Suggestions for and alternator upgrade

[VAL]

Suggestions for an alternator upgrade

Looking to upgrade my alternator. I put in some H4 headlights with lmc wiring harness, and the current set up ain't getting it done, lights go dim at idle, then go to normal brightness at higher rpm's. Anybody have any recommendations?

 

[towman]

find a local rebuilder and have them up grade it

 

[HotRodPC]

Have you seen the recently posted Headlight rewire thread using relays to make sure you're getting the full battery and alternator voltage to your headlight circuit?

 

[smurph20]

This is what im running on mine.

http://www.painlessperformance.com/webcatalog/lv.php?sl=30815

 

[HotRodPC]

This is what im running on mine.

http://www.painlessperformance.com/webcatalog/lv.php?sl=30815

I thought there was a thread showing a schematic and how to do it yourself too.

 

[HotRodPC]

But BTW, keep in mind the thread is about Alternator Upgrade which is good option too. Do you what amperage alternator you have now?

 

[smurph20]

I know im only running a 62 amp now and even with my high beams on 100 watt 6 inch wannabe KCs in the front on and my stereo cranked up im still pushing 14.5 or so.

 

[HotRodPC]

I need to get some research done myself on this. I plan on running some accessroies like Air compressor, winch, off-road lights etc etc, so I'm going to be going with a dual battery set up and I want it isolated, along with the Big 3 uprade and the upgraded 100+ amp alternator. I don't want to have any power issues at all, and want back up power available if my main battery goes dead.

 

[HotRodPC]

Looking to upgrade my alternator. I put in some H4 headlights with lmc wiring harness, and the current set up ain't getting it done, lights go dim at idle, then go to normal brightness at higher rpm's. Anybody have any recommendations?

I do agree a higher amp alternator is a good idea Val, but I do think this headlight relay and the Big 3 upgrade will most likely fix your issue. What that headlight wiring does it makes your lights get power direct off the battery without running through the charging system. So if you're idling at a light, it should be be direct 13.8-14.2 volts, then when you get going the alternator will continue charging the battery and get it caught back up. Don't leave your lights on though with the motor running. I bet those will draw you battery power down pretty quick. Might consider one of the real nice Red or Yellow Top Optimas too.

 

[HotRodPC]

good reading on alternators on here, http://madelectrical.com/electrical-tech.shtml and some other electrical theory

Thanks Chris. This is what I thought I had seen recently about brighter headlights. Included within that link above.

http://madelectrical.com/electricaltech/brighter-headlights.shtml

 

[VAL]

I do agree a higher amp alternator is a good idea Val, but I do think this headlight relay and the Big 3 upgrade will most likely fix your issue. What that headlight wiring does it makes your lights get power direct off the battery without running through the charging system. So if you're idling at a light, it should be be direct 13.8-14.2 volts, then when you get going the alternator will continue charging the battery and get it caught back up. Don't leave your lights on though with the motor running. I bet those will draw you battery power down pretty quick. Might consider one of the real nice Red or Yellow Top Optimas too.

I've already done the harness with the relays, and I got the big 3 also. When I had my stock headlights they worked very well. The H4's are pulling a lot more juice, and that's why I believe I need an alternator upgrade. The alternator I have is a duralast from autozone, I believe its supposed to be putting out 90 amps, although I have my doubts on that, just because its a duralast.

 

[HotRodPC]

I've already done the harness with the relays, and I got the big 3 also. When I had my stock headlights they worked very well. The H4's are pulling a lot more juice, and that's why I believe I need an alternator upgrade. The alternator I have is a duralast from autozone, I believe its supposed to be putting out 90 amps, although I have my doubts on that, just because its a duralast.

Well, I'm a believer in the Duralast Gold batteries. They're made by Johnson Controls and pretty much equal to a Die Hard without the Die Hard price. I'd have to agree with you if you've done all that already. And you're not running any kind of underrun pulleys right??? Do know what amperage alternator you're running now? Are you on a Serpentine system or the old V Belt? This will also matter.

 

[VAL]

Well, I'm a believer in the Duralast Gold batteries. They're made by Johnson Controls and pretty much equal to a Die Hard without the Die Hard price. I'd have to agree with you if you've done all that already. And you're not running any kind of underrun pulleys right??? Do know what amperage alternator you're running now? Are you on a Serpentine system or the old V Belt? This will also matter.

I have the original v-belts that came with the truck, don't know what the term underrun pully means, and my current alt is supposed to be at 90 amps.

 

[HotRodPC]

I have the original v-belts that came with the truck, don't know what the term underrun pully means, and my current alt is supposed to be at 90 amps.

Yes, there is a stronger alternator. I'm wanting to say it's a 105 amp. and maybe even another bigger than that, but it's in a bigger housing too. And you should be OK with a bigger housing if you're running V belt. If you're not sure what the underrun pulleys are, then you don't have them. They are afermarket and usually used for high performance vehicles, where the the accessories like Alternator, Waterpump, PS pump etc, actually turn slower so they're not robbing as much horsepower from the motor and it can be common they'll have issues at idle like you mention. Hopefully someone else will chime in and confirm these alternator sizes. I know on the Serpentine setup, the upgrade alternator requires some bracket mod cuz the bigger housing hits the mounting bracket so it needs notched.

 

[notverrysmart]

Your first step, if you haven't already should be to check your voltage drop the way they did in the link HRPC posted. Except you will be with engine idle instead of highway rpm and with headlights on low beam (assuming that is where you have the H4's. The wiring harness you have from lmc should be the same as the relay mod they talk about in there. As long as your voltage drop is within tolerance then that part is good and time to check your charging system. A cheap battery will somewhat mimic the signs of a low output alternator as will a battery that is not fully charged. Make sure you have a good battery (doesn't have to be an optima red/yellow top) and hook up a battery charger to make sure it is fully 100% charged. If this makes the problem better temporarily and the battery is old or has been run dead a few times it is a good idea to get a new battery too.
As for the alternator upgrades, if you do go with one that has a bigger housing below is the bracket I had to make for my 200amp to fit.

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sorry about the angle, don't have a pic straight from the front.
When looking at new alternators make sure you check the rpm it is rated at, my 200amp at idle could not handle my electric fan, but holding it at 1000rpm brought it back.