Alternator amperage

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Trevor

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Im putting a sandcar together, and looking at different alternators. Im doing the F Body belt line.

My main question is I see that redline sells a 240 amp alternator for upwards of $500 that was recommended to me. Im no baller, that just seems crazy expensive to me for an Alternator. I need some schooling on what is necessary and if they are worth the money. Im not gonna run all the much stuff. Not a ton of lighting, whips, intercom/radio, all the normal stuff

ive seen some other brands with 220 amp alternators for around $180. What have you guys have luck with
 
Are you planning on welding with it???

You would need some monster cable to be safe with that amperage!

2/0 Gauge 2/0 AWG 10 Feet Red + 10 Feet Black Welding Battery Pure Copper Flexible Cable + 10pcs of 3/8" Tinned Copper Cable Lug Terminal Connectors + 3 Feet Black Heat Shrink Tubing https://a.co/d/bsEo8b9

If you were powering a full size EMT vehicle, with ten batteries, you MIGHT need that much power.

I've been using these guys products for years with no issues. Call them and see what they say. 👍🏼

 
I talked to the guy at the Sand Sports Super Show that has the alternator shop: AutoTech Engineering. He was very knowledgeable and and seemed like he could build an alternator to fit pretty much any engine and any amperage level you want. He was very helpful.
I would think he would be a good guy to talk to, especially if your looking for something higher than stock amperage.
AutoTech Engineering Sam DeSantos

Prices vary of course, but the numbers he was talking for various builds we more like $350 or so if I remember correctly.
 
rivermobster said:
Are you planning on welding with it???

You would need some monster cable to be safe with that amperage!

2/0 Gauge 2/0 AWG 10 Feet Red + 10 Feet Black Welding Battery Pure Copper Flexible Cable + 10pcs of 3/8" Tinned Copper Cable Lug Terminal Connectors + 3 Feet Black Heat Shrink Tubing https://a.co/d/bsEo8b9

If you were powering a full size EMT vehicle, with ten batteries, you MIGHT need that much power.

I've been using these guys products for years with no issues. Call them and see what they say. 👍🏼

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there are at least three cars in my group that run that big amperage alternator that Redline sells. Im not knowledgeable on these hense the post, just trying to learn and buy the right thing for my application trying not to break the bank
 
My Jeep is running the 145A alternator that came with my 5.3 from a suburban. Running 800w in fans, halogen headlights, AC, defroster, offroad lights, inverter, stereo, etc etc etc. Sometimes dips to 13.4v at the sub-500rpm stock idle. Always 14v once driving.

In a buggy? No clue why you’d need anywhere near that kind of amperage. Biggest thing with any of them is to watch overall speed. It’s super easy to overspin them on a hopped up motor.
 
A stock alternator is around 100 amps. That’s what I have in my car. With all my lights, fans, fuel pump, ECU, gauges, etc on I’m probably using 80 amps or less. But I don’t have a stereo with a bunch of speakers or a radio.
Best way to determine what amperage alternator you need is to add up everything you want to have on in your car and give yourself a little margin.
Most items are listed in either amps or watts. If it’s watts, divide by 12 to get amps.
The alternator will only put out the required amount of amps depending upon the load. So if you install a 220 amp alternator and the required load for your car is 100 amps (1200 watts) the alternator will only put out 100 amps.
P=IxE
“P” is power in watts equals “I” is current in amps times “E” is voltage.
 
I have 134 Amp requirement with all of my stuff running.
I was going through the smaller amperage alternators.
I bought the 240 Amp alternator from CBM with the larger pulley (as stated above, to slow it down).
Been good ever since.
As stated, all depends on your power requirements.
 
lincster said:
I have 134 Amp requirement with all of my stuff running.
I was going through the smaller amperage alternators.
I bought the 240 Amp alternator from CBM with the larger pulley (as stated above, to slow it down).
Been good ever since.
As stated, all depends on your power requirements.
Click to expand...
Lincster has enough fans/pumps to for a flying reactor though. 🤣
 
This is exactly why i love this forum. It all makes sense. I went with a 110 amp ac delco and we’ll see how she does. Thanks so much guys
 
@J Alper posted an ebay higher amp alternator in another thread. Unfortunately I can’t find that thread. I used that same brand on a Toyota and it is still running fine. Less money than a powermasta.
 
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I run an ACDelco 105amp alternator from Auto Zone on my LS6. It's easy to get replaced if it goes out. So far so good. I calculated my needs one time, and it was in the 94amp range. So, there is not much headroom but that is with everything turned on.
 
Contact me i can get you going in the correct direction,
depending on the demand,
160 amp is good for most, they should be around $150
220 amp factory is around $180
Billet Mechman will run close to $500

To make it last it not the alternator it how you spin it,
Even a $500 mechman will not last a season if it is not setup correctly,
 
J Alper said:
Contact me i can get you going in the correct direction,
depending on the demand,
160 amp is good for most, they should be around $150
220 amp factory is around $180
Billet Mechman will run close to $500

To make it last it not the alternator it how you spin it,
Even a $500 mechman will not last a season if it is not setup correctly,
Click to expand...
What is your recommendation for the diameter of the alternator pulley to make it last?
 
FOG said:
What is your recommendation for the diameter of the alternator pulley to make it last?
Click to expand...
18k rpm is about the max for them. Divide 18k by your rev limiter for the optimum ratio. Figure out your crank pulley diameter, then divide it by the ratio to get the alternator pulley size.

But... If revving to 7,000rpm, you'd need at least a 2.9" pulley with the stock LS3 pulley (7.5").
 
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Rockwood said:
18k rpm is about the max for them. Divide 18k by your rev limiter for the optimum ratio. Figure out your crank pulley diameter, then divide it by the ratio to get the alternator pulley size.

But... If revving to 7,000rpm, you'd need at least a 2.9" pulley with the stock LS3 pulley (7.5").
Click to expand...
Good to know. Thanks for the feedback.
 
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