted distortion... I knew that at this rate the subs where not getting there RMS potential anyways so I wired the subs Parralel real quick to see the results they rated at .8 ohms for some reason this way but the math says 1 ohm thats not the problem though....The bass hit perfect this time no hint of distortion but slight clipping at high volume...
The problem....the voltage dropped down to 9 and under during a hard hit and the effects where very noticable...includeing amp going unstable and lots of heat.
I need a solution... first on the list is adding ground and power wires for battery and alt.
but not shure the old motor can hold a higher output alt was thinking mabe a second battery would help...i've read about optima and batcap but can't find anyone to tell me if they are all hipe...
Replies (3)
Swez on 07/31/2003 18:21:38
Yep, classic sign of electrical system overload. When the Car is running, the ALT can only put out so much current before it calls on the battery to take up the slack for more current. As current demand increases, voltage drop will follow.
Most amps will not do well with less that 10 volts and can become unstable. In fact, this much power draw can actually shut off the engine through power starvation.
My guess, this old Chevette has maybe a 65A ALT and 450 CCA rated battery. This amp probably draws more than 75 amps at full power. If you want to avaoid buring out the present ALT, it may be swapped with a larger current version or tweaked for more output by a good ALT rebuilding shop.
Yes, a larger battery (750 CCA rating or higher will help, as will larger gage wires to ALT/BAT and BAT/GND... but the basic problem is still there... inadequate ALT power.
Call around and see if you can get a higher Ampere rated ALT in that location. I would suggest a minimum of 85A and if possible, make it 100A.
Swez
_Robbob_ on 07/31/2003 20:41:07
The high output alt is a likely necesity i just hope that the original four banger can handle any extra stress the thing doesn't even have power stearing ...
Some body told me that most Gm alt are compatible with other GM vehicles ...makes me wonder if i get a really nice one for the upcoming show maybe i can swap it later with my truck...lol that would be nice...
Thanks again man
P.S. Anyone tell me if Batcaps are all hipe and no go???
http://www.batcap.net/home.htm
They ****claim**** that their smallest battery is worthy of 100 Farads but last time i checked...well i haven't cuz i don't know how to...How do you do math to figure Farads the only time i ever heard of them is with stiffling capacitors not batteries?
Swez on 07/31/2003 21:13:26
Truth is an 800 CCA rated battery is same power storage equivelent of 2,000,000 Farads of storage.
Also, you are correct that GM has a large grouping of ALTs that may fit in that mounting harness and have larger power output than stock. May be a bit harder to retrofit a larger GM alt into that bracket assy... but a cleaver fabrication job can make this work if you have the proper wiring harness for internal regulator etc.
Rebuilds are a lot cheaper and usually have lifetime warranties too. I just bought a 108A for Mom's Buick LeSabre and it costs $66.00 after core charge returned. Lifetime warrantee too. A 10 minute job!
Also, my 120A GM just died and I sent it back to where I bought it 4 years ago. Only had to pay insurance and shipping. It was a rebuilt and died while I was on a road trip... but found a local parts store that had what I needed and replace same ... right in the parking lot in like 15 mins.
It is same shell and casing as the 108A version, but beefier guts. You may get lucky too or have to fabricate a bracket to install a larger ALT in the same location.
Good luck,
Swez
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