Nevermind, questions answered. I dove head first into the research and damn these are gonna be massive chargers!
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I thought I knew how to adjust the voltage on these but after stupidly messing with all of the pots none of them controlled the voltage and I might have changed something about the PWM frequency…
some serious searching later and I can’t find instructions for how to change the voltage…
Good enough thing that I don’t actually need to raise the voltage of them at all, given that it is ~17.14S voltage max and I am using 16S.
I have come across something I am not sure how to solve.
The first issue I ran into is when series connecting 3+ power supplies without the AC ground isolated the fans will spin faster as more are connected.
I attempted to solve this by isolating the ground on all but one power supply.
This results in this from the LEDs:
The first negative light is off as well as the 5th in series.
This solution isn’t talked about by you @Agressivstreetlamp or in the videos I posted where they only hooked 2 up in series where this isn’t a problem.
I can see things online about how floating AC ground power supplies are unsafe and put voltage on the neutral wire. Idk if this is something that we are ignoring or what.
That’s as consise as I can write it I think.
What are you using these for lots of 12v in series?
These power supply converters
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These are high current server power supplies
110/ 240 to 12v.
Just wondering what your using them for or trying to achieve?
Mostly for high amperage lithium chargers.
But in general, to power the CC/CV power supplies linked up at the top. Which would then typically be used to juice a battery.
There are quite cheep DC to DC converters out there I use this one quite a high output and use a 12v server power supply, to supply it.
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These are comments on a video specifically about hp DSP-750s PD18
This person seems to have solved the issue by removing the wire on the back of the daughter board by the fan to the case. Worth a shot I guess. Makes sense to be because the fans were freaking out and this would remove the link from the fan to the AC ground.
https://www.rcgroups.com/forums/showthread.php?3137941-Converted-DPS-750-PSU-info_dump
In this forum thread people have similar issues without solutions
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This might have solved the fan issue, sort of, but I am concerned that it is only a band-aid that covers up a symptom of a larger and more serious issue.
Considering that lethal voltages are being messed with I personally would want to see some definitive (safe) solutions for all the issues without disconnecting things. Please be careful. 
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Just got done trying with the removed daughter board ground, now every other supply turned off.
I’m starting to think I really need to gave the first series power supply negative rail tied to ground for whatever reason. People say this doesn’t matter and you can leave one grounded or isolate all of them but it’s one of the few things different I am doing.
Maybe try putting cardboard between the chassis
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There is fishpaper on all of them as per the instructions.
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Has any of the videos discussed using an auto-transformer with the isolated neutral mod so everything floats? It’s what I use to keep AC-powered test instruments, like scopes, from blowing up when testing/measuring AC-powered products.
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Nope not a single one.
I am now case/DC to earth grounding one of the power supplies to see if this can get everything working properly.
Hey @b264 you are on this PCB
This supply isn’t DC isolated even though I modified it the same as all the other ones. Hmm
As I was suspecting, removing the screw on the daughter board solved this isolation issue.
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so yeah, removing the screw from the daughter board to the case completely isolates SOME of the power supplies. Others are totally DC isolated with this wire still attached. Taking a wild guess I think it has something to do with the jumper making them power on. I have no clue why
Guess I could give up and use all these for grow lights… in case this doesn’t work
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He dude sorry. So a couple things.
Usually the fans have a feedback loop that’s controlled off board. Meaning there is a separate logic pin that controls the speed of the fans. Often tying this to ground will reduce the fan speed (such is the case with those large dell 750 units i linked) to a non zero minimum, something like 10% of max…
For other psu without that feature i Personally i just let the fans run at full bore, or disconnect them altogether. That option is to simply disconnecting and removing the built in fans, and use the large case fans instead. However, some PSU will not start if the fan is disconnected. In this case it’s probably a good idea to just let them run full bore. It’s “just noise” and this whole build is based on a rough and tough solution to high power chargers. With effort, you can try to replace the fan with a dummy load such as a large power (10w) resistor. But don’t forget to cool things down with external fans otherwise the psu will go into thermal protection.
Connecting the lowest psu dc ground to ac ground is not a bad idea and might make your logic down.
As far as lethality is concerned i am houses to this a bit i guess but, just don’t touch them with your hands when they are on. Use your dmm to check any metal surfaces when it’s on and you’ll be ok. Even then, I’ve had my share of “shocks” and I’m still alive 
Sorry I’ve been mia. Hope this helps
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