But it would be nice to reduce the amount of PCBs that need to be wired together. Ideally everything would go onto one PCB.
Now I was wondering how hard it would be to do that.
Would it be possible to find the schematics for all (or most) of the PCBs and somehow merge them into one file and then just add a bunch of traces to connect them?
I guess I could use my multimeter and measure how all components of a PCB are wired up, but that would take way too long I think.
felic:
Now I was wondering how hard it would be to do that.
Very hard. And as you have to ask I'm quite sure it's impossible for you.
Especially with the high voltage AC output, low but still regulated 5V and 12V DC output, and other critical components. Not only does the layout of the respective PCBs matter big time, they are bound to affect one another if placed in the wrong way. The high currents involved add a lot to the overall complexity and expected interference.
Would it be possible to find the schematics for all (or most) of the PCBs and somehow merge them into one file and then just add a bunch of traces to connect them?
Yes. People go to engineering school for 3-4 years to learn how.
@wvmarie Yes, I think it is called galvanic isolation and I know that it is important. It shouldn't be that difficult to place the components on the PCB accordingly. Also, I think that the power bank would be way less prone to voltage fluctuation than your regular wall outlets. That should greatly reduce the odds of unwanted spark gaps etc. I think if I put the 110V AC stuff far away from the low voltage stuff and the traces are big enough, cables are thick enough and soldering is good there shouldn't be any problems with.
I'm pretty sure it's note "impossible" for me. But yeah it might be very complicated, that's why I asked.
felic:
Would it be possible to find the schematics for all (or most) of the PCBs and somehow merge them into one file and then just add a bunch of traces to connect them?
I guess I could use my multimeter and meassure how all components of a PCB are wired up, but that would take way too long I think.
Any thoughts?
Have you designed any similar PCBs before ?
And as an addition, how much electronics design experience do you have ?
Unless you want to etch the copper on your board yourself, you need a schematic capture program that will rout the traces for you. Please look at some of the ICs on the boards. Do they all have sockets? Of course not. So the board must have pads for the legs of the ICs to be soldered to. Look at the space between the pins. Once they get too close together, the board CANNOT be etched. Instead the copper is all etched away and the copper pattern is PLATED back onto the FR4 material. Etching undercuts the copper and leaves too little copper for fine-pitch ICs.
Once you are this far along, you need to have someone place the components onto the solder paste that is screened onto the board, and then all is run thru a convection oven to solder the components.
Learn what it means to "turn a board". It means the testing shows you made an error that cannot be corrected by cutting traces and adding wires. Many boards are turned several times before the engineer and the company is satisfied with the performance. ALL of the boards you are referencing have gone through this process. Your board will be no different.
@Paul_KD7HB I don't see me etching the PCB myself. Either I would use my PCB CNC (this would limit me to 2 layers) or if more layers are required, I'd simply get them made in China. I think it's like 5 bucks these days.
@srnet I have not designed anything similar before. I know how circuits work. But I couldn't design a functional inverter or variable CC step down converter from scratch without doing research first.
@wvmarle I meant the 110V AC should be galvanically isolated from all the DC components.
felic: @srnet I have not designed anything similar before. I know how circuits work. But I couldn't design a functional inverter or variable CC step down converter from scratch without doing research first.
The basic concept of using a large number of reclaimed lithium batteries in a power device intended for domestic use is complete madness in my view.
Your basically building an incendery device and a great deal of care and experience is needed to make it safe.
Boeing designed a similar unit, and despite using aircraft grade components, they got it spectacularly wrong, how many thousands of man years expereince did their engineers have I wonder .................
Well, I'm not putting other peoples lives at risk. Worst case I burn myself and destroy a device that I connect to the power bank. It's not like I'm putting it under by bed while it's charging. I have a special metal box for that. I also have no intention of using it indoors. When I transport it I can just disconnect the battery. The odds of an 18650 battery exploding while it's not even connected is near zero imo. Also, it's not like I'm not planning to test the power bank and pushing it to it's limits before actually using it. There are plenty of security features built-in. And besides that, Lithium fires are mostly just what you see in the media, 99% of the time it's just smoke. And reclaimed batteries would have an even lower risk of causing a fire because of they low capacity. And 18650s are much safer than flat LiPos.
Start by making a carrier board which supports and connects the modules you already have. Don't attempt to copy a switchmode power supply or something with a fine pitch IC.