SPOautos

This isnt about stereo stuff but I'm sure some of you stereo guys can help me out with some info. I have a lot of things in my car that pull a lot of amps and I'm afraid that I'm going to pull more amps than the alt can put out. What do I need to do about that?

What I've got is this....
dual fuel pumps
electric water pump
upgraded radiator fans
stereo amp
msd ignition amp

I'm afraid that all of that stuff along with headlights and the rest of the cars electrical might be more than the alt can put out. Anyone know how much room there is between how many amps the car pulls and what the alt is capable of in stock form? Then I can see if my add ones will fit into that margin

Any advice would be appreciated.

Railgun

Stock alt is 100 amp. You can get 200 A alts, but they'll be expensive. How much the car actually draws is dependant on a lot of things.

Herblenny

iTrader: (13)

How about some sort of Capacitors to hold charge?? Isn't that what high thumping system uses capacitors for? Maybe a capacitor in between your stereo.. I think one bad thing about caps are that you can hook it up to your fans or your fuel pumps.. it has to have constant hot wire. I believe??

Montego

iTrader: (1)

I know where Herbleny is coming from. But in this instance, a cap will not help if your car actually draws more power than it puts out.

To know for sure you could just add the power output of the all the stuff you mentioned and compare it to what output the alternator is.

Herblenny

iTrader: (13)

Montego,

how about 2 batteries with seperate charging system.. i forgot what that was called.. splitter of some sort (distributor??) I know some of the car stereo guys do this also to compensate for all the amps and stuff..

Railgun

Ultimately you're going to need a bigger alternator. If you have two batteries, that will help with the peaks from a stereo, but you'll eventually wear them dead as they're still not going to get enough juice to keep them fresh from the stock alt. With the above mentioned setup, yeah, you might have a battery solely for the audio, but the alternator is still charging them both and seeing the same load.

http://www.jegs.com/cgi-bin/ncommerc...01&prmenbr=361
http://www.jegs.com/cgi-bin/ncommerc...51&prmenbr=361
http://www.jegs.com/cgi-bin/ncommerc...96&prmenbr=361
http://www.h-o-alternators.com/alternators.htm
http://www.lazartronics.com/store/ca....htm/cPath/243

Some modification may be required.

David88vert

Railgun is 100% correct. IF you are drawing more than 80 amps, you are going to need a larger alternator. The only place that I will go to for an upgraded alternator for an FD is powermaxx.com. Talk to Marvin Crawford, he is the owner. I'm getting one right now from him.

DamonB

First you need to figure out how much current you're pulling. I highly doubt that what you have listed is too much for the stock alternator.

pianoprodigy

I have a 200A alternator in my car. It puts out 100A at idle. My car pulls 90A at idle with the following components on:

2 fuel pumps
4 electric fans
3 MSD Ignition Boosters (6As, I believe)
AC On
Microtech w/ dash display
Profec B Spec II
Eclipse HU
2 Amplifiers

I was killing my Red Top Optima battery before the alternator because the stock one couldn't keep up. The 200A alternator was made by a local guy who outsources to Stinger. It cost $450 and has a 1-year warranty. I've had it for about 2 months and have had no charging issues at all.

Herblenny

iTrader: (13)

Wow! that's awesome piano! Do you have any pics you could post?? I would like to see how it mounts.. or is it stock housing with different internal?

pianoprodigy

Different housing, same mounting location with modified brackets. I'll take a picture when I get home.

pianoprodigy

My dirty engine bay compliments of the ******** beach police station (total of 6 squad cars) that won't let me cut through 20 feet of their parking lot to avoid dusty road construction

You can see where I just dragged my finger over the alternator...

gdnimr0d

iTrader: (4)

thats a very very nice setup...kind of costly but it looks like it is working great for you...nice

Herblenny

iTrader: (13)

Looks great! Alternator looks mean.. I guess it is since its pulling 200A.

And those three MSD's makes it look even more scary!

Looks awesome!

v86_wankelfan

Yea, but to generate that extra electricity the alternator is taking power away from the engine. I'm sure how much slower it's actually making it run though.

pianoprodigy

The guy who built the alternator said it would rob 7 hp when it was maxxing out the amperage. It had to be done, so I didn't have a choice in the matter. Actually, I haven't noticed any power loss, but that's really hard to measure.

pianoprodigy

Everyone always asks "Why do you have 3 MSDs!?!" The previous owner who installed that setup was shooting for 600 whp ( ) on this motor, but he never had a chance to try since he sold the car when the engine and turbo only had 300 miles on them.

gdnimr0d

iTrader: (4)

hmmm so why do you say the 200A alternater had to be done.....was the stock 100A just not lighting everything up well enough or were things not even turning on unless your car was under a load...?

pianoprodigy

All the car's electrical components were drawing too much load so that the original alternator could not keep up. I purchased a Bosch rebuilt alternator which improved the situation slightly, but still was not sufficient. The stock 100A alternator only puts out about 40A at idle. All my car's electrical components draw 90A. If the alternator cannot supply the necessary power, the battery has to pick up the slack. If the alternator cannot even keep up with the ongoing demand, it will never be able to charge the battery. Therefore, the battery will just supply juice until it dies. I didn't HAVE to replace the alternator to drive the car, but I got really tired of asking for jump starts. Now, I have an alternator that produces 100A at idle which is enough to keep up with the ongoing current draw and still charge the battery.

pianoprodigy

I failed to finish my thought here. I usually just say "It's completely overkill. It is already mounted and wired, so why would I remove it?" They do kill spark plugs though. I have them checked and, if needed, replaced every 2k miles.

gdnimr0d

iTrader: (4)

hmm thats very smart...thats really cool...now that you explained it i understand your situation more....glad i don't need that for my car hehe as i have the pc680 and the power of that battery is small enough already. thanks and peace out

SPOautos

Thanks for the info guys!!! Its funny, I've been super busy and actually forgot I started this thread till Herblenny mentioned some of this info to me.

So if mounting the alt wasnt a concern what would you get? Basically here is my situation, if I go with a elec water pump I have to relocate the alt anyway which means custom brakets. Basically I could use any alt I wanted to since I have to make brakets no matter what.

Anyone has a suggestion (not sure if I want to spend $450 for a alt though....ouch)

This would look real nice hanging on the side of my engine where the PS goes, it would match all my polish I have haha
http://www.jegs.com/cgi-bin/ncommerc...01&prmenbr=361

jpandes

Pianoprodigy,

How did you figure out how many amps your car is drawing? I'm also sick of jump starting my car.