Sign of Failing Alternator? (1 Viewer)

[GTV]

A few days ago my battery light came on and the voltage on the gauge was very low, just over 9v. Since I was in the middle of nowhere I decided to drive on to the next town and sort it out there. Luckily after about only 10-15 minutes the needle on the gauge came up to normal and the light went off. I drove straight to an Autozone where they performed a charging system test, the alternator and the battery tested out perfect at 100%. I've had zero issues since then.

I'm wondering if this is a sign of a failing alternator. @2001LC do you remember if you replaced the alternator when you did the engine swap?

Naturally I'm looking at an alternator upgrade that is a direct swap for my '07 and doesn't sacrifice reliability, is there such a thing? Are they actually anything special or are they just a standard alternator with a smaller pulley? Specifically looking at this one but I'm open to suggestions. Thanks!

 

[suprarx7nut]

Definitely sounds like failing alternator. I've had a few on the 100, lol.

They can come and go towards the end. Get it swapped ASAP, IMO.

If you're constantly charging an aux battery and/or a massive stereo and don't have solar, then a big alt might be a good call. Otherwise, I'd stick with genuine Toyota reman.

 

[GTV]

Definitely sounds like failing alternator. I've had a few on the 100, lol.

They can come and go towards the end. Get it swapped ASAP, IMO.

If you're constantly charging an aux battery and/or a massive stereo and don't have solar, then a big alt might be a good call. Otherwise, I'd stick with genuine Toyota reman.

I’m due for a timing belt as well so that would be a great opportunity.

I’m not charging anything extra at the moment but that’s going to change soon as I’m in the planning stages for a small 30L fridge, etc. From the research I’ve done so far it looks like the Sequoia 150a alternator is plug and play and a smaller pulley would help charging and cooling at lower rpm’s. So I’m kinda leaning that simple but effective way. Automotive electrics is a whole new world to me and I feel like my head is about to explode

 

[suprarx7nut]

I’m due for a timing belt as well so that would be a great opportunity.

I’m not charging anything extra at the moment but that’s going to change soon as I’m in the planning stages for a small 30L fridge, etc. From the research I’ve done so far it looks like the Sequoia 150a alternator is plug and play and a smaller pulley would help charging and cooling at lower rpm’s. So I’m kinda leaning that simple but effective way. Automotive electrics is a whole new world to me and I feel like my head is about to explode

A small 30l fridge should consume almost nothing. I would not get an aftermarket "upgrade" for that.

For reference:

Stock alternator (late year LX): 1,820 W

Small fridge: 40W
Cell Phone Charger: 20W
Aux battery plugged into cigarette lighter: 80W

Added demand: 140W. 7.7% of output.


My old 99 had a 1500W (peak power) stereo.
Unusually powerful Eco Flow alternator charger is 800W

Added demand: 2300W. 126% added demand. That's when you need those huge alternators. The one you linked is ~3400W. Great for huge draws. Total overkill for anything less than a massive stereo and/or EcoFlow alt charger.

 

[hoser]

I'm an OE guy but cost aside, I would choose DC Power (NEW) over OE Remanufactured. The core internals are new Denso. For me, most important would be hot idle output performance. Their 180A alternator produces 120A at 200 degrees F, at idle. ~180A at 2666 RPM. $469.

Product Result

Whether you’re into racing, off-roading, RVing, or have a 10,000 watt stereo system in your daily driver, you’ve come to the right place. DC Power Engineering Inc. alternators are engineered from the ground up for those that demand the very best. Engineering is more than a word to us – it’s our...

www.dcpowerinc.com

 

[GTV]

A small 30l fridge should consume almost nothing. I would not get an aftermarket "upgrade" for that.

For reference:

Stock alternator (late year LX): 1,820 W

Small fridge: 40W
Cell Phone Charger: 20W
Aux battery plugged into cigarette lighter: 80W

Added demand: 140W. 7.7% of output.


My old 99 had a 1500W (peak power) stereo.
Unusually powerful Eco Flow alternator charger is 800W

Added demand: 2300W. 126% added demand. That's when you need those huge alternators. The one you linked is ~3400W. Great for huge draws. Total overkill for anything less than a massive stereo and/or EcoFlow alt charger.

Thank you for the explanation!
The fridge I'm planning on using can be seen here. I've been seeing different ways power consumption is measured which makes this more confusing to calculate. I have yet to chose a power station but it will likely be pretty small due to my basic needs and space limitations. I've ordered this battery monitor so I can keep a closer eye on things. My starter battery is pushing 7 years old, I'm planning on making the jump to lithium once my current one is done.

 

[GTV]

I'm an OE guy but cost aside, I would choose DC Power (NEW) over OE Remanufactured. The core internals are new Denso. For me, most important would be hot idle output performance. Their 180A alternator produces 120A at 200 degrees F, at idle. ~180A at 2666 RPM. $469.

Product Result

Whether you’re into racing, off-roading, RVing, or have a 10,000 watt stereo system in your daily driver, you’ve come to the right place. DC Power Engineering Inc. alternators are engineered from the ground up for those that demand the very best. Engineering is more than a word to us – it’s our...

www.dcpowerinc.com

That does look pretty cool. Reman Sequoia 150a alt is $250 + $75 core (via McGeorge) so that's an extra 30a for about $145. Do you happen to know what the idle specs are on the 150a?

 

[suprarx7nut]

Thank you for the explanation!
The fridge I'm planning on using can be seen here. I've been seeing different ways power consumption is measured which makes this more confusing to calculate. I have yet to chose a power station but it will likely be pretty small due to my basic needs and space limitations. I've ordered this battery monitor so I can keep a closer eye on things. My starter battery is pushing 7 years old, I'm planning on making the jump to lithium once my current one is done.

Looks like 60W max. I bet typical draw is ~40W. That's what we see with the Dometic CD30. Similar compressor.

I'm a big fan of battery tech and lithium, but I wouldn't do a lithium starter battery. Regular lead acid or AGM is good. Lithium aux battery? Absolutely. Starter battery? Nah.

Can You Use a Lithium Battery to Start a Car?

Can lithium batteries be used to start a car? Batteries Plus explains the pros, cons and what to know about starting batteries.

www.batteriesplus.com

 

[2001LC]

A few days ago my battery light came on and the voltage on the gauge was very low, just over 9v. Since I was in the middle of nowhere I decided to drive on to the next town and sort it out there. Luckily after about only 10-15 minutes the needle on the gauge came up to normal and the light went off. I drove straight to an Autozone where they performed a charging system test, the alternator and the battery tested out perfect at 100%. I've had zero issues since then.

I'm wondering if this is a sign of a failing alternator. @2001LC do you remember if you replaced the alternator when you did the engine swap?

Naturally I'm looking at an alternator upgrade that is a direct swap for my '07 and doesn't sacrifice reliability, is there such a thing? Are they actually anything special or are they just a standard alternator with a smaller pulley? Specifically looking at this one but I'm open to suggestions. Thanks!


View attachment 3736698

I did not replace the alternator.
It does sound like a failing alternator.

 

[hoser]

That does look pretty cool. Reman Sequoia 150a alt is $250 + $75 core (via McGeorge) so that's an extra 30a for about $145. Do you happen to know what the idle specs are on the 150a?

No, I don't know the Sequoia output specs and I haven't seen it published anywhere. Like @suprarx7nut said, your electrical demands aren't really high, and a stock alternator is probably fine. However, if you want quick charging of your aux battery, an uprated alternator can be useful. It can help with winching too.

The sequoia 150A alternator is Toyotas idea for towing/charging the trailer batteries. But that was almost 20 years ago with Lead Acid/AGM batteries. Probably still adequate by today but Lithium batteries can accept a faster charge and hence a higher output alternator might be useful. Fast charging is not the best for the battery but you can select the rate with some smart DC-DC chargers and choose base on your circumstances.

 

[GTV]

Looks like 60W max. I bet typical draw is ~40W. That's what we see with the Dometic CD30. Similar compressor.

View attachment 3737501

I'm a big fan of battery tech and lithium, but I wouldn't do a lithium starter battery. Regular lead acid or AGM is good. Lithium aux battery? Absolutely. Starter battery? Nah.

Can You Use a Lithium Battery to Start a Car?

Can lithium batteries be used to start a car? Batteries Plus explains the pros, cons and what to know about starting batteries.

www.batteriesplus.com

I'm a weight weenie and the idea of loosing 30-ish lbs from the heaviest corner of the vehicle is very appealing to me (yes, even in a 3 ton vehicle). I've seen them used successfully in enough applications that I'm willing to give it a try.

No, I don't know the Sequoia output specs and I haven't seen it published anywhere. Like @suprarx7nut said, your electrical demands aren't really high, and a stock alternator is probably fine. However, if you want quick charging of your aux battery, an uprated alternator can be useful. It can help with winching too.

The sequoia 150A alternator is Toyotas idea for towing/charging the trailer batteries. But that was almost 20 years ago with Lead Acid/AGM batteries. Probably still adequate by today but Lithium batteries can accept a faster charge and hence a higher output alternator might be useful. Fast charging is not the best for the battery but you can select the rate with some smart DC-DC chargers and choose base on your circumstances.

Great points. I am planning for a winch and a dual ARB as well.

Thanks to both of you for the advice, I feel like I still have a lot to learn.

 

[aphex2k]

Just had a similar issue.
Battery light was coming on and going off, intermittently.

Mechanic did battery and alt test. Alt passed, battery flagged as 53% health.

I swapped out a new battery. 2 days later the light comes on, goes off.

Mechanic did another check. Said +ve terminal on alt had a loose nut. Power was arcing and nut starting to melt. Replaced and all good.

 

[hoser]

I'm a weight weenie and the idea of loosing 30-ish lbs from the heaviest corner of the vehicle is very appealing to me (yes, even in a 3 ton vehicle). I've seen them used successfully in enough applications that I'm willing to give it a try.

The two applications LiFePO4 batteries are known not to be good are winching and freezing temperatures..... though some manufacturers claim they can. The factory charging system is also not ideal for Lithium batteries.

 

[BnvS]

Shameless self promo.. if you are indeed upgrading your alternator then upgrade your grounding wires-Alternator cable as well. I sell Big 3 grounding kit with Alternator cable as well. This would work better when you are using your high output accessories such as Winches or similar..

 

[GTV]

The two applications LiFePO4 batteries are known not to be good are winching and freezing temperatures..... though some manufacturers claim they can. The factory charging system is also not ideal for Lithium batteries.

To me it feels like the lead acid companies are threatened and pushing the idea that lithium is bad. The only way I’ll know if it will work for me is to try it out myself. I just moved back to the southwest so I’m not that worried about severe cold, I’m also not a “wheeler” so winching will be rare. I’ll have a battery monitor so at least I’ll have data to go along with my experience. So we’ll see.

Thanks for the DC link, I think that 180a will be a good fit and future proof me if/when things get changed up.

 

[Saintbeau]

Be aware that these systems are very sensitive and I would clean and re do my terminals before replacing battery and or alternator. Speaking from experience. Not a bad time to check grounds for corrosion as well.

 

[SeekerJAE]

There was another thread that I cannot now find, but here seems a good place to add my experience with a recent alternator replacement. (99 LC100 430,000 miles - 3rd owner)

I replaced the alternator in February ‘24 with OEM reman (27060-50260-84), and although I bought a fresh pigtail off eBay, I didn’t install the fresh plug because mine seemed fine. Plus I don’t like playing with wiring if I don’t have to.

Sometime in the nine months since, I noticed that the AC started blowing either max cold or max heat when anything but the max cold setting was used on the AC Temp dial. I thought this was unrelated.

However, after nine months, the LC left my daughter stranded with a dead battery. I was able to jump it and run to O’Reilly for a system check which said bad voltage regulator. A little steamed because of the time it took to replace it the first time, I ordered another of the same unit.

This Saturday I swapped it out, and on Saturday night I had to go rescue my daughter again. Only this time it would not jump successfully. So I had it towed home.

So I spent the time to dig back in and found that the plug was loose on the back of the alternator. No a mount of pressure would get it to seat properly, so I went ahead and swapped in the new pig tail plug that I had on hand.

Plugged it in, reassembled everything and suddenly it was measuring 14.5 volts with the multimeter. Hooray!

Now the icing on the cake seems to be that my AC max hot/cold A/C demon seems to be gone too.

By the way once I had the old plug cut out, could see clearly that the plug problem was just a bunch of old gunk deep in the oval groove around the connector area. Doh… I could have just cleaned it out if I could have seen up in there to notice that in the first place.

At least now I have a spare 100 amp OEM unit. I am pretty certain that this spare unit didn’t really fail, that my issue was an unseated plug all along.

I hope this helps someone out there.

 

[GTV]

I got the DC Power 180a alternator in. The stud on the alternator is larger than factory at 8mm so I had to drill out the charge cable to 5/16" to fit.

I chickened out on the lithium battery upgrade. I have a feeling that the technology has been around long enough that there might be a second generation coming soon, and hopefully at a lower price.