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Inexpensive alternator Regulator Modification
#1
This link describes how to raise the charging voltage and lower the charging voltage again if you need to push charge into the house batteries and then want to float charge them. It even talks about doing a mini equalization or equalization charge. It says basically what is needed and what amperage and ttype of diode might work best. Seems to make sense on the surface. I have not tried it. Just passing along a interesting website. 
 For high charging rate I’d want to go over the entire charging system for weak links as mentioned in the excellent Alternator Charging thread on this forum. 
http://www.smartgauge.co.uk/alt_mod.html
  How difficult is it to open a alternator and modify the regulator?. They don’t describe that part. Does not look like there is much space in them. 
 I stumbled onto a roll of 3M Glass Cloth Electrical Tape that sets at high temperatures. Maybe inside an alternator would be a good place to try.Is there anything else that should be checkedor modified when the alternator is apart?
 Also would this alternator regulator modification conflict with the ECU or ECM? On newer vehicles??  
  I plan on opening up a few alternators and tinkering with them so any suggestions are welcome. Thanks
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#2
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That's a great hack! I have a diesel ambo with a 250 amp altonarer  no computer but it has a digital volt & amp meter & this would be perfect. it charges at 14.22 volts & takes 15 amps to rum with no lights on. Thanks!
"If a law is unjust, a man is not only right to disobey it, he is obligated to do so." - Thomas Jefferson
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#3
I used to rebuild these after high school & they put out 3 phase AC then convert it to DC sng phase DC.
"If a law is unjust, a man is not only right to disobey it, he is obligated to do so." - Thomas Jefferson
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#4
That modification, adding diodes, fools the existing regulator into putting out more volts.  If your alternator field current is controlled by the engine computer you have to fool that.  The engine computer sees the battery voltage and adjusts the field current like alternator regulators used to.  The computer makes it a bit smarter.  If you pull on the power steering at low rpm the computer can stop the alternator, turn off the ac compressor and increase the idle speed so it doesn't stall.  

My 1999 Ford Windstar has an engine computer controlled alternator.
Say good night, Dick.
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#5
(03-16-2019, 08:03 AM)Trebor English Wrote: That modification, adding diodes, fools the existing regulator into putting out more volts.  If your alternator field current is controlled by the engine computer you have to fool that.  The engine computer sees the battery voltage and adjusts the field current like alternator regulators used to.  The computer makes it a bit smarter.  If you pull on the power steering at low rpm the computer can stop the alternator, turn off the ac compressor and increase the idle speed so it doesn't stall.  

My 1999 Ford Windstar has an engine computer controlled alternator.

Ok, maybe this modification is better on earlier non engine computer systems. For newer systems if I remember correctly Sternwake placed a resistor in the ECU, a potentiometer on the dashboard, and ??  The modification I linked only switches the voltage up and down by increments dictated by the diodes and current? I like the potentiometer version for it can be adjusted to 16 volts sometimes. I’m not confident to take apart my van any time soon todo this improvement.
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#6
(03-16-2019, 05:28 AM)Gr8ful Wrote: That's a great hack! I have a diesel ambo with a 250 amp altonarer  no computer but it has a digital volt & amp meter & this would be perfect. it charges at 14.22 volts & takes 15 amps to rum with no lights on. Thanks!

Wow. That’s some major juice power. I’ve heard about ambulance systems. Some come with a inverter system also?  Is your system working as you would like?
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#7
My 89 dodge employs an externally regulated alternator, and the voltage regulator is inside the engine computer.

This stock regulator would choose 14.9v on start up each time, and after a period of time would revert to 13.7v. Occassionally, for no cause i could determine, it would choot back upto 14.9v. There were some times it would decide that 13.9 14.1, or 14.7v were desirable, but again I could figure no logic as to when and why it decided upon these different voltages.

It irritated the piss out of me kowing my battery was 505 charged and only accepting 12 amps at 13.7v when it would ba accepting 45+ amps at 14.7v.

One online outfit came up with a system for computer regulated mopars whos ECM's VR had failed. The trick is to use a 10mOhm resistor inline on the wires which usually attach to the field terminas on the externally regulated alternator. Without this resistor to trick the computer into thinking it is still attached to teh alternator, it will illuminate the check engine light, and instead of reading the MAP TPS o2 and some other sensors to figure out air fuel mixture and spark timing, will revert to a limp home mode. I can feel the engine get sluggish under their foot and MPGS take a nosedive when the check engine light comes on.

I used a transpo540HD voltage regulator, i think this was designed for ford applications in teh mid 80's. It has a potentiometer inside to adjust the voltage. i snipped the legs to this potted potentiometer and soldered wires to the legs, and ran these wires to a 10 turn potentiometer on my dashboard, next to my voltmeters and ammeter.

it is quite amusing and informative to have 106 amps available ( at 2600+ rpm) to recharge my battery, and to see just mow many more amps flow at 14.7v compared to 13.7.
My alternator is rated at 120 amps and can make this, but 12.2 amps are required just to run the ignition and fuel pump. Lights and blower motor and other loads all take off what can be fed to the battery.

I have not modified other vehicles voltage regulation. I would be wary of doing so on many models.

On mine, if I allow 14.8v to be held for 30 seconds, when teh voltage regulator in my engine computer would otherwise be seeking 13.7v, the check engine light comes on. So basically i need to keep voltage @ 14.7v or under, or I have to reset my computer the next time the engine is off. the CEL will go off on its own the next start but the ECM still needs to be reset.

So I could not perform an EQ charge without sacrificing fuel and driveability. Also 16.2v can be absuive to some items and when i had a flooded battery requiring EQ charges i would turn a switch and use my other battery to power all loads.

Now I have no other battery, just a single AGM, and I basicaly choose 14.7v anytime the battery is undercharged, and 13.7 when it is.

i will goto 13.9 or 14v at night with lights and blower motor on. it seems when there are DC loads on a charging battery, that it can very slightly discharge even at float voltages.

My 120 amp alternator can only make 50 amps at hot idle. So idling at night with lights and blower motor on high(~33 amps of load) and the 8.2 amps required to run the engine, there is not much left over for battery charging, and if I am also using the stereo and my fridge is running, I have seen my battery have to provide what the alternator cannot.

These are the only times I would benefit from a higher output alternator, but honestly I do not spend much time driving at night, idling at red lights with a well depleted battery so it is almost a complete non issue.

What is an issue idling with a maxed out alternator, is how hot it gets. My temperature data shows a maxed out alternator under 25mph gets in the 200f range all too quickly, but at 65mph maxed out with all possible DC loads turned on, and well depleted battery, 139.5 F is the highest I have seen, at least the stator where my K type thermocouple is adhered. I am sure the rectifier plate is hotter but at this point can only guess as to how much.

I've no experience rebuilding or modifying alternators, but would love to upgrade diodes and heatsinking inside one, one day.

My Alternator is a lifetime warranty unit I bought at Kragen Auto parts in 2004. I had used that warranty often esecially before i got solar in 2007, and the last time was 2015 and Oreilly's simply handed me a new box when I handed them my old alternator. No money exchanged. My incentives for alternator upgradings are therefor low.

What is nice about my regulator modification is if My alternator is maxed out, i can simply dial down the voltage and the less difference between what the battery is at and what the regulator is asking for, the lss amperage the laternator has to make. Also My engine uses Dual V belts on the alternator. These are supposed to be matched belts, but no matter what i did one or the other belt would be too tight and induce annoying harmonics. Solution, since My AC compressor is just a pulley, was to run just one belt. But if damp and cold then this single v belt will start slipping and squealing at higher amperages. Solution, spin the potentiometer CCW until it stops squealing and then CW as the belt dries out and warms up.

Getting the alternator to rapidly recharge house batteries via voltage manipulation is certainly possible, but not always easy to do. I'd be fearful or trying on some newer vehicles and likely go with one of the Dc to DC converter options, if I employed a separate house battery, which i could and have done, but no longer do.

As it is I very much prefer to manually control the alternator, but really I want manual control of voltage on all my charging sources, and have it , and thus I can achieve excellent battery longevity.
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#8
(03-16-2019, 09:33 AM)Roadtripp Wrote:
(03-16-2019, 05:28 AM)Gr8ful Wrote: That's a great hack! I have a diesel ambo with a 250 amp altonarer  no computer but it has a digital volt & amp meter & this would be perfect. it charges at 14.22 volts & takes 15 amps to rum with no lights on. Thanks!

Wow. That’s some major juice power. I’ve heard about ambulance systems. Some come with a inverter system also?  Is your system working as you would like?
It wotks Great! I bought it last year, It's the best diesl Ford ever used,7.3 IDI, best yeat to own 1993, no computer, no rust, 80,000 miles, new tires, altonator, serpentine belt & 2 new batteries last year. Looks, runs, drives like a year or 2 old. No sticksers, 2nd or spare to a small firehouse in the suberbs. $2000. 
https://autowise.com/ford-diesel-engine-history/  Later is Better: If you have a choice, select the newest-model Ford IDI you can find, with the ’93 to ’94 years being best. You’ll get a better glow plug controller (D), serpentine belt system, and the turbo engine comes with stronger connecting rods. The 7.3L is desired more than the 6.9L because it has larger, ½-inch head bolts instead of 7⁄16-inch versions. Power everything, front & rear heat/air, everthing works. I Love the Ambo!
"If a law is unjust, a man is not only right to disobey it, he is obligated to do so." - Thomas Jefferson
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#9
My 1998 shuttle bus has the 7.3 turbo. Great motor...well except the one that in it..lol. Mine has the higher amp alternator too. The regulator looks like a small stereo amp that is inside the cab. I have seen models/yr buses that came with dual alternators. Customizing some brackets to the engine and installing a 2nd alternator might be easier. idk. Then could prob somehow switch one off and on as needed when engine is running. Then just get a longer belt. Just an idea. I'm not much of an electrical person.
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#10
Redundancy of two alternators is comforting, and with the second alternator dedicated to house battrery bank and the first dedicated to the original batteries, one need not worry about a solenoid or isolator.
Since my AC compressor is just a pulley, I have toyed with the idea of a second alternator in its place, but I don't run a separate house bank anymore and rarely need more charging amperage than what my one alternator can provide.
That could change though.  I certainly have room for a lot more battery capacity amd if that were well depleted, it could chew up a single alternator if I were to ask it to work hard seeking and holding higher voltages.
Mainesail has an article on converting one alternator from internal to external regulation.  i do not how it applies to other makes of alternators, but if one can employ an adjustable voltage regulator, and cares to adjust it manually, fully aware overcharging is possible with enought drive time, then they can almost always recharge the battery as fast as safely possible whenever driving from A to B, and this is not possible when some automatic voltage regulator decides 13.7v is fine and dandy.
Those interested in this topic should peruse some of the articles found in the link below:
https://marinehowto.com/category/alternators/
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