Voltage light on - battery not charging. Thoughts on batteries, alts, etc. (1 Viewer)

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So right after we did rear rotors/pads (CLEARLY the cause of this problem), the voltage light started coming on randomly and the scangauge showed that my battery voltage was quite low, even at high idle. Then weird stuff started happening, for example: Scangauge wouldn't turn on, extremely high idle, hard brake pedal, etc. I've been taught that "weird" symptoms are classic cases of a failing 12v battery, so I have a new one arriving tomorrow and the old one on a charger. I figured if the alt was the culprit, oh well, I'd accidentally have two batteries for my dual battery system.

So my thoughts are this - I think I may have jumped the gun ordering a new battery, and that I may have a failing alt. That's terrible, except for the fact that I wanted to upgrade the alternator to the 150A. I've perused the thread thoroughly regarding this and I have a few questions -

1) How hard is it to replace the alt on a non-rusty truck with good tools? I don't mind removing the battery box or whatnot. Shame there's no video on it.
2) Do I need to upgrade anything besides the alt? For example, alt cables, etc?
3) Exactly what alt from the Tundra do I need?
4) What are the possible downsides to doing this?

What are your thoughts, mud? Thanks.
 

2KCruiser

Everything 2KRacing, practically live here
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I think those are 2 separate belts, no need to loosen the AC belt.
 
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I've been thinking about this mod as well. What year tundra alternator will I be looking for anyway? And is it a plug n play job or a splice n dice?
 
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What factory grounds do I need to upgrade if I switch to the 150? Should 50 feet of 0 gauge be sufficient for rewiring from the alt to the battery?
 
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50ft?? Your 80 must be massive! Haha, 10ft would be enough.

Thanks! Welding cable, 4/0 gauge, is that what I need? All copper, keep it short? Not sure exactly what to do with the cable - the cables that go to the battery are wrapped in tape so I'm not sure what else is in that conduit.
 
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Whoa buddy a 4/0 gauge wire is 3/4" in diameter just the copper! You could likely use something much much smaller. I would bet the factory is less than 4G. There is a guy on mud that sells an upgraded cable set. I am on my phone or I would search for you, but you need to slow down a little bit. If you bought 50' of 4/0 (0000) You could power a neighborhood. haha.

Here is what 0000 wire looks like
DSCF0454.jpg
 
Joined
Jun 27, 2014
Messages
509
Whoa buddy a 4/0 gauge wire is 3/4" in diameter just the copper! You could likely use something much much smaller. I would bet the factory is less than 4G. There is a guy on mud that sells an upgraded cable set. I am on my phone or I would search for you, but you need to slow down a little bit. If you bought 50' of 4/0 (0000) You could power a neighborhood. haha.

Here is what 0000 wire looks like
DSCF0454.jpg


Yeah, I can be a little bit excitable. Noted - I'll stick with 4-6AWG. I'm actually going to use my stock harness for now - I'm only powering one battery and the distributor. Any risk in that?

A brief update - the old alt is out.

I first crushed and crumbled every important connector on my harness (they broke immediately), but I wasn't too upset about it. The one to the distributor cap doesn't seem to need the locking tab. The one that was in the alt was quite brittle. The bad news is that I destroyed it. The good news is that the pins I needed to extract from the connector popped right out and are ready to go into my new connector.

A few things to note - the top bolt (pivot bolt) is the only one you have to really lean on to get it started. Your tensioner bolt is best removed with a ratcheting wrench with a swivel head (like a gearwrench). It is not hard in the slightest, but it's a long bolt with a fine thread pitch so you'll be at it for awhile. At some point your belts will loosen sufficiently that you can gently pry them off with your finger and give yourself a little more room. Then you remove the final bolt, the lock bolt. Mine was finger-tight. Rock the alternator back and forth a bit and it'll start to swivel. Once the top pops free you're in for some real fun trying to figure out how to get it out. I managed to get it between the two hoses from the power steering reservoir.
 

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