Fire67
11-07-2008, 01:48 PM
I decided to quit being so rude and hijacking 96silverram's thread. So I started this one. We did however talk alot about my situation on his thread, so here's the link for anyone that wants to catch up: http://ltxtech.com/forums/showthread.php?t=1531
Anyway. I did some testing last night. And did a basic job of adding up my amp draw based on the electrical Items I have running.
I did all this with a brand new battery, and a brand new altenator (autozone lifetime warranty exchange).
Here's my voltage data:
Car Off:
Battery voltage (at terminals) = 12.5v
Voltage at distribution block (up front) = 12.49v
Car running cold (fans off):
Battery voltage (at terminals) = 14.08v
Voltage at cutoff switch = 14.14v (this is were the alt. charge feed into the system)
Voltage at distribution block (up front) = 14.03
Voltage at altenator = 14.44
Car running warm (fans on):
Battery voltage (at terminals) = 13.6v
Battery voltage (at switch) = 13.58v
Voltage at distribution block = 13.58v
Voltage at altenator = 14.2v
If I bring rpms to about 2500 when warm, the MSD ignition draws enough additional amperage to cause the available voltage to steadily drop.
This leads to amperage available vs. vehicle demand. I added up known amp draw for the ignition, and used the fuse values for everything else. I know this is not actual amp draw, it's slightly over actual draw but I could not get actual data so this should give me a 'safety' margin.
MSD digital 7 plus = .7amps per 1000 rpm
FAST system = 1x 3amp fuse, 1x 30amp fuse (33amps)
H20 pump = 20amp fuse
Gauges (stock and aftermarket) = 10amp fuse
Sensors (stock) = 20amp fuse
Fuel pump = 30amp fuse
Fans = 25amp fuse
Total at idle (fans on) = 138.7
Total at 2500rpm cruise = 139.75
Total at 6500rpm = 142.55
I do not have values figured in for my Alky injection system, lights (interior / exterior), trans brake, line lock, etc. But any of these, even breifly would put me well over the available amperage from the altenator.
I also did a couple experiments bypassing my normal charge wire. I ran zero gauge from the altenator to the switch out back, and I tried a short section of 2 gauge from the altenator to the distribution block up front. Neither of these experiments improved my situation at all.
After doing all this and collecting all the data I could, I believe that I just need a higher amp altenator. Powermaster makes a 200amp one for $360
Then I've heard of people modifying stock altenators to get more amperage out of them. So I'm thinking of finding an altenator shop to see if they will set mine up for less than a powermaster unit costs.
Anyone not agree with my lack of amperage theory? If so please explain.
Anyone have any other suggestions?
Anyone know what it takes to modify an altenator?
Anyway. I did some testing last night. And did a basic job of adding up my amp draw based on the electrical Items I have running.
I did all this with a brand new battery, and a brand new altenator (autozone lifetime warranty exchange).
Here's my voltage data:
Car Off:
Battery voltage (at terminals) = 12.5v
Voltage at distribution block (up front) = 12.49v
Car running cold (fans off):
Battery voltage (at terminals) = 14.08v
Voltage at cutoff switch = 14.14v (this is were the alt. charge feed into the system)
Voltage at distribution block (up front) = 14.03
Voltage at altenator = 14.44
Car running warm (fans on):
Battery voltage (at terminals) = 13.6v
Battery voltage (at switch) = 13.58v
Voltage at distribution block = 13.58v
Voltage at altenator = 14.2v
If I bring rpms to about 2500 when warm, the MSD ignition draws enough additional amperage to cause the available voltage to steadily drop.
This leads to amperage available vs. vehicle demand. I added up known amp draw for the ignition, and used the fuse values for everything else. I know this is not actual amp draw, it's slightly over actual draw but I could not get actual data so this should give me a 'safety' margin.
MSD digital 7 plus = .7amps per 1000 rpm
FAST system = 1x 3amp fuse, 1x 30amp fuse (33amps)
H20 pump = 20amp fuse
Gauges (stock and aftermarket) = 10amp fuse
Sensors (stock) = 20amp fuse
Fuel pump = 30amp fuse
Fans = 25amp fuse
Total at idle (fans on) = 138.7
Total at 2500rpm cruise = 139.75
Total at 6500rpm = 142.55
I do not have values figured in for my Alky injection system, lights (interior / exterior), trans brake, line lock, etc. But any of these, even breifly would put me well over the available amperage from the altenator.
I also did a couple experiments bypassing my normal charge wire. I ran zero gauge from the altenator to the switch out back, and I tried a short section of 2 gauge from the altenator to the distribution block up front. Neither of these experiments improved my situation at all.
After doing all this and collecting all the data I could, I believe that I just need a higher amp altenator. Powermaster makes a 200amp one for $360
Then I've heard of people modifying stock altenators to get more amperage out of them. So I'm thinking of finding an altenator shop to see if they will set mine up for less than a powermaster unit costs.
Anyone not agree with my lack of amperage theory? If so please explain.
Anyone have any other suggestions?
Anyone know what it takes to modify an altenator?