Micro CoGen.

Hi All,

I need a bit of help with a solution to change the voltage of an alternator.
This solution has to be as inexpensive as possible so adding a Balmar Regulation system for $300 is not feasible.

Here's the conditions:

Engine --> Alternator --> 36 volt battery --> 34 - 36vdc inverter

PROBLEM:
My two alternators are 12 volt or 24 volt.
I would like the output to be a regulated voltage in the range of 34 to 36 volt.
The battery is just a voltage clamp and I am not interested in charge algorithms. Power will pass through/around the batteries to the inverter.
Is there a simple and inexpensive way to modify the output voltage of an alternator?

Both available alternators are the Leese style with easily removable/accessible regulators mounted on the rear of the body.

Any ideas ?

Thanks,
Veggie

The 24V alternator might work reasonably well at 36V.  You will need to modify the regulator or replace it.  If you can find a schematic for your existing 24V regulator, I'd be glad to take a look regarding modification.  If it's all potted, that won't fly, of course.  A homebrew circuit for this would consist of a voltage reference and op amp comparator driving a low side MOSFET.  No PCB needed but some experience in electronics is needed.  Parts cost should be under $35 at Digkey.

i don't know what alternator you are using, which would help

there are several ways to do this, it all depends on what you have to work with.

bob g

ps.  do you have a possible source for field current?  if you are using the 12nominal alternator
then you need a 12vdc source that is not tapped off the battery bank, but better a source from the inverter
such as one of those cute little pwm power supplies that are all over ebay and elsewhere.  if using a 24v nominal alternator
then you need a 24vdc power supply, and

we need to know what rectifier your alternator is using?  are they avalanche diodes? if so you may be limited to using the 24volt alternator as the 12volt with avalanche typically start to clamp down at around 30vdc output.

depending on what you have, the diodes can be replaced with some 200piv 50amp press in replacement non avalanche diodes, then you can make the alternator put out anything you want up to 100plus volts without much trouble, albeit a bit dangerous at that high a level... but for up to 48vdc nominal (56vdc charging) no problem.

if you are faced with changing diodes, i would start with the 12 volt alternator, as the stator is likely half the resistance
with less turns having less inductance, both of which really have affect on efficiency.  the units i worked with had no problem getting up to around 80% efficiency using 12volt field and 12volt stators, running at 28.8vdc (24v nominal) at 100amps output, running stable and cool doing so.

fwiw,  i also used the same units, with 200piv diodes running at 56.6vdc (48v nominal charging) at 60amps running a bit warmer but well under limits, at better than 70% efficiency ( i don't recall exactly, but better than 70 and under 80)

the bottom line is you can get a 12 volt or frankly any alternator to produce any output voltage you like, and there are a variety of ways of getting there...

i like Bruce's comment about a purpose built regulator as well, that would be interesting too.

also the balmar is expensive, however there are other alternatives such as those built by "sterling"  that sell for around 100 bucks new, that could be adapted to your needs.

Bob, Bruce,

I will gather some information about my specific alternator models and get back soon.

In the meantime:

Yes: even though I will be making 36 volts I do have 12 volts available from the starting battery if needed for field control.

ALSO: I have a few of these variable voltage regulators if that would be of any help in controlling field voltage.
Let me know if this can be of any use. It can take 12 volts ( or 36 volts) and reduce to whatever I need.
< click picture to enlarge >

That is a linear regulator- not useful for controlling the field current of the alternator to regulate the ouput voltage of the alternator.

The alternators that I have available are:

A] Leese-Neville BLD-2331-GH   (12 Volt)

B] Delco 26SI   (24 volt)

I am unable to find a wiring diagram for either unit, however they both have regulator modules screwed to the back.
The Leese regulator is a separate external module screwed onto the alternator body.
The two pictures below are the 26SI Delco.

The PDF which shows an exploded view of the unit refers to the Leese.

i generally prefer the leece neville for this purpose

http://www.prestolite.com/pgs_products/specs.php?item_detail_id=29858&item=BLD2331GH

it appears to be an updated and heavier duty 555jho, which was 160amps and yours is 185amps

i have no idea about the diodes, they appear to be press in and therefor  could be replaced with the 200piv units
i mentioned earlier.

the delco you have having the externally accessible regulator makes it also something that could be used for your purposes.

if it were me, i would got with the leece, given its record for use such as you have in mind.

bob g

Bob's your uncle on this- my only experience with alternators is my DIY linear regulator for a MB300d alternator and my DIY ST regulator (a bang-bang type low side DC switching regulator). If electronics isn't your thing, you are stuck with whatever you can find for a 36V regulator.

The basics are pretty simple: the field coil current is switched on/off to keep output rectified 3 phase DC voltage withing specified range.  The output 36VDC (nominal) could be used for excitation of the field coil, if you keep duty cycle limited so the field coil doesn't burn out.

Hmmm...
Ok, before I go any further down this path of hand building a custom regulator, does anyone know of a better way to get a regulated 36 volts DC to supply into my Grid Tied inverter ?
Prime mover is a 4HP diesel.
My power requirements are 36 volts and 30 amps ( or 1080 watts )

Veggie

for crude, you can use the centertap off a power rheostat and get your drive current from that, but it would always be wandering around.  Have to find the current/amps value of the winding, and have the rheostat consume about 2x that to keep the current stable.

or google " adjustable automotive voltage regulator " and there are all sorts of ideas.

Could be as simple as isolating the existing regulator with a 24V zener.  May need some caps and swamping resistors to keep it stable

Quote from: mike90045 on September 24, 2016, 10:27:01 PM
for crude, you can use the centertap off a power rheostat and get your drive current from that, but it would always be wandering around.

Mike,

Hypothetically, with a center-tapped rheostat would the alternator output voltage always be wandering if the alternator RPM was kept constant and the load on the inverter was also constant?

Veggie

there are various things that will cause it to wander, heating is one of them
as the alternator warms up the voltage will change,  myself i would never support any scheme that
required babysitting other than the most basic machine used in an emergency installation using minimal parts
in a shtf scenario babysitting the regulator to keep somewhat stable control is probably the only place that i could
see as being viable.

one last question

are you concerned with efficiency?

if efficiency is of paramount importance, or very close to the top consider this

the leece likely has a lower stator resistance than delco, every 24volt automotive alternator has a higher stator resistance
than ones used with 12volt systems.

stator resistance plays a very significant role in efficiency when it comes to getting higher voltage output,

also 24volt stators have more turns per pole on the stator, in order to get a low rpm cut in for charging.
more turns increase the inductance of the stator,

higher inductance, makes for higher reactance the result being another signficant decrease in efficiency.

in my testing i reconnected 12volt stators from delta to wye in order to get more voltage, this increased the effective
turn count per pole, and the inductance/reactance,  the result was a much hotter running stator and dramatically lower
efficiency (down from around 80% to around 55%).  the only benefit was lower cut in for charging at the higher voltage.

so i opted for higher rpm, delta connected 12volt 555jho type alternators, made for 12volt operation, and yes i had to turn
the rpm up to ~4800rpm to get 100-130amps at 28.8vdc and was still able to get ~50-60amps at 57.6vdc.

yes higher rpm results in higher losses due to windage and friction, along with higher frequency increasing reactance, so there are also losses associated, but apparently less so than going the former route.   apparently higher turn count and higher resistance are the prevailing killer of efficiency for these machines.

also of note the 555jho and its variant (which i believe your leece to be) have a higher pole count than the delco units, this enables a lower rpm to get the higher voltage from.  the 555jho also has a short stator relative to most all of the more common leece neville offering such as those of the JB family.  the JB family has a very deep or long stator, resulting in a lot more wire and then more resistance.. this is the only reason i have not embraced the JB family of leece neville alternators for this intended use.

having said all this

i would recommend using your leece, i would remove the regulator and gain access to the brush holder, which is right under the regulator, there will be two male spade terminals to direct connect to the rotor/field.

if you have a 12volt source of dc power, such as your starting battery, you are well on your way.

the only thing you need then (if you are buffering with batteries for 36volts?  i assume so)  take a sample line off the first 12 volt battery in the 36volt string.  this is your sense line.

look for a sterling regulator, they are about the most reasonable regulator on the market, there used to be a couple vendors on ebay selling them.... you want a 12volt unit.

you derive the power for the regulator from the starting battery,  you sense the 36volt string at the first 12volt, connect the regulator sense to that battery positive post, connect the regulator to the field of the alternator, then spin the alternator up to about 5000rpm and you will be charging at 36vdc nominal, and have the ability to program the regulator for soft start, whatever battery technology you want, whatever voltage setpoint you want, and also depending on regulator model have a temp sensor to monitor the battery temperature and the alternator stator temperature so that both are protected.

if you are feeding a grid tie,  i would still use a battery bank to buffer, and the battery bank need not be some large deep cycle set, 3 matched small batteries used for small cars would be more than good enough to get the job done.

done this way the alternator will run just fine for a very long time, provided (which i almost forgot) that you change out the press in diodes for 200piv non avalanche style diodes,  don't fret the changeover, any alternator/starter repair shop can change them out, and likely already can provide an aftermarket rectifier bridge to replace yours with... you just need to tell them that the alternator will not be used in a truck and not be used for 12volts anymore, tell them it will be doing 36volt duty and they will understand...  the diodes cost about $7,50 each in 2011 dollars US. (retail),  you only need 3pos diodes and 3 negative, for a total of 6 diodes to do the job.

i hope this helps
bob g

apparently this is the latest offering from sterling, it uses a sense wire so it will work for the intended purpose.

http://www.ebay.com/itm/Sterling-ProReg-BW-Advanced-Alternator-Regulator-100-Amp-/171771756153?hash=item27fe64fe79:g:K74AAOSwzrxUyWLR&vxp=mtr

here is the installation manual, with more details about the unit.
https://cdn.shopify.com/s/files/1/0658/7343/files/eng_fre_ger_a5.pdf?483

this unit is more expensive than what their earlier offering were, maybe they are better, maybe they are just better packaged
i don't know.

i will look further for other options
bob g

here is another possible solution, and it will bolt right onto your leece alternator in place of your oem regulator

http://www.ebay.com/itm/Voltage-Regulator-Motorola-Marine-Mercruiser-Alternator-/231997059754?hash=item36041a32aa:m:m_p3XU3nyRnqvmgYJpsrheQ&vxp=mtr

now it doesn't have a sensor for battery temperature, it does have adjustable voltage that is useful
and it has the remote sense wire, which is mandatory for what i have outlined so far.

the price is certainly attractive! at $39.99 with free shipping?  hard to beat that and in my opinion
something that is worth a shot with this sort of project/prototype.

actually this is the regulator i looked for high and low 10 years ago to use in testing,  and i am convinced
that even though it isn't programmable, and doesn't have all the other bells and whistles, it does have the basic
requisites to use in this application.   even if it didn't fit the back of the alternator you have, it could surely be remote mounted to a panel and wired from there?  i think i am going to order one, and maybe work with it this winter in testing.

the only wire used off this regulator that would be connected to the alternator would be the two field wires, the red and black with eyelet connectors would be connected to a 12volt source that is isolated from this unit, and its 36volt battery bank such as the starting battery.

so connect the black and red with eyelets to the 12volt starter battery,
connect the sense wire to the first battery in the 36volt string
connect the field wires to the brush holder,
mount the regulator to the rear of your alternator

start her up, raise the rpm up to where you get charging, at 36vdc nominal, and adjust the regulator voltage to whatever you like, such as 43.3vdc? or so. and you should be golden
most of these regulators taper back the output as the alternator gets hot, so there is some overheat protection.

remember that by adjusting the regulator you are adjusting what the regulator see's at the sense wire, and because the field is 12v nominal and is powered by a 12v regulator which is fed by a 12v isolated source,  the system really doesn't know about what is happening at the output side of the alternator, but has control over that because the battery being charged (36vdc nom) is made up of 3 batteries the first of which is being monitored....

if over time there is an imbalance between batteries, which really should not be a problem, all you need to do is move the weak sister into the number one battery position and let the system sense from that battery and it will them be pulled up to where it needs to be to equalize.

bob g

before you buy the 40 buck unit, let me look into it further

it has the needed sense wire, which i had wrong, it is the "red" wire with an eyelet connector

apparently the ignition wire "purple" is the wire that powers the regulator,  which seems right to me

i think i will order one, to check fit and how it works,  and will let you know as soon as i get it and have a bit of time to do some testing.

looking further it looks like walmart even sells it for 35 bucks! hmmm
https://www.walmart.com/ip/NEW-REGULATOR-FITS-MERCRUISER-INBOARD-ENGINE-198-228-255-330-340-5-7L-7-4L-898-5-240/165067336

i am not sure if the unit will bolt on in place of the oem regulator,
the unit i am looking at here will fit the motorola unit,  the motorola 8mr series was the grand daddy of the 110-555jho and your alternator marketed by prestolite and now leece neville..  these units are very very close sharing the dna of the motorola however the regulator might, and i mean might have a slightly different bolt/screw pattern.  however this does not preclude its use as a panel mount regulator for the proposed purpose.  you would simply remove your oem regulator, disconnect its wires internal and external and tape them off, connect new field wires to bring out through the grommet and reattach the oem regulator as a dust cover... or remove it and go get a blown oem regulator and dig out the potting compound and remove its innards and clean up the housing to use as a dust cover... i have done this a lot.

by the way,  it appears like alibaba has chinese suppliers of this regulator for between 1.5 and 3.5 bucks in quantities of 200 units.    i guess if the time comes we get enough bodies back on the forum needing to develop engine driven high efficiency chargers for 24, 36, 48 or whatever... maybe we could do a group buy, or maybe there is a chinese company that would sell in quantities of less then 200 units...  crap at 1.5 bucks and 200 units it would still be less than a balmar even if not as advanced and not having all the bells and whistles.

the bells and whistles to a large extent could be added with a micro controller and a i/o relay board, maybe a couple temp sensors or even temp switches like the temp snap switches... we really only need over temp cut out or limit switches for two states, ok run and oh hot don't run.  i think there is much that might be done in this area that would be quite useful
and would not be tied to just one type of alternator,  this system would work with many other types so long as you can get access to the field connections internally and the rectifier bridge can handle the higher voltages or be able to swap out the diodes as previously stated for higher output.

fwiw


thanks
bob g

Thanks for all that useful info Bob.
I will continue to research this stuff as well.
Let me (us) know as you learn more about that $39 unit. Looks like a great low priced solution.

Veggie

Very impressive, BobG!  Feeding the alternator + output to 3 - 12v batteries in series and using the lower voltage battery as feedback for the standard 12v regulator is a brilliantly simple solution.  Only finding a 12v regulator with a separate battery voltage sense, not hardwired to the positive output remains to be solved.  Wow! 

Bruce

this was the basis of the white paper i published here back in '09 or so

at that time the only isolated sense regulator i could find was one of the balmar units or rebadged units sold by xantrex

at that time i found various units that were similar in operation to the balmar, most all of which i bought and tried out, all of which worked just fine for using the 12v nominal alternator for 24 and 48 vdc operation as described in this topic and the white paper.

it is my belief that this scheme could be used for any voltage (DC) that one might want up to maybe 120vdc or so, the limit becomes what the bridge rectifier will handle (PIV rating) and the insulation quality of the stator, along with obvious safety issues relating to exposed studs for the output current.   the only reason i could see going to anything over 48vdc nom would be the use of surplus ups inverters which sometimes come in all sorts of higher dc front end voltages, i have seen 60, 72, 96 and higher voltages... again that might be something to work with if one had a source of surplus ups inverters in higher dc voltage battery banks?

while i am not particularly scared of 440 3 phase i am however really scared of 240vdc battery banks, of which i had one 15kva inverter from an exide ups system.... that sort of battery bank (240vdc) has a horrendous amount of instantaneous power as evidenced by a hole that looked like a "ma duece" had her way with the steel cabinet!  i made up my mind that working with that inverter was something i really had no real need for.

of course i digress , something i am getting better at in my older age. :)

anyway, alternators such as the ones Veggie has have some really excellently insulated stators, so i think a new stator could certainly handle some pretty high voltages without burnout in that regard.

lastly the other requisite that the leece alternator that Veggie has to choose from has an isolated ground post, so that the output of the rectifier bridge is fully isolated from the case ground... this is something that is a must for what is proposed.

having the battery bank isolated from the grounding of the engine/alternator and the regulator save for where it must be connected saves those pesky unforeseen back feeding on the ground side that cost me one 400 dollar balmar.

i tried to sample from the #2 battery in a string of 4 batteries, which of course required tapping a ground off the #2 to get the needed 12volt sense, but also provided a 24volt path that proved to let the magic smoke out of the regulator because of another ground path. 

so i am a big proponent of a good schematic, and only sensing off of the #1 battery and making darn sure there is no way there is any backfeeding of anything other than 12v nominal getting back to the regulator.

the use of a 40 dollar regulator sure takes the stress out in prototyping, loosing a 40 dollar regulator due to a mistake sure is no where near as painful as 400 dollars!   i still can't bring myself to throw out that regulator!   

bob g

I also remember one of the marvelous research papers on  claw pole alternator designs which you posted, BobG.  Very interesting and educational.  Claw pole is a lot more efficient than I realized, and is underutilized outside of automotive alternators.

I agree on the sometimes very expensive lessons for DIY R&D.  I've had some expensive education myself. Like my brilliant 1500 watt switched capacitor variable output linear 120VDC battery bank charger. It had such bad PF as capacitors were dynamically switched in before the filter choke boosting voltage and current that it made my custom ST-3 AVR regulate so low that the 240AC power relays chattered and fried.  After redesigning the AVR to do RMS voltage regulation I then found that while the charger worked, my shop heat lamps were then unbearable re: flicker.  In disgust I then abandoned the brilliant capacitor switching design the custom PCBs to the trophy shelf and motorized a old variac instead.  The technically primative Variac design, of course, has worked flawlessly since it's first test run and the 9 years of service since.  I've tried to avoid brilliant designs since. ;)

As it turns out, my 36 volt battery does consist of 3 small AGM units, so sensing from battery #1 (12 volts) as Bob suggests is not a problem.
While Bob looks further into the $40 regulator, I have a question regarding regulation of the field power.

REGULATOR IDEA:
A small Arduino microprocessor board has several pins capable of outputting a pulse width modulated signal in 5 vdc and the PWM frequency can be software controlled.
Other pins on the board can read the voltage of the 36 volt battery bank (by means of a voltage divider converting 36 volts to the board's 0-5vdc input)
Does this make for a simple and inexpensive regulator platform?

Begin loop
-Read Battery Voltage (Input pin)
-Compare to desired target voltage
-Increase/decrease field winding PMW signal accordingly (PWM output pin)
Loop

Granted there may be some other electronic components needed. But the overall package would be fairly inexpensive (since I already have this stuff).
One thing I don't know how to do is take the 5vdv PWM signal from the Arduino and step it up to the voltage necessary for the Field Coil (12vdc???) while still retaining the pulsed output.
Another thing needed would be a simple algorithm to determine how much to change the PWM frequency each time a change is needed. The simplest way would be a series of if/then statements based on the offset between the desired and target battery voltages.
If one wants to get fancy, a fuzzy logic or PID routine could make the decision.

Any thoughts on this ?

Veggie

 ... AND !
After digging around on the web I came across this fellow who seems to be doing just that.
An Arduino configured as a voltage regulator.
Perhaps this might work.?

https://www.youtube.com/watch?v=zfGm0gZhgCc (https://www.youtube.com/watch?v=zfGm0gZhgCc)

I defer to our resident electronics expert "BruceM" for input ?
Can the 20mA,  5v PWM signal from the Arduino be stepped up in amperage to satisfy the requirements of a field coil (Perhaps up to 4 amps)
Maybe a transistor or a FET in the circuit?

And MobileBob ! do you know the voltage range that the 12 volt Leese Field Coils typically require?
Although the battery voltage is 12, I wounder if the typical field voltage provided by the regulator is much less (like 0 to 6 or something)?

Veggie

BruceM,

How fast can a Solid State Relay (SSR) change state ?
Can it handle the frequency ?   Hmmmm....
The output of the SSR to the field could also be 12 volt instead of 36v if needed by using just one of the three batteries for power.
The big question is whether the SSR can switch fast enough.

The two heavy connections on the alternator sketch are it's output. The two spade connectors represent the field.
See picture.

Veggie

Maybe an SSR can in fact switch fast enough to control the field winding.
I found these as examples of high frequency SSR switching....

MOTOR
https://www.youtube.com/watch?v=LL2Sryi57xA (https://www.youtube.com/watch?v=LL2Sryi57xA)

MOTOR
https://www.youtube.com/watch?v=NQ08OztPkb8 (https://www.youtube.com/watch?v=NQ08OztPkb8)

SPARK PLUG
//https://www.youtube.com/watch?v=AZWdRX2MGNg

i think a mosfet could be used as the link between the arduino and the field coil

iirc the leece neville under the following parameters used 10vdc at around 3.5amps

that was for 100amps output, at 28,8vdc running at 4800rpm

of course the voltage and current will change if any of the parameters change, the voltage and current are tied together
to a large extent and both go down as the rpm rises, or go up as the rpm is lowered. and of each will change as the demand for output current is reduced.

because i could not easily change or increase the rpm on the trigen as the belt drive was fixed and the rpm set on the engine at 1800rpm the voltage and current were significantly higher running at 57.6vdc at 50-60amps for 48vdc charging... i don't recall exactly, but if memory serves me the voltage was around 12volts and closer to 5amps to the field.

bob g

fwiw

the delco alternators from pre computer days used pwm scheme to control the field current and ran at around 400hz
so switching speed is not high by most standards, at least electronically, too fast for a relay, but certainly something any power transistor can handle.

as a matter of fact the delco regulator from the late 60's and up into the 80's used on the alternator style like your delco used as a regulator a circuit board with one power transistor (DO-3?) and a couple of small transistor, some resistors and a pot to adjust the output.  those schematics are widely available and might be a good place to start for making a 36v regulator. 

the use of a microcontroller, in my opinion, unless you are planning on other functions seems to be overkill for what is needed.  but heck roll with what you feel comfortable with.

bob g

Thanks very much Bob, that gives me a starting place for field voltage levels.

Reasons for using the Arduino are....
1- Dirt cheap $18
2- Programming allows me to alter frequencies and charge mapping in minutes
3- Stuff like this is available....Mosfets with the accompanying resistors
http://www.ebay.ca/itm/3V-5V-Low-Control-High-Voltage-12V-24V-36V-E-switch-Mosfet-Module-For-Arduino-D-/112073228788?hash=item1a1815c1f4:g:zfcAAOSwqfNXmM-M (http://www.ebay.ca/itm/3V-5V-Low-Control-High-Voltage-12V-24V-36V-E-switch-Mosfet-Module-For-Arduino-D-/112073228788?hash=item1a1815c1f4:g:zfcAAOSwqfNXmM-M)
A mosfet board that connects directly to the Arduino may work very well.

Oh...yes...and the biggest reason of all, I know very little about sizing electronic components and building circuits myself so using "building blocks" like Arduino and Arduino "add-on's" makes projects go a little smoother. I am also a programmer, so making the Arduino do various things is not that hard for me.

Onward,
Veggie

Beware of the field sucking power from 1 battery, that it gets undercharged.

Good point Mike or over charging the other 2. I was up your way last night fighting the Oil Hill fire.

that is why you don't provide power to the regulator from the string, but rather from the starting battery
the regulator only takes off the sting at the 12volt level as a sense, and doesn't take but something on the order of a few
milliamps.

if we were to take the regulator power and by extension the field power from that first battery in the string, then yes in a very short while there will be an imbalance in the string, and that is about the last thing you want happening.

an imbalance in the sting is very hard to get back right again.

the white paper goes into detail on this if i recall correctly.

the bottom line is this, never under any but dire emergencies should anyone tap into a series string of batteries and take off power.  tapping for a sense line is another thing all together and not really a problem.

all series strings over time will have some imbalance issues, that is one of the purposes of equalization.  also not that the number one battery in the string could be swapped out for a weaker sister so that the sense line is attached to that one and aid in getting the weaker one back or nearly back to normal levels of charge.

bob g

more thunkin

if you are going to build a purpose built regulator, there is no reason why you could not take the power from the full string
at 36v nominal and via pwm reduce the effective field voltage down from 36 or whatever to sub 12vdc needed by a 12volt field.  then you could sense the voltage of the total string and avoid all the other stuff.

not really any different than an st head with an electronic regulator, where the output is 120/240 and the field is something much less, like 60vdc.

the field can be anything and limited by what you can get off the shelf in parts,  the output can be anything other provided you have enough rpm and diodes able to handle the higher voltage.

some years ago, i rewound a leece neville JB series for 60 hz output at 600rpm,  it was capable of making 120volts dc at 6amps due to the small wire used to rewind the stator.  the field required 12vdc at 5 amps to do that job.
interestingly at around 2400rpm it would put out 480ac at 240hz with the same 12vdc at 5amps field current. 

and no i never used it for anything other than an exercise in what is possible.  and yes i think i still have it somewhere packed away and if i find it will destroy the thing for fear it might show up in my auction after i am gone.  i sure would not want anyone playing with that thing because it can and will kill quite easily.

point being there is much that can be done with off the shelf parts and a little ingenuity. moreso if you have some background it electronics/microcontrollers and such.

bob g

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

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.

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?

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. ?   :o
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

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/ (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)

 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

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

Quote from: mobile_bob on September 30, 2016, 10:16:21 AM
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-

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

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

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

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

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!

+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

Quote from: veggie on October 05, 2016, 03:15:37 PM

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

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