I'd like a high performance alternator similar to one of these. Is it possible to rebuild a stock alternator to similar output, using majority of tools one would have at a home garage? Of course one or two specialty tools might be involved, but if it's pheasible to diy and 25-50% off the cost then it seems almost worth it.

  • How much power do you really need? In other words, do you really want to sacrifice at least 10 HP making electricity?? Apr 29, 2013 at 20:19
  • @R.. this isn't a race car, this is for a car audio setup, but why would I have to sacrifice HP?
    – MDMoore313
    Apr 29, 2013 at 20:26
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    @MDMoore313 The extra wattage comes directly from the horsepower of the engine. The more load on the alternator the less power is going to the wheels.
    – Mike Saull
    Apr 29, 2013 at 20:41
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    Well another way to look at sacrificing HP is that, when the engine's not operating at peak output, you're burning more gas to get the same amount of HP/same acceleration... Apr 29, 2013 at 21:36
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    Well I don't know if just having the higher amperage alternator itself will cause more parasitic drag but it definitely will if you throw an extra 2000w of draw on it. Theoretically though the most that should take should be around 4-5 horsepower depending on the inefficiencies though.
    – Mike Saull
    Apr 29, 2013 at 22:08

3 Answers 3


Disclaimer: This isn’t a qualified answer, but I thought it could be useful addition above that of a comment.

I’ve looked into DIY coil repair before, and while such operation is possible (including winding the coils taut using hand drill or bench press), it’s not advisable for a novice. Beside the difficulty of producing a decent coil, even more so difficult is to ensure the sealing and/or insulation of the coil. As far as failures go, that would appear the primary cause in the first place, and a shade-tree mechanic without proper knowledge of electrical engineering and manufacturing practices is not likely to succeed (I’ve read of people’s repaired stators shorting out in several months).

However people do repair automotive coils (generators, ignition etc.), and do rewind them for higher output. It could be advisable to find a specialist either locally, or over the Internet (you’d have to send the device for them to rewind which incurs additional cost).


No. You could probably fix a broken one by rebuilding it but I doubt it is easy to up the amperage value. You would have to replace the coils with higher windings I doubt you could do this in the average garage.

Worth looking into I guess but I wouldn't hold your breath.


Well if you have the expertise to rebuilt the entire winding and replace worn out bushes, then yes, it can be termed as a DIY project. However many people are not well versed with electrical motor winding and you may need an experts help. Before you do that, you may refer to automotix.net/autorepair/diy/ which has many DIY technique on repairing and serving motors and engines of several models. This should help in making your DIY project successful.

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