View Full Version : Alternator question

10-14-2005, 01:11 PM
My alternator just went on me, and I found a replacement, the only thing is that my old stock one was 114Amps and the new one is 115 amps.

Will using 115 be ok for the car? or will it overload something?

10-14-2005, 01:16 PM
1 amp is not going to kill you, & besides that's suppose to be max amperage so don't worry

10-14-2005, 01:18 PM
didn't think so.. OK thx.

10-14-2005, 02:55 PM
yeah, no problems with that whatsoever. Voltage is the important thing. The accesories in the car will only draw current as needed. so if the total current draw of all your accesories combined was 80amps before...it will still be that after. Increasing the current rating of the alternator will just increase the available current to run more accesories.

10-15-2005, 06:40 PM
yea I had mine rewound to make more amps because my stereo was pulling too much juice... plus I want to make some future upgrades that will involve some massive amps... but yea it wont matter!

10-16-2005, 11:45 PM
i was thinking about getting it rewound, how much did it run you and where did you get it done? What kind of amperage are you now running, and is it still on the factory wiring system?

10-16-2005, 11:48 PM
keep in mind the more amps an alternator produces the harder it is to turn and the more resistance it will have on your accessory drive belt hence impede performance by at least 1/2 a HP.


10-17-2005, 01:21 AM
yea thats true! I had it done at a local alternator rebuild shop...I'll get the info and get back to you...
I'm gettin about 140amps, which is plenty..and it cost me like $200... but he was doing a couple other things so its should be a lot less then that!

10-17-2005, 07:38 PM
i went to a bmw dealership, they check my vin and they said my car already produces 120 amps from the current alternator. I was thinking to upgrading to 180 amps.

So if the alternator puts more strain on the belts, will this cause anything else to get damaged or worn out faster?

10-17-2005, 07:43 PM
it shouldn't really...you might lose a little hp because the crank will work hard now, but it really not going to be noticable. Other than that you shouldn't have any probs. In my case, the alternator belt drives the water pump so if my belt breaks I'm F***ed, so I would suggest looking over it now and then to make sure its not too warn, if it is change it before it breaks or slips off!

10-17-2005, 10:14 PM
a couple extra amps will help pound the subs

10-17-2005, 10:30 PM
i should check it, is that the only other problem that could arise from beefing up the alternator. Would u guys suggest doing it to the one on the car right now, or getting another one and getting that worked on? and this does not affect warranty right??? :(

10-17-2005, 10:34 PM
yea I think it does...basically the way they do it is that they take it appart and add coils into it (the wires that you can see through the casting). Most warranties are void if you take the casting appart. And a good alternator shop can work wonders with any alternator, even old ones, so you would save yourself some good $$$ by using your old one! Take a trip out to an alternator shop and they can test your alternator for the amount of amps that it already makes. The shop I went too charged me for the amount of amps I wanted to get...not by the # of hours spend working on it.