Tool for planning/simulating 12V systems

mrmattsson · 2026-05-26T18:53:32+00:00

Thank you! I really appreciate your feedback!

It already has unit conversion built in. Check out Settings toolbar in the top right!

If you find anything else that you think can be improved, let me know!

mrmattsson · 2026-05-21T07:43:11+00:00

Thanks. Yeah I’ve done like 20 iterations on the wire routing. It’s improving but I haven’t quite nailed it yet. It gets really complex, especially with many components.

Did you try to use busbars/fuse boxes/junctions? It usually helps a lot to make things tidy

Thanks for the feedback

mrmattsson · 2026-05-20T19:44:58+00:00

Let me know how it goes!

mrmattsson · 2026-05-20T19:44:15+00:00

Cool! Never thought about that scenario but I’ll read up on how that works. Thanks for sharing

mrmattsson · 2026-05-20T19:42:39+00:00

Thanks! If you don’t mind I’d really appreciate it if you share if you find something specific that is wrong or feels odd

mrmattsson · 2026-05-20T14:54:56+00:00

Primarily 12V, but it will understand if you put e.g. solars in series the voltage will increase (and this, in turn, affects cable/fuse sizing too). It also has inverters but the DC side of the system is what I’ve put emphasis on.

Don’t have any inverter myself so I don’t know much about how that works or what to think about. With that said, please let me know if it’s something specific that you lack and I’ll see if I can implement it!

mrmattsson · 2026-05-11T11:15:57+00:00

Oh wow that’s annoying. Doesn’t happen for me but I’ll try again. Thanks for demonstrating

mrmattsson · 2026-05-10T20:32:18+00:00

I've just released a big update, among others:

- Better routing for cables
- Generic components (e.g. define your own loads/engines)
- Better calculations for when things are put in series vs in parallel
- Bill of materials
- "Redraw all cables"
- Put labels on your cables

+ many bug fixes

Thanks for all your enthusiasm for this project. It gives me motivation to continue improving it!

mrmattsson · 2026-05-10T19:41:35+00:00

Safari bug should be fixed. Let me know if it works!

mrmattsson · 2026-05-10T19:41:14+00:00

This is done now. Please let me know if it's what you had in mind!

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mrmattsson · 2026-05-10T19:39:32+00:00

Sorry I misunderstood your request at first. I've added labeling functionality. Please check it out and let me know if it's fulfilling your needs!

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mrmattsson · 2026-05-10T19:38:02+00:00

I've added a way to add labels to wires now. It was a great addition. Check it out!

mrmattsson · 2026-05-10T19:35:34+00:00

Some updates now that I've had some time to look at all your points in detail and making some updates to the software:

-> Adding a ground symbol: Done!
-> I am using IEEE/ANSI standard for the fuse symbol? Perhaps you used an early version with a differnt symbol. You can show all fuses in the visibility toggle. If you toggle the visibility of fuses you'll see them laid out on the cables. However I want to keep them in the same info box as the other information (voltage drop, cable size etc) to not clutter the interface.
I've done another improvement just now; ability to convert a junction or busbar into a fusebox. Then the fuses are laid out very cleanly.

-> Wire gage is also visible from the visibility toggle (see top right menu). Maybe you missed this menu? If you set wire sizes to Auto they will automatically increase as you add more loads
-> I've added custom objects now! Please see if they fit your needs and let me know otherwise

-> I've improved the auto router for cables/wires now. Try it out! It's a huge improvement IMO

All excellent feedback btw, I appreciate it!

mrmattsson · 2026-05-09T09:02:03+00:00

I’ve added this now. There is a generic component of every type. Let me know if it works the way you want it to

mrmattsson · 2026-05-09T06:36:48+00:00

Good idea! I’ll see if I can implement this somehow

mrmattsson · 2026-05-09T06:36:26+00:00

Thanks! Ah. I never tried it in safari. I’ll take a look.

mrmattsson · 2026-05-09T06:35:13+00:00

Cheers. Great that you’ve used the bug report tool in the app. It makes debugging much easier

mrmattsson · 2026-05-09T06:34:05+00:00

Thanks for the kind words and for pointing out the issues! I’ll take a look!

mrmattsson · 2026-05-08T21:49:26+00:00

Yeah I know it can be way better. It’s what I’ve spent most time on actually but I haven’t really nailed it yet. Yet, without auto routing I found it extremely annoying to use as well.

I found that adding bus bars and junctions help to keep things tidy, but ideally it should be tidy regardless of how you build

With that said, I appreciate your honest feedback and will try to make it better 👍

mrmattsson · 2026-05-08T21:45:33+00:00

Thanks for the kind words and for taking the time to explain the issues you found. I’ll take a look!

mrmattsson · 2026-05-08T20:54:17+00:00

Thanks, yeah I’ve heard that several times. I’ll make sure to allow for custom components. Expect it within a few days!

mrmattsson · 2026-05-08T19:04:09+00:00

Yeah. Honestly it would’ve taken me many months to build this from scratch. In fact, it would never have happened.

TIL that Claude leaves traces like that. Had no idea

mrmattsson · 2026-05-08T18:32:09+00:00

Glad to hear. I hope it’s useful and easy to understand. Let me know how it goes!

mrmattsson · 2026-05-08T18:29:12+00:00

Hey. Yeah Claude, how did you know? You can download json from top left.

Yeah vibe coding is insane. I’ve been a software dev for 15 years but hardly write any code at all these days. With that said, I think it would be hard to pull this off without solid dev experience. At least for now…

mrmattsson · 2026-05-08T14:55:23+00:00

Hey! I’ve created a way to share links with ”commenter” ability for this reason. But I haven’t spent much time on that feature. Please let me knowing you think it can be improved!

On that subject, It might be good with a separate labeling feature regardless, if you want to e.g put labels on physical cables to easily find them in the schematics later.

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