Car Audio and the Alternator of High Output

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porkbone

8 posts

Wannabe Geek

#251265 15-Jun-2019 22:31

I have aftermarket car audio installed. It is messing with my headlights and other electrics. I got a much better battery fitted, didn't fix anything. The vast majority of things that I've read that I've googled have come back with the same advice; forget all else and get a better alternator. However, not one thing I read told me how or where to go to find one.

I have an old people car; 2006 Mitsubishi Colt (Z23, MIVEC, 1.5Ltr FWD Hatch, 4A91). I can easily find a stock/alternative alternator. Hell, every car parts and auto electrical business I called tried to sell me one. I don't want a stock alternator, I want a better one. Over 100 Amp if possible.

I'm pretty lost. I have no idea where to start. I thought calling some companies would give me all the options. It less than didn't.

Do I have to get the exact same shape alternator or can I use any shape?

Any help would be greatly appreciated.

Thanks in advance for your time!

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3885 posts

Uber Geek

#2258940 15-Jun-2019 23:25

How many amps is the factory alternator rated for? Alternators are normally designed to specifically fit each car / engine. Lookup what other Mitsubishi cars have the same engine as your car, lookup what alternator they have. And see if it has a higher rating.

Consider getting a second battery just to run the sound system. And / or a capacitor

Also, lots of modern cars have smart alternator control. Where the ECU varies the alternator output to manage the battery charging and save fuel. The load from the sound system would probably be playing havoc with that system if your car has it.

Get class D amplifiers instead of Class AB. As class D use less power for the same audio output.

I have done lots of alternator stuff over the years. Including making my own voltage regulators and rectifiers. Having fun at the moment with the alternator in my 92 Hilux. It is rated to 70A, but will probably bodge in a 120A alternator from a Holden commodore.

Edit to add.

Some car companies undersize the wires between the alternator and the battery. To make it less likely that the alternator will fail due to overload. Especially if the battery goes flat, car gets jump started then driven straight away. As a flat but otherwise good condition car battery can easily soak up lots of charge current.

lxsw20

3555 posts

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#2258941 15-Jun-2019 23:51

Exactly what audio gear are you running?

Bad earthing or as above under size cabling could cause these sorts of issues too.

Oblivian

7301 posts

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#2258943 16-Jun-2019 00:05

Had some doof doof once that was a bit too grunty. The lights would dim and the car would miss a bit of spark each time there was a descent bass tone.

Fix was to get an oldschool industrial printer and put a cap inline (properly of course). Just like the oldschool show-car audio days. Worked wonders for bolstering those times it needed a bit more current.

Shame they are hard to come by with Class-D doing it for you now.

And yes, as above with car audio and no real earth as it were. Power in = power out. You need to make sure the high gauge cable is used for both the earth and battery in. Lots skip this and end up with alternator whine or not enough juice.

k1w1k1d

1527 posts

Uber Geek

#2258944 16-Jun-2019 00:44

What do you mean by "messing with my headlights and other electrics"?

As previously asked, "Exactly what audio gear are you running?"

Looks like a 2006 Colt with a 4A91 engine has an 85A Mitsubishi alternator. This should be sufficient for most stereo systems?

There are higher output alternators readily available, but I can't see any that would bolt straight on. Fitting one would require a bit of engineering, and beefing up the alternator battery wire etc.

My suggestion would be to show your local auto electrician what the problem is. They can then offer you advice on the best solution to overcome the problem you have.

Sidestep

1013 posts

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#2259000 16-Jun-2019 04:43

Since you've upgraded the battery - and assuming your alternators's outputting it's rated amperage under load (serpentine belt tension?) - the next thing to do's grab a multimeter & test your grounding. Particularly Batt Neg to body, and to engine block

Often just taking off, cleaning and re-sealing oxidised connections (ie alternator, battery, major ground connections) can make a huge improvement.
Simple tools, a piece of fine sandpaper, some dielectric grease (or just vaseline) goes a long way on an older vehicle.

Still no change - upgrade the alt-batt, batt-gnd wiring (you'll be doing that if you install a larger alt anyway..)
Then look at installing a second battery (maybe in the trunk?)

Finally - there's sure to be an alternator upgrade out there. How much trouble are you willing to go to?

Do I have to get the exact same shape alternator or can I use any shape?

The 'shape' doesn't matter. The dimensions do. Particularly the physical size, mounting lug location, pulley size and it's relationship to the mounting points.
As mentioned above, the very first thing to do is find out if your car or engine came with a factory HD alternator.
Maybe give a wrecker/recycler a call - they should be able to provide interchange info.

I've done lots of alternator swaps over the years - shifting the alternator location, running winches, lights, inverters, electric-hydraulic pumps, trailers, custom regulation, multiple batteries..a welder..
If you have to build custom mounts, run custom wiring or do much more than a straight swap you'll need access to a fab shop or $$

sqishy

470 posts

Ultimate Geek

#2259019 16-Jun-2019 09:11

Sounds like you may need an amplifier capacitor....google it.

porkbone

8 posts

Wannabe Geek

#2259064 16-Jun-2019 12:29

lxsw20:

Exactly what audio gear are you running?

Bad earthing or as above under size cabling could cause these sorts of issues too.

My car came with only two really old terrible front door speakers. The two back door speakers had been removed.

I have zero DIY skill for car audio so I took my car to Jonvy and had them install a full basic compliment; kenwood headunit (kmm-bt304), pioneer component speakers (ts-g160c) in the front doors (tweeters were installed on the dash), 6.5" pioneer speakers (ts-g1620f) in the back doors, and one 12" pioneer (ts-w3003d4) with a soundmagus (dk600) in the "boot."

I am happy with the sound I get from this system.

Oblivian:

Had some doof doof once that was a bit too grunty. The lights would dim and the car would miss a bit of spark each time there was a descent bass tone.

Fix was to get an oldschool industrial printer and put a cap inline (properly of course). Just like the oldschool show-car audio days. Worked wonders for bolstering those times it needed a bit more current.

Shame they are hard to come by with Class-D doing it for you now.

And yes, as above with car audio and no real earth as it were. Power in = power out. You need to make sure the high gauge cable is used for both the earth and battery in. Lots skip this and end up with alternator whine or not enough juice.

I have the same issue when I crank up the volume. Unfortunately I have no car audio skill so that printer thing is beyond me, lol.

k1w1k1d:

What do you mean by "messing with my headlights and other electrics"?

As previously asked, "Exactly what audio gear are you running?"

Looks like a 2006 Colt with a 4A91 engine has an 85A Mitsubishi alternator. This should be sufficient for most stereo systems?

There are higher output alternators readily available, but I can't see any that would bolt straight on. Fitting one would require a bit of engineering, and beefing up the alternator battery wire etc.

My suggestion would be to show your local auto electrician what the problem is. They can then offer you advice on the best solution to overcome the problem you have.

When I have my headlights on at night there is some serious dimming if I turn up the volume, the revs drop in my car whenever I'm idle like at stop lights with my foot on the brake and the music is loud, worse if I also turn on my AC, and/or wind up/down the window. Any combination of these things, very noticeable at night when using headlights. I feel like my car is gonna cut out the revs drop so low.

I'm not auto electrical-savvy so I hope I'm making sense. See above for the gear I'm running.

Sidestep:

Since you've upgraded the battery - and assuming your alternators's outputting it's rated amperage under load (serpentine belt tension?) - the next thing to do's grab a multimeter & test your grounding. Particularly Batt Neg to body, and to engine block

Often just taking off, cleaning and re-sealing oxidised connections (ie alternator, battery, major ground connections) can make a huge improvement.
Simple tools, a piece of fine sandpaper, some dielectric grease (or just vaseline) goes a long way on an older vehicle.

Still no change - upgrade the alt-batt, batt-gnd wiring (you'll be doing that if you install a larger alt anyway..)
Then look at installing a second battery (maybe in the trunk?)

Finally - there's sure to be an alternator upgrade out there. How much trouble are you willing to go to?

The battery is pretty clean, in fact the whole engine bay is in pretty good condition. I'd have to get a pro to check the grounding and I was thinking about just getting 4 gauge wire installed anyway and as for how much trouble, well, if you consider I know very little about the whole thing, I'm already having a lot of trouble so more probably wouldn't hurt much, lol.

To add, this is one that Repco says fits my car: https://www.repco.co.nz/en/brands/oex/alternator-12v-75a-mitsubishi-style-mxa360/p/A1192648

This is one that looks similar: https://www.repco.co.nz/en/parts-service/electrical-parts-vehicle-management/alternators/oex-alternator-12v-120a-mitsubishi-style-mxa324/p/A1135438

Thoughts?

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richms

28191 posts

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#2259068 16-Jun-2019 12:50

Check the battery is full, if its "new" it might not be that full. If you're never reving it then its never charging. The rated power of alternators isnt at idle, its when you have things moving so if you just park up and play tunes at idle, it will be draining it. Even having lights and aircon on in small cars can take more out than the alternator produces at idle.

But first, check the grounds. Upgrade them if they are tiny little things. No point putting in fancy power cable if the ground straps are still the tiny little one that was cost engineered down the the smallest size one that would let the car crank and start.

Richard rich.ms

Aredwood

3885 posts

Uber Geek

#2259069 16-Jun-2019 12:57

That first alternator has a vacuum pump fitted to it, meaning it is intended for a diesel engine. So it definitely wont be the right one for your car. And it's output is unlikely to be higher than what the factory one could provide anyway.

And the second one has a different plug compared to the first one.

Note that Mitsubishi made alternators that were fitted to lots of other car brands.

Have you tried going back to the place that installed the stereo system and asking them what should be done to fix the problem?

Have you confirmed that the alternator is definitely undersized? And that you dont have a wiring fault, faulty alternator, slipping drive belt etc?

ratsun81

508 posts

Ultimate Geek

#2259070 16-Jun-2019 13:09

porkbone:

I have aftermarket car audio installed. It is messing with my headlights and other electrics. I got a much better battery fitted, didn't fix anything. The vast majority of things that I've read that I've googled have come back with the same advice; forget all else and get a better alternator. However, not one thing I read told me how or where to go to find one.

I have an old people car; 2006 Mitsubishi Colt (Z23, MIVEC, 1.5Ltr FWD Hatch, 4A91). I can easily find a stock/alternative alternator. Hell, every car parts and auto electrical business I called tried to sell me one. I don't want a stock alternator, I want a better one. Over 100 Amp if possible.

I'm pretty lost. I have no idea where to start. I thought calling some companies would give me all the options. It less than didn't.

Do I have to get the exact same shape alternator or can I use any shape?

Any help would be greatly appreciated.

Thanks in advance for your time!

First things first, you need to confirm that your current alternator is working properly. These are a wear component on a vehicle.

Go to an auto sparky or a dedicated battery shop and they can do a draw test on your car to see where the issue is.

The list of audio gear you gave should not need a more powerful alternator.

If its not an alternator issue it would be most likely poor grounding/wiring.

porkbone

8 posts

Wannabe Geek

#2259076 16-Jun-2019 13:39

richms:

Check the battery is full, if its "new" it might not be that full. If you're never reving it then its never charging. The rated power of alternators isnt at idle, its when you have things moving so if you just park up and play tunes at idle, it will be draining it. Even having lights and aircon on in small cars can take more out than the alternator produces at idle.

But first, check the grounds. Upgrade them if they are tiny little things. No point putting in fancy power cable if the ground straps are still the tiny little one that was cost engineered down the the smallest size one that would let the car crank and start.

OK, I will go visit an auto electrician and get them to check the grounds. Seems to be the overall consensus so far. I don't often park up and play tunes for the reasons mentioned, stop light paranoia is beginning to take root, lol.

Aredwood:

That first alternator has a vacuum pump fitted to it, meaning it is intended for a diesel engine. So it definitely wont be the right one for your car. And it's output is unlikely to be higher than what the factory one could provide anyway.

And the second one has a different plug compared to the first one.

Note that Mitsubishi made alternators that were fitted to lots of other car brands.

Have you tried going back to the place that installed the stereo system and asking them what should be done to fix the problem?

Have you confirmed that the alternator is definitely undersized? And that you dont have a wiring fault, faulty alternator, slipping drive belt etc?

Wow. Repco recommending something so wrong blows my mind. I suppose my first mistake was going to Repco in the first place, lol. So it seems that going to an auto-electrician and having them do a draw test and a grounding check is my first port of call before I buy things I might not need.

ratsun81:

First things first, you need to confirm that your current alternator is working properly. These are a wear component on a vehicle.

Go to an auto sparky or a dedicated battery shop and they can do a draw test on your car to see where the issue is.

The list of audio gear you gave should not need a more powerful alternator.

If its not an alternator issue it would be most likely poor grounding/wiring.

Ok, thanks, I will shop around for an auto-electrician and see what they have to say.

To add, does anyone think also having the auto-electrician or a mechanic turn the revs up a smidge so my car idles at a higher rate is a good idea? Or will fixing the electrical issue whatever it may be also fix that problem too?

Cheers.

wsnz

649 posts

Ultimate Geek

#2259127 16-Jun-2019 15:07

porkbone:

To add, does anyone think also having the auto-electrician or a mechanic turn the revs up a smidge so my car idles at a higher rate is a good idea? Or will fixing the electrical issue whatever it may be also fix that problem too?

Cheers.

Not much point really, as you are potentially drawing more current than the alternator can provide even at high(ish) rev's. You need to address the root cause of the issue first.

I had a similar issue in a car of mine many years ago; upgraded the battery, added a cap and the issue went away. It would also pay to make sure that you've correctly matched the speakers with the appropriate amp. I've seen a lot of installs where the amp is excessive for what the speakers (especially a sub) can cope with.

porkbone

8 posts

Wannabe Geek

#2259129 16-Jun-2019 15:19

wsnz:

Not much point really, as you are potentially drawing more current than the alternator can provide even at high(ish) rev's. You need to address the root cause of the issue first.

I had a similar issue in a car of mine many years ago; upgraded the battery, added a cap and the issue went away. It would also pay to make sure that you've correctly matched the speakers with the appropriate amp. I've seen a lot of installs where the amp is excessive for what the speakers (especially a sub) can cope with.

How many farads is needed for a capacitor to be useful?

gzt

17155 posts

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#2259131 16-Jun-2019 15:23

Aredwood: Have you tried going back to the place that installed the stereo system and asking them what should be done to fix the problem?

This. Any competent audio shop has seen it all over the years.

Oblivian

7301 posts

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#2259132 16-Jun-2019 15:26

1-2. But they don't run cheap.

No cheap way of telling if that will suffice. You'll need to see someone that's willing to put time in to find the cause, rather than take your money and throw a few nice looking things off a shelf at it.

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