Hi, I have built a microvawe transformer spotwelder, I have put a single turn of welder wire for in the secondary and I’m timing it with arduino. Worth mentioning it was/is a 230V transformer. Electrodes are sharpened copper rods. I believe the voltage is still high. The spotwelds it produces are slightly discolored and not as...
Pretty basic question but I am struggling to find the words to get the correct search result. The soldering iron I bought came with very narrow tips that I think are supposed to be used for circuit boards and components....
Wattage does not mean how hot it gets, it means how fast it gets to the desired temperature. Also Chinese vendors tend to exaggerate greatly with specifications, especially with cheap products.
I have a 3D printer and have a special filter that has two 24V blower fans that are connected in parallel. Unfortunately my printer doesn’t have the proper connectors for the fans. So if I purchase something like this power jack adapter I know the adapter is 12V not sure if that would make a difference. Anyway if I connect the...
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.
Does anyone recognise these power supplies? They’re cheap AliExpress led drivers and I want to change its output voltage to around 22V from 12V. I’ve read that the way to do this is to adjust the REF voltage on the IC that controls it. It’s a KA3845 but I don’t understand where that reference voltage is regulated. One...
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.
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.
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.
I replaced my laptop’s battery after it was swollen. I found out that services like call2recycle do not take swollen batteries since they are potentially hazardous material. How can I get rid of that damned spicy pillow? In Dallas. Thanks....
Hello, I did manage to kill my cheap-ish bench supply causing it to randomly output up to like 300% the set voltage when under load which did already kill one board. Probably I didn’t actively kill it but the chinesium did its job 🤷🏻♂️. It was a single output supply, when needed I hooked up additional buck- or...
Those wet solder sponges cause a thermal shock every time you wipe the tip. I recommend using brass windings instead. They also won’t completely wipe the solder off the tip either.
You always want a small layer of solder on your tip at all times to prevent it from oxidising. Oxidation means bad heat transfer causing soldering to be much more difficult. Also store it with a small blob of solder on it.
You should avoid scraping or sanding the oxidation of the tip. There is a small layer of silver that won’t oxidise so quickly but below that is normal iron. Not sure if that applied to cheaper Chinese irons but it’s better not to learn bad habits. Once you remove the silver layer you’ll get oxidation much more quickly and you’ll have to keep scraping until the tip is gone.
You can remove oxidation with the brass windings much more easily than with a sponge. When you apply solder with flux the rest of the oxidation should come off fairly quickly.
Buying a cheap model to practice is a great idea, when you are used to that you can look into a better iron. I’ve been very happy with the TS100 but the Pinecil is the newer model apparently.
I just came across this and thought I’d share. I’ve struggled to get headers and IC’s off boards after soldering them on backwards/upside down. This video shows a cool trick with a piece of copper wire that makes them very easy and quick to get off without expensive tooling. I was thoroughly impressed. Hope someone else...
An MPPT solar charge controller using Arduino as well as a homemade Li-Ion battery. Also an 18650 battery tester. So 3 projects simultaneously because they’re closely related.
I’m using a CC CV boost converter to convert solar energy to the voltage for a 7s Li-Ion battery. The arduino reads voltage and current and will try to adjust the CC value to obtain an optimal wattage. I have removed the CC potentiometer and replaced that with an Arduino PWM pin with voltage divider that sets the corresponding current limit. This way a relation between CC pwm duty cycle and solar output can be set.
DIY Li-Ion battery goes hand in hand with the solar project. I’m making a home battery out of salvaged laptop batteries. That requires a battery tester as well which I’m also making myself. The battery tester works by charging a battery with a TP4056 module and discharging as soon as it’s fully charged over a resistor while monitoring voltage/current over time. This happens 16x in parallel using multiplexers so 16 batteries can be tested simultaneously.
I’m also taking safety very seriously so all batteries are equipped with both thermal fuses and current fuses. That involves 3D modelling battery holders, printing them, spot welding/soldering etc. As well as an additional monitoring system on top of a commercial BMS so that the battery status can be monitored remotely. I intend to have a smoke detector, thermostats and an emergency cutoff switch controlled by that second BMS.
Once everything works to a somewhat satisfying degree I intend to post the projects in more detail.
Every project tends to explode in scope in terms of what it all requires so I’m not making as much progress as I want but it has been very educational.
Wanna reuse some old HDDs in the new PC as misc storage and I saw this on a really old drive (the PC it was pulled out of was built in I think 2008/9). Could the discoloration on E9 be because a capacitor leaked? The discoloration seems (from this side at least) to be fully contained on the circle and off of the rest of the PCB
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Microvawe transformer spotwelder. Is there a way to improve it?
Hi, I have built a microvawe transformer spotwelder, I have put a single turn of welder wire for in the secondary and I’m timing it with arduino. Worth mentioning it was/is a 230V transformer. Electrodes are sharpened copper rods. I believe the voltage is still high. The spotwelds it produces are slightly discolored and not as...
What tip should I be using to solder wires together?
Pretty basic question but I am struggling to find the words to get the correct search result. The soldering iron I bought came with very narrow tips that I think are supposed to be used for circuit boards and components....
Is it safe to use a laptop charger to power two parallel 24v fans?
I have a 3D printer and have a special filter that has two 24V blower fans that are connected in parallel. Unfortunately my printer doesn’t have the proper connectors for the fans. So if I purchase something like this power jack adapter I know the adapter is 12V not sure if that would make a difference. Anyway if I connect the...
Adjusting SMPS output voltage (discuss.tchncs.de)
Does anyone recognise these power supplies? They’re cheap AliExpress led drivers and I want to change its output voltage to around 22V from 12V. I’ve read that the way to do this is to adjust the REF voltage on the IC that controls it. It’s a KA3845 but I don’t understand where that reference voltage is regulated. One...
Attempting to repair controller, Have I damaged it beyond repair?
Hey all, have I damaged this xbox 360 controller circuit board beyond repair?...
How to get rid of swollen laptop battery?
I replaced my laptop’s battery after it was swollen. I found out that services like call2recycle do not take swollen batteries since they are potentially hazardous material. How can I get rid of that damned spicy pillow? In Dallas. Thanks....
I need a new bench power supply
Hello, I did manage to kill my cheap-ish bench supply causing it to randomly output up to like 300% the set voltage when under load which did already kill one board. Probably I didn’t actively kill it but the chinesium did its job 🤷🏻♂️. It was a single output supply, when needed I hooked up additional buck- or...
I hate this job (lemmy.world)
Soldering Iron Tips Stop Working/Melting Solder
Hey everyone,...
Neat trick for desoldering many-pin components (youtu.be)
I just came across this and thought I’d share. I’ve struggled to get headers and IC’s off boards after soldering them on backwards/upside down. This video shows a cool trick with a piece of copper wire that makes them very easy and quick to get off without expensive tooling. I was thoroughly impressed. Hope someone else...
What project are you currently working on?
Finally got some free time was thinking about taking up new project but it got me wondering what everyone else is working on? Please share!
Is this a sign of a capacitor leak? (lemmy.world)
Wanna reuse some old HDDs in the new PC as misc storage and I saw this on a really old drive (the PC it was pulled out of was built in I think 2008/9). Could the discoloration on E9 be because a capacitor leaked? The discoloration seems (from this side at least) to be fully contained on the circle and off of the rest of the PCB