MacroUPS

A totally awesome uninterruptible power supply for high speed charging!

Created by NightshadeXD

Tier 2

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NightshadeXD submitted MacroUPS for ship review 3/17/2026 at 2:50 AM ago

NightshadeXD added to the journal 3/17/2026 at 2:09 AM ago

testing

ac problems

while testing the whole thing in general, after plugging in the ac switch again, i realized that the "live" led wasn't turning on, meaning that i either broke the psu, or something on the ac side popped

i got very scared for a moment since i thought i fried the psu, but after investigating with a multimeter, i realized that neither the live on the cheap aliexpress wire or the neutral on the aliexpress wire were connected, so i either pushed too much current through it or somehow disconnected it. well it made sense since it was like 2 dollars

luckily, i was able to get my hands on another wire with the same input and output, just that it was a bit dirty, but its fine, it works

battery problems

when testing, i also discovered that near full charge, the led would flicker and make an audible sound on the buck converter that charged the battery, which was not only ugly but also annoying as well as possible damage the battery? so i changed the voltage adj from 28.2v to 27.75v and it looks good now

once again, i ran into the battery flickering problem again, even after lowering the target voltage, but i dont really know if i can fix it, this is probably just a component issue. (at least its a lot less and stops quickly)

xl4015 modules ass

also, i felt the ic on that buck converter was scorching hot, even with a heatsink, reaching 200F! with my multimeter. remember my battery is only drawing fractions of an amp, so this is very unusual. i have also noted this problem earlier during testing, but its really bad, and i'm afraid it might melt my pla case for it. i also measured the other 2 buck converters. 130F for the cooling buck doing NOTHING and 105F for the usb a buck also doing nothing, so these modules are just really ass.

other stuff

another problem i have to fix is the output power delivery boards not being mounted well enough, since they wiggle back and forth when the line is tugged. i should tape them down or use standoffs to mount them (or maybe a 3d printed thing?)

also, i feel that the heat limit is far too high for the cooling module (40*C), which is probably unreachable in the spots i put the switch, since its too far away from the hot components, so i may have to change their locations.

a small issue here, but nonetheless: the box i used is slightly too short so the cap is wiggly when put on, which is only cosmetic.

final product images

top

front

NightshadeXD added to the journal 3/15/2026 at 11:41 PM ago

assembling 2

now i know at this point you're like wow you're probably almost done it'll probably only take you like 30 more minutes
wrong

anyways, you're basically right, we're almost done (according to the wiring diagram), but in reality we're not.

Here's a list of what we still have to do:

figure out where shunt goes
put in battery + wire that connects it
wire all the pd boards to the outputs
wire the cooling module to the output
tape the temperature sensors down to their targets

So the first thing I wanted to do was actually to get a minimum working version so I wouldn't fry any of my PD boards

external shunt resistor placement

Before we can actually figure out where it goes, I first stole this resistor from another extra XL4015 board. It is exact same resistance value so basically we are effectively having the current that it measures so we have to half our output as well.
next i had to figure out where the external shunt resistor would actually go. I talked about this in a previous journal entry where I mentioned that the current limiting for charging the battery wouldn't work properly because the grounds were connected externally. upon looking at my first idea, I realized it doesn't work because when I wired it up, I realized that it was still way over the current limit and the reason this was because i placed the shunt in between the battery gnd and the buck module, so it wouldnt really work to half the current
I fixed this by placing it after the battery output. however this means during battery load all the current has to flow through this shunt resistor. it will work but it will generate lots of heat so I might have to put a heatsink on this later. After testing this new solution I figured that it works and now the car is properly being measured at right under an amp.
Of course the easiest solution to this problem would actually just to change the buck converter topology entirely, instead of using low side sensing we would use high side sensing so the ground will all be common, which will increase efficiency and make it a lot less painful to route
new shunt placement highlighted in dark blue

wiring pd boards

So initially for the power delivery boards I was expecting them to all be soldered together into one giant bundle then solder this onto the 14 AWG wire for the output

But when I had all the modules taped down and in their position I realized that this was not going to work at all since there were actually six whole wires that I had to solder together. So the next best thing I did was I took one of my extra terminal blocks that I was supposed to use for the ideal diode module and then I took this terminal block and I just put all the wires inside of it. initially I didn't have anything that connected the two terminals but then I decided the best way to do it was to solder a wire under it on the through hole connections and I actually decided to use two 24 AWG wires to maximize current capacity.

But then sometime around this point I was having more trouble with the schematic because if I was wondering if all the grounds are connected with that like short something out or cause current to flow specific Direction like what if there's different potentials on the battery negative and the power supply negative or something. Anyways I was pretty sure that was wrong

battery test

then I put the battery inside of the case to test out my first test (with one pd board only) by hooking up the battery with alligator clips. I actually have a specific rationale for using alligator clips because I thought that soldering wires to the battery could damage it and break it for future use. if I just use alligator clips it should provide like enough current handling capacity while also providing a little bit of insulation.
the test honestly went great, i was really happy nothing blew up :)

cooling + more battery stuff

Also it was around this time also began thinking about wiring up the cooling modules's output I simply just had to link in the wire and I did this by our soldering on like two red wires together and I just connected to the output

then after this I connected it with the wires as well as the amazing battery voltage meter and then after doing all this I put the temperature sensor one on the battery and one on the power supply

NightshadeXD added to the journal 3/15/2026 at 7:57 PM ago

assembling

i spent most of 2 days doing all of this
Now that we have all the modules that we need, we can begin to assemble it and put everything into that little box of ours. Right now, all the wires are from the cooling system, and it was very messy.

The first thing I did was to put in all of the usb pd boards (outputs) for some reason. (idk why i thought that at the time)

anyways, i just shoved all the modules into the box, and wired them up. they were just left kinda hanging in the air by the wires. i followed the schematic exactly so far (not considering the shunt resistor needed yet - we'll get to that later)
eventually, i couldn't take it anymore, and i had to resort to wire management.

i taped down some loose wires to the ground and walls. (especially for the cooling section since it had very long wires)
i also taped down the power supply.

but first, im going to rant about how ass these wires i used were. i found a box of 22 (or 24?) awg wires in my house, and these were meant for breadboards but whatever. i soldered them onto each other to make a longer wire, but they still sucked. these wires broke left and right i'm not even kidding. the wires connected to the pd boards broke so many times, and i have to take it off, resolder, put it back on every time. not just there, but also to BOTH leds they broke just just took up so much time.

most of the modules were wired up at this point, so i had to remove some wires, then tape the modules down to the bottom of the case (with my thermal tape since its double sided). then, i rewired them and i think it looks 10x better!
At this point it looked somewhat like this. i know it probably still looks awful to a lot of you guys, but i promise its like 10x neater than before.

NightshadeXD added to the journal 3/15/2026 at 7:47 PM ago

ordered new parts

So first I designed a new ideal diode pcb.
This new pcb has:

ground pours
larger pours for the vin and vout
fixed drain + source orientation
larger caps for easier soldering I spent some of my own money to get the ideal diode parts + new pcb.

It took a few weeks to arrive, but when i got it, i began soldering (since I didn't order it with assembly)

All i needed for this project was 3 working ideal diodes.

and you would not believe how difficult it was to solder ts. the lm74700 is just a pain to solder. not only that, my pinecil tip was straight ass, since the solder wouldn't stick to it, only ball up on one side since i think it oxidized, and with no sponge or brass wool to clean it, i had to do the best i could like this. (with a wet paper towel)

the first module i kept bridging the pins, and to remove the extra solder, i didn't have any solder wick, so i had to desolder it and resolder it completely. even then, after making all the pins touch correctly, when i checked continutity with my multimeter, ground wasn't fucking touching even though the pad was, which meant i probably lifted the trace. so i had to scratch a bit of the soldermask off to connect straight to the copper, but then i bridged the pins again and gave up on it

the second module i tried went better, but it was still hard to solder the lm74700, the rest went alright
the third module went the same,
the fourth and final module i fucked up somehow. it was by far the best looking module (in terms of how aligned the components were). and i thought it was perfect but when testing, i realized it had a whole 0.5V voltage drop across the mosfet?? - my first idea was that the lm74700 wasn't connecting at some point, but a few continutity tests proved otherwise. after a few more tests, i realized that i probably just fried the chip. 🥀 even though i barely touched it compared to the first module.

i just settled with these 3 modules since i was running out of time and patience. Also, we don't need the lm74700 for the module to be a diode, just for it to be an "ideal diode", so i chose to this "faulty" module as the diode for the battery charging part, since it handles the least current (1a usually).

Here is an overview of the tests i did on the modules, the voltage drop is very impressive

I know the time on this may seem like a stretch, but i promise, i spent a good 4 hours redesigning the pcb + picking parts, ordering, then a good 2 days to solder everything together. This was by far the most awful part yet.

NightshadeXD added to the journal 2/16/2026 at 4:30 PM ago

ideal diode :(

you may have noticed there's been a lapse in progress, bc of this:

So today the ideal diodes arrived, and i tested them!! (one at least)

so here's what i've got so far:

Using a 9v battery (8.92V), the voltage drop (no load) was only 22.1mV!!!
at 0.15A it only went up to 22.5mV

soon i'll test reverse voltage and also higher amperage

well, i tested reverse voltage, and guess what, it didn't work, it just acted as a normal diode with 0.7v drop the wrong way

it took me like 2 seconds to figure out that i flipped the mosfet direction like a bum and now i have to reorder it from jlcpcb
yeah thats more money from my own pocket
this time i just ordered pcbs and parts from lcsc and i'm going to solder them myself at home (hopefully i dont break anything)

so, in the meantime, i went outside, set up my soldering iron, and tried to desolder the ones i have right now, but i just can't without the soldering wick thingy

NightshadeXD added to the journal 1/30/2026 at 3:24 AM ago

cut out usb holes

did this over past few days.
it was a pain in the ass

I measured it out and tried to keep it as aligned as possible

For usb a:
I did it by drilling holes then box cutting it out, this sucked and i made a few small cracks, but it got the job done. i also found a nail file and filed it down to widen it

for usb c:
i started by doing the same thing as usb a, but then i switched to usin ga bit to drill out the two holes on the sides of the usb, then connecting it + widening it with a slightly larger bit + filing it to widen it

end result:

this sucked since the plastic was so hard but i got it done honestly it took so long bc of procrastination.

however, i made 2 oopsies during this (that i've noticed):

I accidentally broke one of those fragile ass wires soldered to the usb-a stuff and I'll have to solder a new wire onto it
The usb a module is too close to another one. I can fix this either by: cutting off a chunk of the green module OR moving it apart which i dont want to do idk really its not a huge issue but whatever

TODO: put some text labels onto the front

NightshadeXD added to the journal 1/26/2026 at 6:01 PM ago

stuff this weekend

saturday

I spent the majority of the day working on it,

fans

drilled out new holes for the fans, since old ones were misaligned, and used some vex iq pins to mount it (they fit really nicely and are tight so i probably wont change it)

power led

so I opened up the mean well power supply to see what was inside and to also solder up the power led

im going to be honest the mean well fan was so annoying to screw back in
also had to make sure the the leds would work in parallel. they did, but the outside one was a little dim, but fine
I had to solder 3 wires together to reach the hole for the led since it was so far away but it worked.

breaking stuff

so when i was testing, i was trying to probe the ac lines for voltage to make sure that they were working fine. i touched the com of my multimeter to the psu neutral (ac), and there was a huge ass spark then the mean well turned off. it left a black marking on the neutral screw terminal and melted the tip of my probe.
i spent the next hour trying to figure out what happened, but i couldn't get a clear answer.
when I plugged it in again, it wouldn't turn on. luckily, this was bc i tripped the breaker, not broke the mean well. i resetted it, and it worked fine again
I made sure to double check ac wiring and stuff but I'm still confident that it is right

sunday

printing stuff

so i cleaned 3d printer build plate, and this fixed most of the issues
I printed out a few things:

some screws + nuts that didnt have tight enough tolerances
some cases for the xl4015, since the power supply case was grounded, and the pla would insulate it in case the xl4015 touched the power supply
more screws that were supposed to mount the l4015 to the case but were too tiny
clips that were too big

battery

battery still seems fine, despite the negative reviews
I don't really want to solder anything onto the f2 terminals, since it might damage the itnernals from heat, so i tried printing clips to hold wires onto it, but they were too big to fit. I might just cut off the top of an alligator clip

also I measured the voltmeter current draw. its ~8mA when on, ~2 when screen off (idk why so high). the voltmeter also isn't very accurate for the lifepo4 battery since most of its discharge curve is flat, and it relies on voltage to tell capacity (with 0.1v precision)

basically flat so 60% and 40% look the same

fuse stuff

on the main 15a fuse, i soldered the other side: a small wire to charge battery (max 1.5a) and a large wire that will supply current from the outlet when power is on. (10-15a)
![image](/user-attachments/blobs/proxy/eyJfcmFpbHMiOnsiZGF0YSI6OTIwOTEsInB1ciI6ImJsb2JfaWQifX0=--41110b1057172c3d970a58e81e90a9916eacfac1/image.png

honestly just waiting for the ideal diode modules to arrive then i can finish it

State rn:

NightshadeXD added to the journal 1/22/2026 at 2:26 AM ago

uh oh

today i did a lot of thinking, and i corrected the wiring diagram:

the battery level indicator already has a on off switch, so the other one unnessary
added ground connectiosn
the fan wiring was wrong (oops)

BUT THEN, i saw it
this is bad

the problem:
for cc to work on the xl4015, you CANNOT tie in- and out- together, otherwise, cc breaks since nothing flows thru its shunt resistor.
now this is bad, since we MUST have cc for battery charging.

the solution:
i spent a good hour researching and thinking up solutions
heres what i thought of:

diode on ground
mosfets
ic/mcu
resistors
a different buck converter
decidated charger

i think i've found a solution, which is to put a resistor on ground the same as the shunt resistor and then we can double the cc value since half flows through the xl4015 shunt, and half goes through my external shunt. i think this'll work even tho its chopped

NightshadeXD added to the journal 1/20/2026 at 3:31 AM ago

case, + a bunch of random thingies

Today I did a lot of things, since there was no school for me

tested out battery charging

basically the title. this was scary, since the battery was 40$, the most expensive part of the project.
I hooked up the xl4015 to the battery, and it seemed to work fine. I noticed that the battery only drew about 0.8A at the start, when the CC limit was 1.5A.
However, I did have issues where the xl4015 would go into cv before it even reached the target voltage?? also, i noticed fluctuations in current when the battery was reaching its charge goal (like it would bounce around a lot from 0.05A - 0.3A). I also hooked up the battery monitor thing to the battery, and I guess it works fine.

also testing the 65 watt charger

so this charger I plugged into my laptop with a wattage sensing cable. when it was 65w, it heated up significantly, so I added 4 heatsinks on it

the case

so instead of 3d printing it, since it would be far too big for my tiny a1 mini, i spent half an hour searching for a plastic box that would work. Then, i spent the next 3 hours of my life painstakingly cutting out the box to match the cad. the box felt like polycarb and was basically impossible to work with.
I even used a drill and it took forever to get a hole through, and even worse was cutting things out:
I first tried using a box knife, but it kept making cracks in the box and barely made a dent otherwise. I switched to a drill, using it as a cutter, but this sucked and it make microplastic dust. then i just tried normal scissors, but they kept bending. :( I ended up using scissors and the drill to cut everything out.

I cut out:

2 led holes
the the front battery indicator (this probably took a whole hour alone)
fan screw holes + the actual fan hole
the small kcd3 switch hole
the c14 panel + screw holes

todo:

all the painfully accurate usb c and usb a ports

also, the box is a little too low, which will making putting on the top look bad

ordering the ideal diode

I haven't mentioned this in any journal yet, but for some reason, I didn't have enough money to get the ideal diodes, probably since I added the 2 terminal blocks, and they took back the 3$ shipping discount fsr
So I got the money today, and I checked it one last time and ordered it.

ac soldering

after cutting everything out of the box, i had to finish soldering the kcd3 switch to the c14 panel (since i couldn't when it was outside of the box).
this was particularly difficult since it was in a corner of the box, but i managed to get it done.

more fans

in the afternoon, I put my chopped fan setup into the box, and soldered some wires together there, and tested to make sure it works.
I also soldered the LED for the fans and everything works now.

screwing around

so to attach the fans (and the c14 panel), I needed some screws. now this wouldn't be too bad if i had screws. but i dont. so i have to 3d print them.
so i began printing, but I just couldn't, for the life of me, get a single print to stick to the print bed enough to print out a screw
i only managed to get a few working nuts and 1 working screw that was too short out of like 20 attempts.

this is supposed to be a screw btw 💀

fusing the fuses

soldered the 10a and 15a fuses, attached the 15a fuse right to the power supply

testing more parts

so in the morning i tested battery + 65w charger, but i never tested battery drain. i hooked up the 65w charger to the battery and began measuring current draw with my multimeter.
It draws a little over 3A on 65W, and about 0.5A on my phone (probably 12-15W).
i also noticed, for some reason, when on my phone the output current jumps around a lot (about 0.1A jumps).
anyways, the battery held up pretty well

NightshadeXD added to the journal 1/19/2026 at 3:30 AM ago

stuff i did today

battery stuff

i did a little testing with the battery, and i found that the voltage seems fine.
also i played with the battery monitor thing, it seems to work fine - i'll have to solder it on later or use some sort of terminal mount
i hope it doesn't die on me like the other people who bought this 3.8 rated battery

to charge the battery, i'm using a xl4015 (like said).
i hooked it up to my power supply unit and adjusted current + voltage to 28.4V and 1.5A with a multimeter, which is under the 75W limit but will still need a heatsink.
haven't tried charging yet

fans

so I started doing the fans, but I never really got to finish because it's hard to know how to solder the wires and the lengths without the case but i:

got buck converter tuned to 12v
tested both fans
tested the temp sensors on + off
soldered the led + resistors for the fan (2x1k ohm resistors in parallel = 500 ohm 0.5W)
did a bit more soldering to prepare for final product

usb-a (w/o pd)

I also did half the usb a section

tuned the buck converter, found the best was 5.2V,
tested voltage drop when 2 devices were on at once, made sure it worked. However, I noticed that voltage sags to 4.75V when there a lot of load on it, but this is probably normal.

misc

did the mains led soldering (needed 4x 10k resistors in parallel) - uses about 1w
- the mean well has a built in led on it, i may unsolder it and then attach long wires to "extend" it, this way i save some wattage
put a heatsink with my thermal tape on 3 xl4015 buck converters
tested cables, and the usb c power delivery which we haven't gotten to yet.

problem: so a lot of this project is depedent on the case its in, and i haven't gotten to printing one yet. my a1 mini is too small to print the thing i designed, so i realistically have 3 options

print in separate pieces, attach later (probably the smartest)
find a random plastic box then drill holes in it (easy to do, just as good honestly except for wasting my life on cad)
ask someone else with a huge printer to do it, prolly not gonna do this bc who and its going to be huge to ship and probably break

NightshadeXD added to the journal 1/18/2026 at 7:09 PM ago

buying things + a lotta soldering

so theres a few problems:

i dont have the ideal diode module yet
i dont have the case since my 3d printer is way too small
and im missing a buncha things, so i researched some products and bought them:
- actual solder - 12 dollars :(
- thermal glue / tape for the small heatsinks that i thought would come with it -7 dollars :(
- electrical tape / heat shrink -6 dollars :(
- so i bought all of that

without knowing exactly where each thing would go, i simply soldered some wires onto the components. :)
I managed to find some random wires at my house, and i just put them on the things i needed with help from my little brother - also this is like my 2nd time really touching a soldering iron so it wont look that great

in case you want to know what i soldered:

the ac input:
- c14 socket
- switch
all of the power delivery things
- usb c 65, 45, 30, 30
- usb a pd, 2x usb a normal
thermal switches (3x)

a	b

note on the time:
these 11 hours were everything from researching the products, learning how to solder, preparing the items to solder and setting the things up, and everything from the past like 2 days

NightshadeXD added to the journal 1/18/2026 at 3:03 AM ago

i completely redid the ideal diode module since i was scared

the title, basically

technically this shoudl have counted as design but i dont know what to do
so before the module was tiny asf
now i make it bigg
so better heat dissipation ig
also terminal blocks that take 24a now, which is better i suppose
i pray i didnt fry anything and that it'll work when it gets here

uploaded to github as v2 of ideal diode
image:

NightshadeXD added to the journal 1/17/2026 at 1:59 AM ago

Got the parts!!

i got the parts! then i unpackaged them and took some lovely photos
(except for the ideal diode module) - im still trying to make sure that everything is right

I believe I've got all the parts I ordered, just trying to make sure everything works.

A picture of all the parts

Iamalive 🚀 approved MacroUPS 1/4/2026 at 1:34 PM ago

Tier approved: 2

Grant approved: $199.00

Great work man, congrats on getting out of reviewing hell :)

NightshadeXD submitted MacroUPS for ship review 1/1/2026 at 3:43 AM ago

NightshadeXD added to the journal 1/1/2026 at 3:34 AM ago

no more pigtail wires + cad

I found these 2 parts on ali (c13/c14 cable + mount) that would effectively replace the current pigtail wire

1x of Power Supply Cable 3-Prong 1.2m, TYPE USA, PRICE $3.49
1x of IEC320 C14/C13 Panel Socket, TYPE Type 4/China Mainland, PRICE $1.33

This should replace:

1x of US Power Cord 3 Prong 18AWG 6ft, TYPE N/A: link – PRICE $8.99

This is good for 2 reasons:

It saves money (obviously)
It's easier to use since it's compatible with more things and you can just unplug it and replug it into other compatible devices.

Uh and also I have to update the cad to include a mount for the panel, sucked. And honestly I dont even know if these measurements are at all reliable. Also I "polished it a little" if you count rounding the edges and adjusting placement a little.

And I decided to take the liberty to update the wiring diagram for a more easily understood ac side, since I have mostly neglected that.

And of course, we need to update the github's CAD, readme and BOM istg tspmo i dont want to do this ever again

NightshadeXD added to the journal 1/1/2026 at 2:58 AM ago

cost optimizations, better journals, readme

arghhh iamalive promised me it would be the last one

But yeah the parts are mostly optimized already. Aliexpress doesn't have many batteries at the specs I want, and if they do, its more expensive. Also, ali doesn't have high quality power supplies at the price I have it for. For wires, they are about the same, but its more high quality from amazon I think. For the pigtail cable, I couldn't find any on aliexpress, but I'm considering switching to C13/C14 cables since its more versatile and cheaper from ali.

Also I updated some of my longer journals to have more info on what I did or adjusted the time spent.

Readme was improved: I added motivation + specs

Tanuki Tanuki ⚡🚀 requested changes for MacroUPS 12/30/2025 at 10:48 PM ago

Hey! from what im looking at, I think that there should be more in each journal to justify the amount of time spent. Im seeing up to 9 hours for some! I also think the CAD can have some more polish. The readme should also be more descriptive; this feels a little hard to understand right now. Can some of these be cheaper from aliexpress? Thank you!

NightshadeXD submitted MacroUPS for ship review 12/23/2025 at 8:48 PM ago

NightshadeXD added to the journal 12/23/2025 at 8:47 PM ago

what

i think i did it right
tryna figure out what theyre trying to get me to do here
like unzip the gerber? because i dont know what other pcb files i can include
well i did that

Iamalive 🚀 requested changes for MacroUPS 12/23/2025 at 8:32 PM ago

Wait this time for real last thing - include your pcb files in your repo! If its in a zip, individually include the files instead.

NightshadeXD submitted MacroUPS for ship review 12/23/2025 at 8:29 PM ago

NightshadeXD added to the journal 12/23/2025 at 8:28 PM ago

Organized repo

I organized repo into folders:

CAD
Ideal Diode
images
misc

sjfoapefjasopfeijasopfjskdmfaopfaospiejfspoefjsoieffosjjfj
CAD image idk what else to put

Iamalive 🚀 requested changes for MacroUPS 12/23/2025 at 8:11 PM ago

Just one last thing - please organize your repo so its split into folders - like images, cad, pcb, etc.

NightshadeXD submitted MacroUPS for ship review 12/23/2025 at 7:48 PM ago

NightshadeXD added to the journal 12/23/2025 at 7:47 PM ago

Uploaded .step CAD + Added BOM Prices

Updated the Github repo with the .step file of the CAD.
Got all prices from the carts and added it to the .README and the BOM.csv. :)

Random Image:

Iamalive 🚀 requested changes for MacroUPS 12/23/2025 at 7:01 PM ago

Please include prices in your BOM, as well as change your cad model to a .step file.

NightshadeXD submitted MacroUPS for ship review 12/23/2025 at 5:20 PM ago

NightshadeXD added to the journal 12/23/2025 at 4:33 PM ago

Improved ideal diode PCB + Found new battery

I added vias under the MOSFET for improved heat dissipation, along with a copper pour on the opposite side which would benefit cooling.
I also updated the github with the new gerbers, pickandplace, bom, and source files.
Updated the github README with my schematic, pcb, and render images.
Also added the source files to the README.
Original battery went out of stock, so I spent some time looking for an alternative with the same voltage and capacity. I found this. Added to the readme.
Updated BOM.csv in the github

New Ideal Diode Schematic:

New 3D Ideal Diode:

zsharpminor requested changes for MacroUPS 12/22/2025 at 10:50 PM ago

It appears that you're planning on using a PCB (you have Gerbers and pick and places) but you have no images of your PCB schematic or design in your README, as well as no source files from your PCB design software. Could you please add these? Additionally, what did you change from the last review?

NightshadeXD submitted MacroUPS for ship review 12/18/2025 at 10:41 PM ago

NightshadeXD added to the journal 12/18/2025 at 3:04 AM ago

final adjustments updated

reviewer person please dont send this back

Parts List (updated)

Power

1x of 14awg Wire 30ft, TYPE 15ft 14awg: link
1x of US Power Cord 3 Prong 18AWG 6ft, TYPE N/A: link
1x of 24V 7Ah LiFePO4 Rechargeable Battery with BMS, TYPE 24V / 7Ah: link
1x of MEAN WELL LRS-350-24, TYPE N/A: link

Power Delivery

1x of PD65W fast charging module (Type-C), TYPE 4pcs: link
1x of PD45W fast charging module (Type-C), TYPE 45W: link
2x of PD30W fast charging module (Type-C), TYPE 30W: link
1x of USB-A breakout female board, TYPE 5PCS: link
1x of USB-A QC2.0/3.0 buck converter module, TYPE 2 Channel: link
4x of 120W USB-C to USB-C fast charging cable, TYPE Black C-C/2m: link
4x of 120W USB-C to USB-A fast charging cable, TYPE Black A-C/2m: link

Modules

1x of DC-DC adjustable buck converter XL4015, TYPE HW-083B 4pcs: link
1x of Battery capacity indicator voltmeter, TYPE Color Screen/CHINA: link

The Custom Ideal Diode Module (3x)

Check the github for specific BOM, gerber, pickandplace, as well as source files + images.

Switches + Fuses

1x of Rocker switch ON-OFF, TYPE Red 2Pin: link
2x of SPST waterproof toggle switch, TYPE N/A: link
2x of Circuit breaker switch fuse, TYPE 10A/Other: link
1x of Circuit breaker switch fuse, TYPE 15A/Other: link

Cooling

2x of 12v DC cooling fan, TYPE 8025/12V: link
3x of Thermal switch temperature sensor 40C/H, TYPE 40C/H (Normally Open): link
1x of Aluminum heatsink 15x15x15mm, TYPE 15x15x15mm: link

Wiring Diagram Changes

I swapped the order of the battery charger with the ideal diode since I figured that reverse flow when the battery is on might hurt the charger module.
Also decided that the 266W was too generous for the battery to supply, especially with the inefficiencies of the fans and voltage drop (250W left). To solve this, I decided to use 2 standard USB-A ports with a buck converter (low power 7.5W with shorted D+ and D- pins) + a 2-channel high-power one. This replaced the 4-channel high-power. This left me with 233W, which is under the 250W cap.

Cad

Updated the entire GitHub's wiring diagram, CAD and BOM. (Plus the ideal diode BOM, gerber, and pickandplace)

NightshadeXD added to the journal 12/18/2025 at 2:15 AM ago

Routed the PCB

Now it's time to route, I personally think this is the fun part of a PCB.
Anyways heres what I did:

Here’s what I did:

First, I placed the components near each other and started routing according to my schematic.
I had to make sure to put the anode and cathode on the MOSFET side instead of far away, since high-current traces will cause voltage drops.
Then, I wired the MOSFET to the IC with the charge capacitor.
Next, I needed to connect the MOSFET to VIN and VOUT. I initially tried thick traces, but they were hard to work with and not very effective. So I switched to a filled copper region.
At first, I did it on one side only, but then I realized doubling the layers halves the resistance and doubles the max current. I copied the fill to the other side and added a bunch of vias to connect them. This way, I reduced voltage drop and increased current capacity.
Finally, I optimized the board size and spacing a bit.

I was really happy I managed to fit this entire board on an extremely small footprint (15.87mm x 12.35 mm)

3d Model:

Schematic:

NightshadeXD added to the journal 12/17/2025 at 11:47 PM ago

schematicking

Yeah now I gotta schematic it. Adding the parts wasn't too hard because I already got the part numbers :)

Then I had to wire it up, and this was horrific.

I had to dig through the LM74700 datasheet, and it was pretty bad since like half the stuff I didn't understand, but I managed to find some useful info on how to wire it. This diagram helped the most:

I thought it was weird that the mosfet labels felt flipped (drain and source). I ended up just following TI's schematic to figure it out.

Also, it was really hard for me to figure out the charge pump capacitor setup. They didn't provide an exact capacitance, but I found here that it had to be 10x the value of Ciss of the MOSFET used. After a few more calculations, I found 100nF would work well, since it was well over 10x the Ciss of the AGM MOSFET (about 5nF).

Also I added smoothing capacitors because the minimum amount of capacitors that I could order was 20 and 3 per moudles * moudles gets the same cost + more functionality.

This was my final result:

NightshadeXD added to the journal 12/17/2025 at 11:05 PM ago

Figuring what parts to use

Now I gotta figure out what to actually use for the ideal diode.

I started by researching the original chip I planned to use, the LM74610. About ~2% of the time, this chip's output voltage drops a good half volt while it recharges its capacitor because it’s groundless (it needs to drive the MOSFET gate above the source).
That's bad because if the voltage drops, the OR-ing circuit downstream might think the mains line is lower than the battery line and switch over repeatedly over and over. That would happen every like half second which is not great for longevity. I'd also rather not make downstream components deal with a ~0.5V drop every half second.

So I decided to use a different chip that doesn't have this annoying voltage drop every half second. I settled on the LM74700, since it’s grounded and supports 100% duty cycle operation according to this guy.

That fixes one problem, but now the hard part is choosing the MOSFET, since it requires an external N-channel MOSFET.

I first found the CSD18534Q5A, which has a decent RDS(on) of about 7.8 mΩ. At ~15A continuous, that gives around a 0.12V drop. That’s acceptable, but I was aiming for closer to 0.05V, like the prebuilt module I found online.
I kept searching and even considered paralleling them, but most options were either out of stock or had too high RDS(on). (also quite expensive for what I wanted) Eventually, I checked what the actual module was using and found they used the AGM403A1. And guess what, it's like a good 3x cheaper and has an RDS(on) of around 2.7 mΩ like holy cow!

So yeah theres 3 hours of my life down the drain. And also i should be studying for finals instead of doing this

what do you want me to put, an image of the ideal diode module???
Dog:

NightshadeXD added to the journal 12/17/2025 at 10:53 PM ago

Deciding what to do

So the reviews keep telling me that my project isnt good enough so now i need to decide what to do to make the project more vcomplex w
I first thought about designing a custom power supply, but that means dealing with AC, which I don’t want to touch because nobody likes to get electrocuted. After looking into it, it’s also way harder than I expected like my brain is far too tiny for whatever those engineers are doing.

So I thought of a few other ideas:

Use a microcontroller to control fan curves and measure battery voltage/current.
Design something from scratch, like an ideal diode.

So, I decided to design an ideal diode from scratch.

Dog:

zsharpminor requested changes for MacroUPS 12/15/2025 at 1:23 AM ago

Hi, I really like this project, but is there any way for you to either reduce the grant and make it a Tier 3 or to add complexity (maybe make a fully custom PCb that handles power supply) for a Tier 2? Also, you need an image of how your parts are gonna fit together as well as a BOM.csv file, thanks! Finally, we need your FULL cart screenshot to see what exactly you're buying.

NightshadeXD submitted MacroUPS for ship review 12/15/2025 at 12:58 AM ago

NightshadeXD added to the journal 12/15/2025 at 12:37 AM ago

Updated parts list + github edits

I created the new parts list and edited the github repo.
Edit: New parts list is organized into specific categories and has better selection of parts, as well as the amazon links I forgot earlier.
The GitHub repo now contains the CAD, wiring diagram and parts.