Dual electric fans question.

[Mike_The_Grad]

Hey everyone, I'm currently waiting on my Old Air Products dual electric fan setup to show up anyday now. I read on their page that this set up requires a 70+ Amp. Alternator.
I am running a reman 63 Amp 10si single-wire alternator. My 72 c10 is Non-A/C, has a basic stereo in it (2-6" speakers, mini tweeters, no amp.) I have LED's in my side markers front and rear and in my gauge cluster, I also have the LED taillights and dome lamp. Sealed beam headlights with relay upgrades. And has been rewired with American Autowire Classic Update Series kit.

My question is, do I need to get a higher amp alternator? 7 amps doesn't seem to me all that much of a difference. I have my eye on a Tuff Stuff 80 Amp alternator in case its necessary.

Thoughts? Opinions? Experiences? Thanks.

[HO455]

You might be okay.... But what is most likely going to be the problem is stop and go traffic in hot weather. Your current alternator will not supply full current at idle. So when you are idling and the fans are both on cooling the truck the system will be using the battery to keep things running. The battery charge rate will always be slower than the discharge rate. Meaning if your idling for 5 minutes and driving for five minutes your battery voltage will slowly go lower. (This example generally holds true when your amp draw is above about 60% of full current capacity of your alternator.)
I've had stock unmodified vehicles in the winter time that only get driven on city streets with no highway driving, only being driven in the dark, with the wipers on, the headlights on, defroster on, radio on, the brake lights on more than 50% of the time, the electrical draw of the ECM, fuel injectors and fuel pumps the vehicle will end up with a dead battery in less than a month.
Having a voltmeter in the truck and checking to see if the battery voltage drops at full current load when the truck is idling is the only way to know for sure.

Link to more information. http://madelectrical.com/electricalt...witworks.shtml

[Andy4639]

I would be looking into a new 94amp alternator. The electrical section has a bunch of info on them. Mad electric has some very good info on their website as well. This thread should help you out.


http://67-72chevytrucks.com/vboard/s...d.php?t=737824

[scottofksu]

Could always do the CS144 swap... AAW sells a conversion pigtail that makes going from si to cs plug and play.

[Mike_The_Grad]

Thanks to you all for your input. I had a friend who is electrical smart explain to me the electrical system demand based on amperage vs. Available amperage of my alternator. I like how HO455 explained it and it makes sense. And I will look into the CS144 swap as another option.

[HO455]

Thank you sir!
If you are interested here is a link to my repair thread. Scroll to post 467. This is the I start of my conversion to a SC130 for my Burban.

https://67-72chevytrucks.com/vboard/...698377&page=19

[k2rm]

I have an Old Air Products dual fan setup and I am using a CS144 and I have no problems running both fans simultaneously at idle. However, I set it up so that one fan will come on at 190F and both fans turn on at 200F. It is very rare that the second fan needs to kick on so if you set it up in a similar way, your 10si will likely be fine.

[Mike_The_Grad]

Cool, HO455.
K2rm how do you like the old air setup? What sold me on it was that it is actually made for our trucks Vs. Something "universal" or "custom". I'm more about making sure my truck has no mechanical issues Vs. How shiny or clean it is. It's my daily driver and the only vehicle I own. So I need to make sure its reliable. I figured this setup is a good way to eliminate any chance of traffic on a hot day keeping me from enjoying the drive like everyone else.

I'm assuming you guys are running A/C in your trucks based on the higher amp alternators? No A/C in mine and no plans for it in the future. I found a Tuff Stuff 100 amp alternator that is a 10SI with a 12SI smooth back case. It has a v belt pulley and is one-wire capable. It would basically be a like-for-like swap for me. Thoughts?

[Mike_The_Grad]

A couple of pics.

[MARKDTN]

Another vote for a CS144 swap. I have that on my '83 with dual fans and it is rock steady.

[HO455]

As the saying goes information is power. And your looking for more power. I do like the MAD Electric guy. So here is a link for more 10 & 12SI knowledge to help with your decision. I have no information on the specific alternator you mentioned but you might make a thread asking about them in the electrical section.

http://madelectrical.com/electricaltech/delcoremy.shtml

[k2rm]

Originally Posted by Mike_The_Grad

Cool, HO455.
K2rm how do you like the old air setup?

It works well. This is the only electric fan setup I have put into the truck so I don't have anything to compare it to. It does fit nicely and it was easy to install. I put it in about 8 years ago and this one has two different speed fans. The low speed fan is fairly quiet and is the one that kicks on at 190F. The high speed fan is quite loud when it kicks on at 200F. It seems to move a lot of air. I have AC and a Holley HP MPFI system that controls when the fans kick on and off.

[70']

I am running dual electric fans in my 1970 with a 468 big block. When both fans kick on it really drains the electric system. I am running a 140 amp alternator from CVF Racing. They aren't that bad price wise at $140 shipped. well worth the money. One of the worst things you can do to any electrical component is running it on less volts/amps than it was designed to run on.