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Discussion Starter · #1 ·
Does anyone happen to know the exact and/or approximate length of the three cables needed for the Big 3 upgrade on a 1998 Astro RWD? Reason I ask is I would like to cut and pre-assemble the cables for a mechanic friend who has offered to R&R them for me :)
 

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Common Sense + Critical Thinking
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Generally not needed, at all, but to each their own. Have you read though the big3 thread or tried search?
 

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Aloha AstroWill. Yep read everything on the forum regarding the procedure. Having some corrosion and cable sheath damage issues. Just figured it was better to start fresh with all new wire and cable. Will also be adding an additional 100AH house battery so I'm anticipating a HO Alternator upgrade this spring.
 

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In that case, upgrading the wiring, esp to the alternator will definitely help! Once you upgrade your alternator and add batteries, it can really pull a lot from the alternator. Of course you don't have to route it the same way as factory either which would change the length of the cable. Probably best to measure it on your own, I like using some non-stretching marking line to route and measure my wires.
 

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2004 Safari RWD, 2002 Astro AWD
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To under stand you guys correctly.
If I install a high amp alternator, AD244 220amp version or so, then I should up grade the alternator cable to a larger size to the battery?
What wire gauge do you recommend be installed.
 

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2000 Lifted 4x4 Astro 92 V8-350 Shorty
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To under stand you guys correctly.
If I install a high amp alternator, AD244 220amp version or so, then I should up grade the alternator cable to a larger size to the battery?
What wire gauge do you recommend be installed.
"Should"?
It may really depend on your actual current amperage needs.

Just to put it in perspective.. I upgraded to AD244 HO alternator. I'm running stock factory wiring... and find it sufficient, still getting the benefits of the higher output. Don't get me wrong, I believe in large gauge wiring.. but it's not an absolute requirement if you use the AD244 style alternator. Alternators don't "push" current, they "supply" current based on load demands.

I have NO plan to change my wiring.. my HO system is working fantastic for me now.
But I also encourage it if you feel the need and desire.
Just be certain your connectors are rock solid.
 
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If I install a high amp alternator, AD244 220amp version or so, then I should up grade the alternator cable to a larger size to the battery?
Should? Probably and it really shouldn't be that big of a deal, it's only a few feet of wire if you route and connect it like stock. Now that is going to the starter, which is how it's set up stock, the wire from the battery to the starter will already handle it. If you are going directly from the alternator to the battery instead, you will need more wire.

Do you HAVE to? Possibly not, as mentioned above the alternator isn't 'pushing' amperage but simply making it available. Lets say you have a standard running load of 70amps and your stock alternator is normally capable of putting out 100amps, your still only pulling 70amps from that alternator. Simple.

Now lets say you upgrade to an alternator that can provide 200amps, under normal conditions your standard running load is still only pulling 70amps from that alternator. Now if you start adding loads, you left a light on or left your laptop charging and now your battery is half dead, the battery will pull significantly more from the alternator once the engine is running. Adding lead acid house batteries that you discharge to 50% or lithium batteries that you discharge to 5% will pull significantly more until charged, more batteries and the load becomes larger. Jump starting someones dead vehicle, will pull more than your standard running load. Added electric fans, more. Have a wire rub the insulation off and create a path to ground, the alternator is going to supply what it can until it can't anymore, is the wire going to handle it until it gives up?

So yes, under normal running conditions you could probably get away with it. However, there is a reason that vehicles with larger alternators run larger wires from the factory, and there is a reason that the alternator manufacturers have recommended wire sizes in their installation manuals, and yes there are valid reasons that we use fuses and fusible links to protect our wires so they don't catch on fire :)


With that said, it's always your decision, go with what you feel. I have been in homes where a 14awg circuit is double tapped to a 30amp breaker before, running a heater, against code = yes, complete fire hazard = yes, like that for 15yrs = yes, dumb AF = YES! Or the christmas light extension cord ran through the wall, or the dryer circuit tapped into the side of the range receptacle, could go on and on.
 

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If you are actually planning on using all of the available amperage of the alternator, "0" gauge copper is rated for 245 amps. So basically you would need arc welder cable for your power needs. Plus you better have damn good connectors if using that much juice. The factory wiring is usually 10ga for 120 amp alternators and that rating is for between 50-75% load.

My question is - What in the world would you need that much power for? If you are planning on a few inverters and 1,000 watt lights and amplifiers, that's another story. Other then that, it's wasted potential, and money.

Plus, you can upgrade the cable from the alternator to the battery, that's fine. But with that much current draw in your electrical system, you had better upgrade the wiring from the battery to whatever distribution point you are planning on using.
 

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Yep,yep,nope and yep, LOL,whatever.
Just some basics. The bigger cable is generally needed for the load, not to charge the battery. That is why it is run to inverters, and on long runs, you can see some fine installations on the net, in "audio race cars". BUT, the drawback of a lot of vehicles, can be the wire from the alternator to the battery, a lot of GM's especially, go to a junction block on firewall, down to starter, then batt. is charged by the big cable from starter to batt. Generally undersized for bigger than stock alternators, BUT not always, depending on your driving conditions, and electricity usage. A lot of times, just the same size cable run straight to battery is fine. A alternator is for the load, charging is secondary. They are not meant to charge a dead battery, besides, high amps into a dead/very low battery is bad, and dangerous, as now you are creating a bomb. Generally battery charge should never go over 20-30 amps. remember all those burnt up hoods on 80-90's chevys,? And a melted lump of alternator under the hood? Or seized alternators? This is from jump starting a dead battery, and driving it to charge! Unfortunately,I have seen lots of "mechanics:" do this,also. Good upfitters always split things off, with the wiring.
Also, over the years, I never get "technical" replacing even customers cables, as many refuse to purchace the factory items, because they come as a harness assembly, can be quite expensive, just run it along outside, wire tyes, snip ends off of old cable.
I could go on, but that is just some basic stuff. The average person will never need a super hi output alternator, or the occasions are so rare, not worth it.
 

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One of the BIGGEST benefits (for me) of the AD244 HO alternator is a much stronger output at idle as well. My system pulling a heavy load (A/C, dual fans, engine fan, electronics, fuel pump, head lights and fog lights, etc etc) would always dip well below 12v sitting at traffic lights. Now my system stays ROCK SOLID at 14v, even at idle.
 

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Discussion Starter · #14 ·
What a great interaction. Love this site. I think the only thing left out is voltage drop is equal to I/R
Couldn't agree more Tungtide. Awesome input - especially for people, like me, who do not have an extensive automotive or mechanical background. This is the best forum on the planet for anyone immersed in exploring the vast territory of possibilities in AstroSafari land.
 

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1992 Astro - Silver / Gray / 4 Wheels
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Really... it is so nice to read a thread like this.
I don't do 'Likes n' Smilies and stuff.

But I do like to thank members... like Will, Bird, music, ehb, bob.

Thanks
 
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