I'm researching how to prevent data corruption from SD card and I found this option to use the super capacitor in the power line.
But I also found this quote about leaking, so I researched a model I found at the local store, and the seller didn't know what the capacitor's working voltage was.
I looked for the image and found that this model can operate from -25°C to 70°C, I believe it might be interesting to check the working temperature well, as most low cost PTH capacitors are 85°C. It is also interesting to observe the recommended discharge current ("200uA or less"? "3mA or less"?).
My question would be what issue or problem are you having that you are trying fix ?
For a Supacap you need to measure the current you circuit takes and the work out what size capacitor is needed to provide that current for the time you want at the voltage you want .
No too simple . I point my finger in the air and it says you are looking at a big cap - 10,000micra farad ? ( and you will need to limit the current when you charge it up )
You could use a dry battery feeding the circuitry via a diode , so it takes over when power fails , or even a rechargeable lead acid battery .
But … respond to the first paragraph first ! ( X/Y)
In my case the problem is space, and also temperature. It is a switched power supply, the components take up a lot of internal space and due to the power being 750W it heats up well, has forced ventilation, but I believe that using a battery there is not very recommendable. I'm thinking of using a W25Q64 instead of the SD card, and don't use backup power supply, probably data loss must occur at some point. I want to collect data for a possible intermittent issue. The user claims power supply failure during use, but when testing on the bench, no defect occurs. As the operation of the power supply depends on external control, I believe that data collection can help to find this possible failure that may be occurring, whether internally or externally. The equipment that uses the power supply does not accompany the power supply when it is sent for maintenance, so it is difficult to evaluate.
About the choice of capacitor, yes, it really is a bit complex, here is a post from a manufacturer:
A supercap is not the solution. Instead, use 100 nF decoupling caps to GND, as close to power pins as possible, and 10-100 uF across power and GND further away. For extreme cases, an RC decoupling filter may be needed.
Better: determine the source of electrical noise on the power leads and fix that.
The general search terms are "power supply decoupling methods".
What is using 750w ? Why not mount the Arduino bits somewhere else ( cooler ). Anything running at 70C will have reduced reliabilty ( and regulators etc trying to dissipate power will over heat ). The power supply shouldn’t be that hot ( as it’s a switch type) and may not be suitable for its task
( too small? Overheating and cutting out ?)
I would look at fixing this and why you are getting power supply failing . I’m not sure logging it whilst using it as the power supply will work that well.
