Hmm allright. The power saving isn’t that significant so perhaps I should find a better way for it.

If the house burns down because of that your insurer will likely be difficult about it. You should also check the policy of your insurer, perhaps the cause of the fire is irrelevant.

As for fire safety. I always put my electronics in non flammable environments and make sure that everything is fused with either a current or thermal fuse.

Anything with high current consumption goes inside a metal box so that even if it does catch fire it can’t take anything with it. 3D printed enclosures are fine if you mount those inside a metal bucket for example.

Thanks. Haha no I fully intend to grow vegetables. I don’t even like weed. The last time I smoked it eas 20 years ago, it gave me a panic attack and I never touched it since.

For my use case fidelity is no problem at all. My spot size is minimally about 0.1mm and I’ve increased it to 0.5mm to increase speed.

For photosensitive dry film you don’t need much power so you don’t need max focus. In fact you’re likely to burn through the film with the smallest spot size.

Toner transfer has been messy and unpredictable for me. Also alignment with double-sided PCBs is more difficult this way.

That is a good point. I was under the impression that solder mask is mostly for safety and convenience when soldering so it only flows where you want it to.

Creating a mask that works for solder mask as etch resist does require some tweaking with the SVG files. I’ll give it a try for a few small boards to see how well it really works.

Why is that? I understand there is a tiny layer of exposed copper on the side of the traces but copper tends to form a protective layer of oxide.

Tooting my own horn. I have something to add. With the UV “Mechanic” solder mask that gets sold on Chinese webshops pre-heating the solder mask makes a HUGE difference. Apparently it contains some volatile components that interfere with the curing process.

Heating it to about 80-ish C for a few minutes and optionally letting it cool down causes the laser to almost instantly cure the mask. Any non-exposed mask will be easily washed off with some IPA.

Yes that I found as well but have/had trouble understanding why it would be built like this. Also why a MOSFET would be designed internally like this. If you want more power capability you’d get a bigger MOSFET rather than two tiny ones in parallel right?

This page helped me understand the setup. I’ll post it here just for informational purpose. It took me a while to find this. https://electronics.stackexchange.com/questions/203463/dual-mosfet-8205a-lithium-battery-protection-circuit

It’s related to the internal body diode of the N channel mosfet, so two of them are in series but reversed. When one MOSFET is activated, current may flow easily in one direction but be reduced by the body diode of the other. When both are activated, current may flow easily in either direction.

It seems they don’t really prevent discharging or charging separately due to the body diodes but they can cut off the battery alltogether.

That’s good. My switching frequency is a few times per hour.

I am a little bit concerned that the slow rise/fall time make the MOSFET go outside its operating parameters for a fraction of a second. The resistance gradually changes meaning the mosfet will dissipate more power but also less current will flow.

So if you switch many times per second the gate capacitance with the resistor acts as a low pass filter reducing the gate voltage.

Replying to myself for informational reason. Modifying voltage was more or less successful. Both optocouplers transmit a reference voltage, so both need to be adjusted simultaneously.

This can be done by changing the value of R19, a 23.2k smd resistor close to the output terminals.

I’ve attached a 10k pot with a 10k and 6.8k resistor in series and successfully modified the voltage down to 22.5.

The power supply itself is a piece of crap though. It claims to handle 400W but anything over 150W causes the short circuit protection to activate, never mind overheating at 150W very quickly.

Well there certainly is some regulation because attaching a load does not decrease the voltage by much. Increasing the voltage is indeed ambitious for the 12V model but lowering the voltage of the 12V model seems doable.

Thanks. I ordered the 24V model in hopes of adjusting it down to 22V. I will use that to keep a 7s Li-Ion battery at a minimum charge level whereas a solar panel array may increase that voltage higher. It looks like the 24V model’s capacitors need to be changed as well since they can’t handle the Li-Ion batterys’ max charge voltage.

Yeah don’t worry about it. Running a fan at a lower voltage than it’s meant for will result in slower fan speeds and a longer lifetime. Compared to the wattage an actual laptop will draw this is absolutely nothing. I power my soldering iron with an old laptop charger without issues.

Those plugs are generally used in 12V systems but they can handle higher voltages too. It’s the current you need to be mindful of for the most part, they can overheat if you try to power a space heater or something from that but a few fans won’t cause any issues.

Where is the video? Electroboom craziness sounds entertaining.

Those 5400mWh batteries are a scam. Be very careful with them.

Well the copper should disperse the heat fairly quickly. It should be okay.

Whatever you do, keep it away from anything flammable or near any living environment.

If electronics stores are not willing to help you could try the fire brigade. Call them on the non emergency number. They can advise you much better.

Right that makes sense. I don’t know how much faith to put in fair trade labels but they’re probably not all bad.

What’s so bad about coffee? If you don’t drink too much its not that bad right?

I guess that applies to alcohol as well.

Microplastic is the new asbestos.