High-Output alternator

TC Yota

New Member
I recently bought a High-output alternator for my toyota 3.4 engine. It works great at high rpms but doesn't seem to charge good at lower rpms. Am I correct in assuming that's normal because they are made to perform better in the higher rpms? It charges fine when I'm not running all my lights and such, just when I kick them all on I have to keep the rpms up
 

JasonHutter

Well-Known Member
We have been trying to run a high-output alternator on our race truck with no luck. We have 7 non HID's on the truck and have never been able to run a race with all the lights on. They tell us the alternator is suppose to put out 150-200 amps and it just isn't happening. The lights are using 8amps each which is 56amps, our rear amber which we will call 8amps, the computer and ignition which I don't know the draw, fuel pump, electric radiator fan, and brake lights every now and then! So we are looking at 64 amps plus the things I haven't added in but I can't imagine that would put us over 150 amps. We are going to be looking to buy HID's before our next race that goes into the night.

Jason
 

NicksTrix

Well-Known Member
what size pulley are you running? smaller the better to get it spinning as fast as you can.
are you running v belt or serpentine? very hard to get max amps out of a v belt.
if you are running a v you might want to double it up if you can to get more grip.

are you running heavy enough cable as well to the battery?
you can get the alt tested and see if it honestly is capable of putting the amps out. if it is and you are seeing it you know where you need to start working to get the performace you need and should be getting.

hth
N
 

D.Mavis

Well-Known Member
I used an alternator from an ambulance. since then I've seen them on buses too. they are physically large so you'd have to custom mount it, but it performed well, Iassume it was charging fine at all rpm's we used 7 halogens 100watt a piece, never had an issue. it had a double v-groove but I used one with no problems.
 

_

Well-Known Member
Alternators and proper installation/operation of alternators is one of the most mis-understood aspect of proper wiring.

1st, You need to calculate proper pulley size. A general rule of thumb is, 140mm alternators are rated to approx 14,000 continuous rpms, 130mm are rated to approx 15,000 continuous rpms and 120mm alternators are rated to approx 16,000. Calculate out your alternator rpms by multiplying your max engine rpms (rev-limiter setting) by your crank to alternator pulley ratio. Change your pulley sizes until you are close to the numbers above. Operating your alternator at the maximum rated rpms will not only increase the output efficiency of your alternator, it will aid in cooling potential of the alternator internal/external cooling fans.

2nd, Insure you are using the appropriate wire gauge from the B+ on the alternator to your battery. Google "Wire gauge calculator" and you will come up with several on-line wire gauge calculators for determining appropriate gauge. You want to shoot for no more than a 1/2 volt drop from your alternator to your battery at max alternator output.

3rd, In my opinion, avoid the one wire alternators. Alternators have a sense lead for a reason, to sense the necessary output to insure your instrument panel has 14.0 to 14.2volts at all times. This sense lead will aid in overcoming excessive voltage drop as components are cycled on and off, and aid in eliminating over charging which can cause premature battery failure. While these 1-wire units may be easier to install, they are not operating in the most effective manner.

4th, Insure you are not experiencing belt slippage. If you are running a V-belt, anything in excess of 140 amps output should utilize a 7/16-1/2 inch wide belt over the more common 3/8 inch wide belt. Not only is the wider belt stronger, it has greater contact surface area aiding in preventing slippage.

5th, Your problem may not even be related to your alternator. Unless you have a proper current clamp, you have no knowledge of the actual amperage your alternator is putting out. So, to say your alternator is not putting out enough "AMPS", may be an inaccurate assumption.

You must insure all wire sizes in your vehicle are appropriately sized for their respective current load. So, calculate and/or properly measure actual current draw. Then use the above on-line calculator and insure the wire size to your instrument panel and on to your actual components are of adequate size. Or, use a volt meter attaching the negative lead to the +12V wire at the component, and the positive lead to the positive post of your battery. The reading on the volt meter will tell you voltage loss for any given component you measure. Automotive industry standards are to have no less than 1 Vdc loss to any component. If you have in excess of 1 1/2 to 2 Vdc loss, your problem may be outside of your charging system. You need to perform the volt meter test with all components operating simultaneous representing worst case continuous draw.

If you have additional questions, feel free to send me a pm.
 

yotatoy

Member
what size wire are you running to the battery? I would run at least a 4 gauge since it's a high output alternator.
 

JasonHutter

Well-Known Member
I appreciate all the info! I have to drive 2hrs to get to the shop we work on the truck, I will start going over all this next time I am down there.

Jason

Oh yeah, we are running a 0 or 1 gauge wire back to the battery if my memory serves me correct.
 

partybarge_pilot

Well-Known Member
I recently bought a High-output alternator for my toyota 3.4 engine.
All of the off the shelf HO alternators I have seen for Toy's aren't worth their weight in scrap. Take it to Richer auto electric in Oceanside and have them go through it. You will then have a working unit that will last for years.
 

BCG1

Well-Known Member
All of the off the shelf HO alternators I have seen for Toy's aren't worth their weight in scrap. Take it to Richer auto electric in Oceanside and have them go through it. You will then have a working unit that will last for years.
How many have you seen? How many have you tested? Aren't you the same guy who said that all Chinese HID kits sucked?
 

RocketMan

Well-Known Member
Easy there #1, Partybarge pilot has 3239 more posts than you ....he must be omnipotent.......
 

partybarge_pilot

Well-Known Member
How many have you seen? How many have you tested? Aren't you the same guy who said that all Chinese HID kits sucked?
Well, between Me and My buddies I've seen 3 Toyota units. All 3 were junk. The Powermaster unit I bought for the Barge was also junk as confirmed by the guys at Richer Auto Electric. After having them build Me an alternator, My problems ended. I've have since used them on several race cars also with good results.
 

Sparky

Well-Known Member
Well, between Me and My buddies I've seen 3 Toyota units. All 3 were junk. The Powermaster unit I bought for the Barge was also junk as confirmed by the guys at Richer Auto Electric. After having them build Me an alternator, My problems ended. I've have since used them on several race cars also with good results.
Interesting. We have been running a Powermaster on our racer with zero problems - 18 consecutive race finishes. We also had one on our old 8 truck and never had a charging problem on it either.
 

dezerts10

BANG!! BANG!!
how do i decided what altenator to run? i have a 2002 4.3L v6 but it not going to be any where near stock so no wiring harness. i have heard i just need to get a HO chevy altenator like people use on hot rods.
 
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