More Power! Alternator on Overdrive (1 Viewer)

[TeCKis300]

Following in the footsteps of @FrazzledHunter and his full 390A alternator upgrade:
Alternator upgrade - done! - https://forum.ih8mud.com/threads/alternator-upgrade-done.1329033/

What​

A smaller alternator overdrive pulley and matching belt to spin the OEM 180A alternator ~16% faster. Not necessarily to expand max output, but to add low rpm output support and longevity against added loads.
Stock pulley is 2.25". Overdrive pulley is 1.93".
Stock engine to alternator drive ratio is 3:1. Overdrive ratio is 3.65:1
Min alternator RPM of 2,000 (stock 1,650) at 550 engine idle
Max alternator RPM of 20,800 (stock 17,100) at 5,700 engine redline

How​

Purchase​

1. Overdrive pulley from M2kinc | Automotive Diagnostic,programing Tools. - http://www.m2kinc.com/ Likely a custom order.
2. Gates K080944 Micro-V 8G Serpentine Drive Belt - Amazon.com - https://www.amazon.com/gp/product/B001CIEFCI

Install​

Doing this job with alternator in situ is no joke and I wasn't able to remove the pulley. It's tricky to get enough leverage and bite on the 22m retaining nut, while countering by holding the pulley or 10mm shaft. Even after fabbing up a custom tool. I resorted to removing the alternator (2-4 bananas depending on skill and access tools). The job was probably only 2hrs total once I gave in to removing the alternator. Radiator left in place but that is potentially another option and approach to get a compact impact gun on the pulley nut. Undo brackets that hold the tranny cooling lines and power steering lines, and unbolt the sway bar (LX) to let it hang down. KDSS would make this trickier. Once I was able to rotate the alternator in the engine bay where I could hit the retaining nut squarely with an impact (DCF921B), it made quick work to remove the OE pulley and install the overdrive pulley. No countering necessary with an impact. Torque spec is 29 ft lbs but a couple ugga duggas from my calibrated impact

More detailed install instructions can be found in this thread

RTH: Alternator Suspect Voltage Output

I'm on a road trip right now and noticed my aux house battery that runs my fridge seems to not be fully charged. This is suspect as we drove 9 hrs yesterday and I would normally expect it to be fully charged. Looking at my starter battery voltage with the car is running, the voltage seems to...

forum.ih8mud.com

Alternator in situ. Not much working room

This custom 22mm socket tool was good, but I could not get the 10mm socket on the shaft to bite and counter with enough torque

Unmounted alternator positioned where I could get an impact socket squarely on the pulley nut from underneath.

Why​

I decided to pursue a milder path to overdrive the stock alternator for incrementally higher than stock power demands. Partially to help the alternator last longer against added loads. My original alternator failed at ~165k. Brushes looked good. Regulator likely wore out due to heat and loads, especially at idle where the alternator has to work its hardest with minimal cooling.

Key to this was FrazzledHunter work identifying a vender that could provide a smaller diameter overdrive pulley that was used in his full alternator upgrade. And also identifying a shorter accessory belt.

Taking a step back, my additional power demands are moderate considering that the OEM system provides some margin to power accessories. A good rule of thumb is not to exceed ~30% of the rated alternator output with additional loads. I have roughly 58A additional loads including: 1. Onboard Victron 18A DC-DC charger for house battery, 2. 10A trailer 7-pin DC-DC charger 3. 20A Anderson to trailer DC-DC charger 4. 10A in misc lights/radio/cell booster. Many of us upgrade the starter battery and it's good to recognize the battery itself can be an additional burden given some performance lead acids and AGMs can draw significantly more current to charge with their lower internal resistance and higher capacities.

Notably, alternators only output half of their rated current at idle. Combine this in the worst case-scenario on a hot day, heat soaked engine, started battery very drawn down, accessories in use, while in low speed crawling. A major part to "improving" alternator output and performance in my mind is to improve cooling under heavy loads at idle. The overdrive is as much to incrementally increase output (thereby decreasing load stress and heat generated), as it is to increase self cooling with more drive RPM.

This is an output graph for a typical 180A alternator. A ~25A output improvement. Less voltage sag at idle. More output support. Faster starter battery recovery even with loads on.

 

[TeCKis300]

Perhaps more interesting than the specific mod above is the vender involved and custom solutions they can provide - M2K / SBC
M2kinc | Automotive Diagnostic,programing Tools. - https://m2kinc.com/ SBC | Automotive Alternators - https://smartbatterycharger.net/
These guys are gearheads supporting all makes an models, but also Toyota enthusiasts supporting Land Cruiser around the world. Providing power solutions to the military and other major customers, from mild to wild. They have patient techs willing to talk through specific use cases and trades.

I was curious and inquired on some common overlanding mods and how they could support it. I was surprised by the solutions they could provide including:

Alternators with AGM Charging Profiles​

Yes, you read that right. I've harped on for years that AGMs aren't compatible with our stock alternator regulators setup for lead acid charging profiles which results in premature death to expensive batts. M2K / SBC has solutions to tailor regulator outputs for AGM.

Alternators for Lithium Charging​

They have solutions with external regulators on alternators that can direct charge lithiums!

More Robust Alternator Protections from Submerging​

We know the OEM alternator may die a quick death after fording water. While M2K / SBC doesn't build sealed alternators, they can supply more robust solutions for alternators that are better protected from such use cases.

 

[OregonLC]

Out of curiosity, have you ran into limits with the OEM alternator? I've thought about this, but even with depleted house battery, at 30A charging load it's only three hours to full (via RedArc BCDC), something easily achievable in overlanding drive cycles.

The instance where I could see this being needed is with a) high power aftermarket sound systems or b) massive charging loads from a YouTuber (cameras, laptops, etc.).

Rather than increased output, I'd be interested in the redundancy of a secondary alternator. A dead alternator on the trail could be a really bad day. Though with Toyota alternators this hasn't been a reported problem that needs a solution. I did opt for dual Alts in the Ram, however, for this reason.

 

[NoClue]

Great work. I'd love a brushless alternator with a higher charge output for an agm on my 16'.

 

[Moby]

Good stuff! Always appreciate your write ups @TeCKis300

 

[TeCKis300]

Out of curiosity, have you ran into limits with the OEM alternator? I've thought about this, but even with depleted house battery, at 30A charging load it's only three hours to full (via RedArc BCDC), something easily achievable in overlanding drive cycles.

The instance where I could see this being needed is with a) high power aftermarket sound systems or b) massive charging loads from a YouTuber (cameras, laptops, etc.).

Rather than increased output, I'd be interested in the redundancy of a secondary alternator. A dead alternator on the trail could be a really bad day. Though with Toyota alternators this hasn't been a reported problem that needs a solution. I did opt for dual Alts in the Ram, however, for this reason.

Yes and no. I believe my original alternator died a bit premature at 165k miles. Teardown showed that bearings were great, brushes had more life, commutator was fine. The failure mode was one of reduced output to where the starter battery voltage seemed to sag and no longer be topped off. My DC-DC chargers were not charging the aux LiFePO4 that supports my fridge.

Coming from the RV and vanlife forums, often a failure mode is too much load on the alternators causing them to run hot and burn out. Larger battery banks put an extended load where the alternators have to work hard for longer durations really heat soaking them. Particularly at idle where there is limited load support and elevated temps due to stress on the alternator. As alternators get hot, their output potential further falls, created a negative feedback loop.

If I had to guess, my failure was probably the regulator from excess heat and loads over time. I'm often camping, overlanding, and off-road crawling. A mix between deep battery draws in camp, and sometimes slow crawling and wheeling during the day. In summer with lots of heat, fridge, and other accessories running. Another thing I do is to idle the car at least once in 115F summer heat while powering multiple DC-DC chargers, including one to augment travel trailer A/C use. I've sized these all as moderate loads and I don't think it was due to a single overload event, but harder use over time degrading the alternator?

Not a bad idea of redundancy with a second alternator that is mounted high in the engine bay.

 

[BadReligion]

I had no idea you could buy a 390A exact fit high output alternator (made from Denso components) for the 3UR. There is probably a good chance you could run a Premier onboard welder off of it too.

 

[OregonLC]

Yes and no. I believe my original alternator died a bit premature at 165k miles. Teardown showed that bearings were great, brushes had more life, commutator was fine. The failure mode was one of reduced output to where the starter battery voltage seemed to sag and no longer be topped off. My DC-DC chargers were not charging the aux LiFePO4 that supports my fridge.

Coming from the RV and vanlife forums, often a failure mode is too much load on the alternators causing them to run hot and burn out. Larger battery banks put an extended load where the alternators have to work hard for longer durations really heat soaking them. Particularly at idle where there is limited load support and elevated temps due to stress on the alternator. As alternators get hot, their output potential further falls, created a negative feedback loop.

If I had to guess, my failure was probably the regulator from excess heat and loads over time. I'm often camping, overlanding, and off-road crawling. A mix between deep battery draws in camp, and sometimes slow crawling and wheeling during the day. In summer with lots of heat, fridge, and other accessories running. Another thing I do is to idle the car at least once in 115F summer heat while powering multiple DC-DC chargers, including one to augment travel trailer A/C use. I've sized these all as moderate loads and I don't think it was due to a single overload event, but harder use over time degrading the alternator?

Not a bad idea of redundancy with a second alternator that is mounted high in the engine bay.

With this theory, wouldn't an smaller (overdrive) pulley aggravate the problem? If load related heat is the suspect, then wouldn't more output just create that much more heat?

 

[FrazzledHunter]

I had no idea you could buy a 390A exact fit high output alternator (made from Denso components) for the 3UR. There is probably a good chance you could run a Premier onboard welder off of it too.

Yes you can! Mine's been working great so far.

While you can drop in a higher amperage alternator (with or without a smaller pulley & the requisite shorter serpentine belt) you have to upgrade the OEM wiring to actually use it.

That upgrade consists of upgrading or augmenting the alternator to battery, motor to frame and battery to frame connections. This upgrade is referred to as the "Big 3" and is done frequently by those doing alternator upgrades for huge audio amps. Each vehicle is different and shops that do this kind of work have a map of exactly what they do for each install.

 

[BadReligion]

Very cool. Makes sense about the wire upgrades. Are you running the Micro or Standard?

 

[FrazzledHunter]

Very cool. Makes sense about the wire upgrades. Are you running the Micro or Standard?

Do you mean the pulley? If so then I'm using the 2 in. (smaller than OEM) pulley. According to the published performance curve this should offer almost 200A and sufficient alternator RPM's for alternator cooling at engine idle of 600 RPM.

 

[BadReligion]

Do you mean the pulley? If so then I'm using the 2 in. (smaller than OEM) pulley. According to the published performance curve this should offer almost 200A and sufficient alternator RPM's for alternator cooling at engine idle of 600 RPM.

Sorry. I meant the welder. With the "Standard" Premier having the 120v outlet. The Micro does not.

 

[TeCKis300]

With this theory, wouldn't an smaller (overdrive) pulley aggravate the problem? If load related heat is the suspect, then wouldn't more output just create that much more heat?

Possible but it's not as simple as output equals heat generated. There's a concept of load / power factor, meaning more heat is generated when an alternator is working hard. When it's working hard against a load it can't meet, voltage will also fall requiring even more amperage which is another factor generating heat. More RPM provides more potential to meet demands with a lower power factor, so it's less stressed with less heat generated. Then there's the internal fan which provides more cooling at higher RPMs.

Interestingly, at some point, too low of a power factor and reactive lagging load on the rotor creates heat too.

If there is a EE engineer in the room, would love any additional details (or corrections!).

 

[gluaisrothai]

Possible but it's not as simple as output equals heat generated. There's a concept of load / power factor, meaning more heat is generated when an alternator is working hard. When it's working hard against a load it can't meet, voltage will also fall requiring even more amperage which is another factor generating heat. More RPM provides more potential to meet demands with a lower power factor, so it's less stressed with less heat generated. Then there's the internal fan which provides more cooling at higher RPMs.

Interestingly, at some point, too low of a power factor and reactive lagging load on the rotor creates heat too.

If there is a EE engineer in the room, would love any additional details (or corrections!).

Not an EE but part of the answer is that regulator adjusts field current to the alternator to achieve the target output voltage. This is the current sent into the rotor via the brushes to produce the magnetic field which creates the alternating current in the stator which is then rectified to DC. At lower RPM a higher field current is needed to achieve the target output voltage therefore more heat is generated in the rotor…and that’s also when the alternator cooling air is the least.

 

[TeCKis300]

Not an EE but part of the answer is that regulator adjusts field current to the alternator to achieve the target output voltage. This is the current sent into the rotor via the brushes to produce the magnetic field which creates the alternating current in the stator which is then rectified to DC. At lower RPM a higher field current is needed to achieve the target output voltage therefore more heat is generated in the rotor…and that’s also when the alternator cooling air is the least.

Good input and appreciate it described in a way that's easy to understand!

 

[Fisher23]

1. Overdrive pulley from M2kinc | Automotive Diagnostic,programing Tools. - http://www.m2kinc.com/ Likely a custom order.

Nice write up!

Do you have the part number of the pully?