How can I modify alternator voltage

[mobile_bob]

the white paper i guess was back about this time in 2009
has it been that long?

fwiw,  there might be something useful in the reading
for what you have in mind.

might be time to go back and reread it myself and make corrects where needed?
if you guys see something glaring let me know, and i will correct it.

http://www.microcogen.info/index.php?topic=157.0
(it is a pdf file for download)

bob g

[Tom Reed]

I remember that white paper well, just not well enough to remember the starter battery requirement. Mike and I both hand crank our Listeroids so no starter battery available. I like the idea of using full string voltage.

[BruceM]

I agree with Bob that a micro-controller for regulation is overkill and unnecessarily complex.  A single op amp comparator would suffice, and I'd use an LM10 to get the scalable temperature stable voltage reference it has built in.  That and a suitable MOFET is about it.  This is known as a simple bang-bang control, not PWM, though the effect is similar.

Using a micro-controller will also work, of course, and there's not penalty for excessive capacity and flexibility as long as you are familiar with programming and learning to program the Arduino. There are optically isolated SSR's that will do the job and can be directly driven by the arduino output.

http://www.crydom.com/en/products/catalog/1_dc.pdf

The crydom units above seem to have about a 3KHz limit for PWM.  Make sure you stay well under the max.  

There are logic level MOSFETs that can do this job also.

Maybe Bob can give us an gross estimate of field coil current for a 36V output a 20 amp charge rate?

[veggie]

Hi Bruce,

As noted earlier I am using Arduino because it's cheap and I have a stack of them. Also the Mosfet/resistor board modules are only $3 on Ebay.
Sensing will be from the full 36 volts at the battery, then through a voltage divider to step down to 0-5 vdc Arduino input as shown in sketch earlier in this thread.

Bang-Bang...op amp comparitor....LM10....Suitable FET (How do I know what is suitable??)....  LOL, I don't have a clue how to pull together the needed components. And for sure would end up missing something or using the wrong resistor. Magic Smoke !!!!!
And it sounds like that would need a back board and some soldering. ?  
That's why I use Arduino and add-on modules. They are great for the "electronic illiterate" like me.
The Arduino gives me some programing flexibility for frequencies vs. voltages. Also allows the control of other things at the same time.
Not necessarily overkill when the total cost is $20 vs. $150 for a Sterling External Regulator. ($325 for a Balmar)

cheers,
Veggie

[thomasonw]

Guys, overkill or not,  I am hurt that not one remembered an Arduino Alternator Regulator has already been developed.   Over 3 years ago by yours truly.   
http://arduinoalternatorregulator.blogspot.com/

Gee,  spend a few summers living the life on their boat and folks just forget you.   (BTW, have 1,000hrs on the Arduino based fully automated DC generator as well).

With a BOM cost around $50 I have sent out over 100x blank PCBs - lately to a lot of LiFeP04 folks as they like the ability to properly regulator (not just back off) the alternator temperate.  This winter am doing an updated version - might even do short professional assembled run,  would hope the cost could be under $100 all said and done.

Oh, and to configure it for '32v'  battery,  all one needs to do is send the ASCII command via a USB cable to configure the 'voltage multiplier' to 2.667  - works like a dream.  (36v?, send 3.0)

[veggie]

 thomasonw,

Oh Yes...I certainly remembered your setup. I love it. As I recall, it was available as a PC board only.
My obstacle is that I have never soldered components to a PCB and certainly did not want to make that my first attempt at delicate soldering.
If that unit had been available as a fully assembled regulator I think I would have bought one from you back when you were getting the boards made. But then it would surely have cost more ?
It would no doubt work very well for what I have i mind.
BruceM is very correct in saying, for a basic regulator a microcontroller may be overkill. I am always amazed how Bruce can pull electronic components out of his head to make a solution to a problem. For me however, I have to gravitate to what I am already familiar with.

So far I have mounted the Arduino in a small enclosure and connected the appropriate pins on the board to external terminals on the enclosure.
I ordered the mini-MOSFET "shields" (as they are called in the Arduino world) and now await their arrival.

Cheers,
Veggie

[mobile_bob]

if i had to guess the field current and voltage at 36vdc and 20amps output, i would guess somewhere
in the 10vdc range at around 2.5-3.5 amps for the leece veggie has to work with, that being if the alternator is spinning
at around 5k rpm... lower rpm and the field requirement goes up, higher and it will go down.

sorry Thomas, i forgot  your project!  geesh this getting older and busier sure takes its toll.

there you go Veggie a ready made solution, and if you can't or don't feel up to soldering, i bet you can find
someone locally to do it for you for very low cost.

a little practice, the right iron and solder, and it isn't that bad.

bob g

[thomasonw]

if i had to guess the field current and voltage at 36vdc and 20amps output, i would guess somewhere
in the 10vdc range at around 2.5-3.5 amps for the leece veggie has to work with, that being if the alternator is spinning
at around 5k rpm... lower rpm and the field requirement goes up, higher and it will go down.

sorry Thomas, i forgot  your project!  geesh this getting older and busier sure takes its toll.

there you go Veggie a ready made solution, and if you can't or don't feel up to soldering, i bet you can find
someone locally to do it for you for very low cost.

a little practice, the right iron and solder, and it isn't that bad.

bob g

Its Ok - I am somewhat thin skinned, but tend to get over it quickly.

Hey, just to restate it:  I have a few people who are interested in fully assembled (less plastic case) version of this.  This winter I will be looking into making up 10-20x of them - will have  a better idea once I hand solder the PCB I just received yesterday and proof the latest revs.   But if folks are indeed interested, would be a good time to get a fully assembled copy.

-al-

[mobile_bob]

just found this one this morning, 

http://www.ebay.com/itm/ADJUSTABLE-EXTERNAL-HD-VOLTAGE-REGULATOR-W-REMOTE-MOUNT-POTENTIOMETER-14V-20Volt-/301524938642?hash=item4634496f92:g:q8QAAOSweW5U2uNT

the seller has a couple other interesting offerings too, but i think the remote pot to adjust voltage might be useful to some folks.  mounted on the main panel it would make upping the voltage for equalization handy.

this looks like it could be used in a system that was described earlier, wherein we sample at 12v within whatever string
and power the regulator with an isolated 12v source.

this not to walk on the purpose built unit that our member has been working on, his unit if setup for 36vdc would be really a nice solution to the issue that Veggie is working on.

bob g

[veggie]

Yep, that is the Mechman/Transpro External alternator available here...

http://www.mechman.com/accessories/external-adjustable-voltage-regulator/

I contacted them but a few weeks back and found that they do not make a 36 volt or48 volt model.

veggie

[mobile_bob]

i figured they did not offer a 36volt version as it would be not as popular as 12, 24 or even 48vdc
however i still like the 12v version to be used in conjunction with the sense scheme that i outlined earlier.

again, i am only going over this again as a academic study and not to step on other options such as the
one that Thomas has been working on.

i like this latest unit, because of the remote pot that can be used not only for its obvious intended used, but
i can see the possibility of integrating it via the leads to the pot to a microcontroller, i will try to explain...

remove the pot, and insert a resistor bridge that can be switched in or out in a number of connections via 2 or more
output/relays controlled by the microcontroller.

in this manner one could have soft start capability, ramp up, or some programmed output to account for other engine loads
so that the engine could be operated within tighter range of efficient operation.

something like my trigen system, where i have an st7.5, twin 555jho's and a sanden refer compressor driven by an s195 changfa, now obviously i cannot drive all at full output, but i can drive all at partial output, where the microcontroller system manages the load seen by the engine and thus keeping it running at hear full rated load continuously. having the interconnectability of the 555jho regulator into the microcontroller would be most useful.

i believe this latest offering (regulator on ebay) is an interesting option, allowing someone like me to integrate it easily into my system.

years ago, delco made what was called the 1100080 alternator, large frame truck alternator that was very popular in the 70's and into the 80's, it had a rubber resistor block and a small red cap you could position in one of 4 ways which set the output voltage.  that regulator if one were to remove the resistor block and insert the resistor bank and microcontroller could also be used  for the system.   those regulators are to find today, there lots of "will fits" but hard to find the right one today.

now the old delco regulator would work, but i think this ebay unit with external pot is a bit smarter internally than the old delco regulator, for whatever that might be worth?

btw, i got the other regulator we talked about recently in from ebay, and will see if it will fit and if it works as expected for this use using 12 volt excitation and higher voltages, via the sense scheme.

more later
bob g

[mr.fixit]

Does that ebay regulator have a separate voltage sense line?

This is the the one I am using, http://www.ebay.com/itm/Marine-Advanced-Alternator-regulator-with-upgraded-software-/200923664443?hash=item2ec7fbd03b:g:WVAAAOxyVLNS5mAc&vxp=mtr
Works as intended charging 48v battery bank, but voltage setpoints are limited the a few options via dipswitches.
Sometimes it loads the alternator right away and sometimes it delays like it's suppose to, not sure what the problem is.

The fleet I worked for had several trucks with that delco alt. with the red voltage adjust plug, brings back memories of younger days!

[mobile_bob]

+1 for younger days! 

nobody told me i would be an old fart in a blink of the eye!

those delco's were just about as prevalent as
8v71 detroits, 290/335 cummins (ntc series)
1693 cats,
rto-9513 fuller transmission
sqhd rockwell rear axles

can cabover trucks were about the only thing on the road, at least for interstate use

yup things were so much simpler then.

although there were some crap that we had to deal with that actually improved over the years.

when was the last time you replaced a speedometer/tachometer cable?

or a right front wheel gear driven speedo hub mounted gear, with the concentric driven gear?

or leather wheel seals and grease packed brgs.  or worse

do you remember the 220 cummins with that dreadful rollup sock oil filter that was fitted into the oil pan?
or the big mess relating to over fender mounted luberfiner filters!  i sure was glad to see those go away.

sorry, i digress

bob g

[thomasonw]

Yep, that is the Mechman/Transpro External alternator available here...

http://www.mechman.com/accessories/external-adjustable-voltage-regulator/

I contacted them but a few weeks back and found that they do not make a 36 volt or48 volt model.

veggie

FWIW, the Transpo 911 regulator is the 'truck' regulator I have used for years after tossing out the fancy Blue Marine Unit, and before my project.  I still carry it for a backup.  Has been a reliable unit, but I do not remember then being so costly.  IIRC, I paid around $50 for it....