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12v system and the pulse width modulated power supply

1918 Views 16 Replies 7 Participants Last post by  voltreg
where to start
hang on to your hats this is going to get crazy
maybe its all the evil thats going on in the world that prompting me to post this
Putin or the people that control him comes to mind
or the feeling that AI is zeroing in on me is the other reason
maybe instead of trying to rule the world i would rather fix it
thought i would be safe posting on an off the beaten path forum, but i see that quickly changing
i type with two thumbs is the main reason my posting are short
i suck at spelling, so for the speed of wrighting this i will have mistakes i wont spell check but i think you will get the jist
so there is the short version and the long version your going to get the long version only becouse there is a lot of humour in this and you will maybe understand me a little more and where i come from
thats the opening post and im going to start at the age of 4
feel free to add insight and hope you injoy my posts
i will try to post every other day untill this is done
until the next post
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Err, should this be in the Totally Off Topic forum supchrgamx? I mean sure, you are covering a lot of ground in your post above about Volt engineering, but... :)

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16,17 volt
1,242 Posts
Discussion Starter · #3 ·
Err, should this be in the Totally Off Topic forum supchrgamx? I mean sure, you are covering a lot of ground in your post above about Volt engineering, but... :)
AI and me are getting crazy, and i will touch on this down the road
heres the thing, gm is looking for someone on the 12v system and when it was presented to me on my news feed i check into it, not that im looking, you could work from home for the most part, pay is the same as im getting now with my qualifications, but i pay no union dues and sleep at my desk. so no advantage to jump ship
but i can still help
so if you want to move it, im ok with that

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16,17 volt
1,242 Posts
Discussion Starter · #4 · (Edited)
so age 4
started with me taking my moms wind up wrist watch apart to see what made it tick or more importantly, what powered it
thought at first that it was the balance wheel return spring that was doing it but quickly realized it was some thing else
dad had a jeweller set of screw drivers that i used to completely strip that watch down to the primary spring
once i saw and played with that spring, i totally understood how a watch worked
mom saw the watch totally striped down to all the gears and stuff, i remember her saying, put that back together
i was 4, so that didnt happen , didnt matter to me, i just wanted to understand how a watch worked
4 to 14 i was a kid, my bicycle went from a single speed to a 3 speed, 5 speed , 10 speed, 15 speed, taught myself how to paint on its frame, bike ended with a radio, lights, signal lites, mustang bike with sissybar and apehanger handle bars and a cb radio , respoking the wheels and all the work was done by me, honing my skills
so now its grade nine (14) that i got into electronics, library had popular electronics that i took out and it had a 2 transistor siren that went up and down in pitch. when i went to the store to buy the parts the fellow on the other side of the counter couldnt stop laughing, becouse i didnt even clear the counter. took my parts home, had no soldering iron so i used a piece of plastic and drilled holes in it and used screws to join all the components, surprise to me, it worked. so what do you do with that, take it to school
morning class, english, half way through the class, hit the siren, every one was looking around as well as me, 3 second blast, waited a while and did it again, this time everyone was honing in on me. at that point the teacher got up and started walking up and down the isles and stopped at me. the speaker had fallen out of my pocket and was hanging by the wires, made me give it to her, the 6 million dollar bionic man was popular on tv at that time, so some smartass at the back of the class says, he couldnt afford the 6 million , hes the 2 dollar man, for the rest of grade 9, i was known as the 2 dollar man, i didnt think this through, the upside to this, the dramma teacher heard about this and got me to build a podium with flashing lites for their time machine. for a competition between 15 schools that i became a part of,
we won first place.
grade 10 we moved to a new city, so a fresh start

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16,17 volt
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Discussion Starter · #5 · (Edited)
grade 10 had 2 hrs every morning in electronic , grade 12 i worked at a tv and stereo repair shop evening and weekends repairing stuff. so me as a kid had access to variable analog power supply, scope, electronic components and becouse we also fixed mechanical pin ball machines , had access to flipper solenoids.
computers were there, but not mainstream yet
evening, if there was no customers, i would screw around with stuff
most house stereo even though you plugged into 120v ac, were run on 12v dc at the time and i used them to mess around
i would reduce the voltage till it either produced distorted sound or some would just cut out, i used the second type that cut out at around 9v.
i would use the power supply to get everything working and have capacitors to store the voltage, its like a short term battery. disconnect the power supply and then hit it with a solenoid and see what happens
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first pic is just on capacitors , second pic is more capacitors that didnt change the time it spent at 0 volts much.
but when you left the power supply connected the 0v time change to a split second when you connected the solinoid to it, thats important. all those conditions stopped the sound from the stereo until the voltage recovered.
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these pics are when i increased the voltage of the power supply keeping it connected and then hit it with the solenoid
that prevent the voltage from hitting 0v and at 15v the stereo kept working through the solenoid apply
later i tryed it on 5v regulated circuits with the same results
initial current inrush of a solenoid is cool
so you can see that at 15v the solenoid has no effect on a 5 volt computer circuit. number 1 reason that tesla went to 15v. i think there are some smart engineers over there
the power supply i used was analog, or it provided a smooth power output
enter the pulse width modulated (pwm) power supply, it does not provide a smooth power output
but it will handle a high power output with lower heat and with low component count. it has its place

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16,17 volt
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Discussion Starter · #6 · (Edited)
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pwm power supply works at a freq of im guessing for gm at 28000 cycles per second or 28 khz
it varies the output by varying the duty cycle at the same freq. so 30% of the time is on and 70% of the time is off, for low output and will sweep through to 70% of the time that is on and 30% of the time is off, for full output, doing all this at 28khz per second
even though it does it fast, lets look at it over a second, if the cars battery is fully charged the pwm power supply will have low output, so 3/4 of a second it is off and 1/4 second its on. if the battery is depleted, the opposite is true where the pwm power supply is 3/4 on and 1/4 off.
far as the power supply is concerned it has better protection when the battery is depleted
that statement in it self is wrong. better protection when the battery is depleted
now lets look at the battery
ever put a battery charger on a lead acid battery if you did the charging is not consistent you will see the amp gauge bouncing around as the gases in the battery get in the way of charging. so there is no reason to believe its any different when discharging. tesla changed their 12 v battery to a lithium battery, to do away with this
the down side to that, is once you kill a lithium battery, chances are, it will not recover, as a lead acid battery will.
so what does all this mean

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16,17 volt
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Discussion Starter · #7 ·
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ok we are almost there
so the top pic is the pwm power supply pulsing 28000 times a second into the 12 battery, those combined will be a smooth 12v out.
the way it should work
the bottom picture is the same but with a weak 12v battery that a solenoid pulses between the pulses of the pwm power supply
so the pwm power supply is no help, because it is off at that moment, so your circuit is relying on the 12v battery.
so if your battery cant handle the inrush current of your inductor when it turns on, your circuit can hang at 0 volts until the magnetic field builds in your inductor to reduce the current and have the voltage recover
thats a mouth full
standard electronic stuff
I started clueing into it after my becm died on my 2017 volt, and not becouse it died, but shortly after it, i started to get all these error codes coming up in the car. once that happened i knew that it was the power supply causing this, becouse that what power supplys will do. I been fixing stuff way to long:)
i know what you are wondering, how can something that is happening that fast, have any effect on any thing.
a light bulb doesnt care
most of the circuit in the car wont care due to the capacitance of the circuit, that allows it to get past those dead short pulses
its the circuits that follow that voltage that fast, that is the problem, little to none capacitance in them
so some of the circuits work and some of them cant and there is nothing harder on electronics than this
becouse now when something is suppose to turn on or off, it cant becouse what controlling it doesnt have the voltage to do it. when the circuit recovers the computers have already sent the command to back something off when the circuit was screwed up, so it was not received and then stuff keeps working when it should be shut off and thing then blows up
do you feel like your back in school:)
when i realized what was going on, i tryed to get a new battery from gm, they had to order it
so at the same time i ordered a 1 farade capacitor to fix all of this, becouse i knew how hard it was on my electronics and i knew that the new battery would get old and try frying something else later on
Automotive tire Reflex camera Electronic instrument Gadget Trunk

so you can see my belva capacitor sitting beside my 12v battery (all in i think it was 56.00 bucks)
got that before my new 12v battery and installed it. all my computers settle down even with the old battery
been over a year and no computer issues
for me its reasonable to believe that the power supply also fried my becm
for the simple reason it followed the same time frame as my battery going bad after a few years
it why i think it has something to do with the bolt batteries as well, same time frame
cant say for sure but i have my suspicions

great, a whole bunch of useless information
how do we fix it

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16,17 volt
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Discussion Starter · #8 ·
before we get into my solutions, i want to make a few comments on how i arrived at this point, on this forum. its really been an i opener for me. i have never engaged in a forum before and has not been a smooth thing for me.
in order for me to do my work; i have to have a really high level of sensitivity, that gives me an ability to interact with machines on a machine level. just to give you an idea of how high of sensitivity this was. when i first started posting, it was becouse this was new technology to me and i wanted to learn more, you were not people, but a medium to your cars. I'll give you some highlites of this. when someone posted derogatory comments to me, the letters on the screen would turn red. so i had this to deal with along with cant type, spell , you get the point and it hit a peak when i said something and when i opened this forum and read the response, i actually felt a push back from the internet to the point of me saying "wow" need to turn that sensitivity dial down a bit
i have read some of my post later and even said to myself what an ahole. it wasnt that i was a jerk, it was just that i was that bad at posting, even mr dave wanted to throw me in jail and it was someone high up in gm that talked to me on this forum and i all i said at the time was that i was just goofing around.
nor was it me being a know it all, as some of you thought, more along the lines of, in my journey of learning new stuff I could help other and tryed to interact to help and yes not always being correct
being incorrect is no big deal for me becouse when you fix stuff, incorrect is just part of it
so i just want to thank everyone that interacted with me, good or bad becouse i can now interact to the point of this post, knowing that there is still room for improvement
its been fun, i have made a few suggestions on stuff and watch the vehicle manufactures run with it
you may also be wondering why i posted this info on this forum
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pretty sure it will get out
started looking after i got a short video on my news feed of someone holding a cell phone in a meeting in a, im assuming mary barra office with 5 or 6 other people in view and some one asking if gm was looking into there own chips, something i had mentioned on this forum earlier. her response was that it was the tier companies to deal with.
and then it was gone and i couldnt bring it back up
took a few moments to process what i just saw and my first response was what the heck was that
should i feel horror that the internet is closing in on me
should i introduce myself to marry and say nice view out your window
nope, all i can think of, great another meeting:)
who ever did that, i like your sense of humor

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16,17 volt
1,242 Posts
Discussion Starter · #9 ·
so i will give you a couple ideas on how to fix it, 2 solutions will have to be from a smarter person than me and 1 that i know will work. last night i was even thinking, becouse the pwm power supply is controlled by the computer, it in itself could be affected by this, compounding the problem. for it, im usually 5 years behind technology, until it gets out to main stream and i get my hands on it, the volt being my point and case. the artificial intelligence out there is driving me crazy, the information that its providing me on this issue without me asking is second to none. I want it to stop, is the biggest reason, to me posting this. when i first started thinking about this i was focusing on the 5 volt computer data stream and how it was affecting it. more along the lines of the switching transition at 2 1/2 volts determinating whether it a data1 or a 0. seems like gm has gone beyond this and now the data streams are voltage referenced to the module. the main module knows witch module is talking buy the voltage it talks to it, so i module will talk at 10v , the next at 9v and so on
if thats the case , this will make this problem even worse.
first solution that i dont like, is speed up switching on the pwm power supply. that would be like chasing your tail as the data stream speeds up
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the second one is have 4 pwm that trigger one after the other to provide a constant voltage output
dont know if that could be done
what i do know will work is use a constant rpm inverter motor coupled to a alternator and use the output of the alternator to feed the 12v system
so thats my rant, enjoy your volt and if history repeats itself , i suspect ford will use this info first
you can lead a horse to water but you cant make it drink
before anyone truely understand what i just said
me dropping the mike
elvis has left the building

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ok can you please show us how to install this and where to buy it ( amazon link?)


Sure, but following in supchrgamx footsteps, some background. It all starts when I was a young boy ... :)
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Without spending a lot of keystrokes on this I have a few thoughts:
1) The internal impedance of the 12v battery even in a semi-discharged state is under 100 milliohms...very low with high dynamic current supply capacity.
2) The electrical circuits have decoupling capacitors on the voltage rails and voltage regulators for critical circuits that can regulate "brown outs" with ease.
3) I would suspect monitoring the 12v battery with a scope would only show low mV traces from various transients thus plenty of regulation.
4) The super capacitor would lower the effective impedance at the battery but would have minimal affect on the operation of the car's circuitry.
5) Super capacitors can be useful when monster hi-fi amps are used to play rap crap through monster speakers...special case not part of car design.

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2015 Red Volt
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Sure, but following in supchrgamx footsteps, some background. It all starts when I was a young boy ... :)
You ask some people what time it is and they tell you how to build a watch...:cool:

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I am getting my bcem changed . I also have a 2017 so prob my 12v battery needs changing. I also believe 12v could damage bcem.
So when I get my car back, I will:
Change the 12v battery
And was thinking of putting your set up to help protect bcem and other gismos.
Will your set up protect the bcem better since maybe next time bcem dies, i wont be on warranty!

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6,313 Posts
Aside: I monitor my Tesla 12v as there is more vampire drain going on (dashcam, fridge, etc) vs my GM Volts.

a) I monitor my Tesla's 12v battery using this always connected device:
Works fantastic and has "Ultra-low power consumption, average current: 1.0 mA"

b) I think my Tesla 12v is questionable. During a recent OTA update when the DC-to-DC is off for a short time, it dropped below 11v. The constant charging >14v has changed over the months as well as it use to be steady at ~13.3v.

Related article: Marine Battery Maintenance 101 - e Marine Systems
Multi-stage Battery Charging -- A typical 12-volt lead-acid battery must be taken to approximately 14.2-14.4 VDC before it is fully charged. (For 24 volt systems, double these figures.) If taken to a lesser voltage level, some of the sulfate deposits that form during discharge will remain on the plates. Over time, these deposits will cause a 200 amp-hour battery to act more like a 100 amp-hour battery, and battery life will be considerably shortened. Once fully charged, marine batteries should be held at a considerably lower voltage to maintain their charge - typically 13.2 to 13.4 volts. Higher voltage levels will "gas" the battery and boil off electrolyte, again shortening battery life.
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