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Battery or Supercapasitor in portable bench power supply?

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tooki:

--- Quote from: Simenhs on December 06, 2022, 05:24:42 pm ---

--- Quote ---If you Google '18650 10A'  or 20A, you will get some hits.  I think LG make a 10A, and Samsung makes a 20A.  And you can use more normal cells in parallel.
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I have ordered some of the samsung ones, will test them when they arrive. The power supply will need to be a bit larger to fit two cells, but not very much, I can fit approximately 1.7 cells :P It seems like cells with lower current rating often have larger capacity rating, so two cells in parallel may give me more than twice the capacity.
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Correct. High-discharge-current cells have lower capacity and reduced cycle life. Highest capacity cells also trade capacity for cycle life. Basically, a less-ambitious cell will have the longest cycle life. 


--- Quote from: Simenhs on December 06, 2022, 05:24:42 pm ---
--- Quote ---What converter are you using for the output of your supply?  Is it boost, buck/boost, or what?
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After the battery, there is a swichmode booster taking the voltage up to 2V more than the output voltage. Then there is a linear regulator taking the voltage back down to the target output. When the output voltage is lover than the battery voltage, only the linear regulator is used. 
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Analog Devices has some linear regulators (like the LT3045-1) that have an output specifically for controlling an upstream switching regulator (by directly controlling its feedback pin), should you want to use an off the shelf part. 

Martinn:

--- Quote from: Simenhs on December 06, 2022, 08:15:20 am ---

--- Quote ---Nice project! How about an 18650 cell in a holder? This way, the battery is replaceable, with spares available anywhere, and with tons of well tested and reputable cells on the market.
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Guess I did a bad job when researching 18650 the first time.
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It would seem so. Check https://lygte-info.dk/info/batteryIndex.html

Simenhs:

--- Quote ---Analog Devices has some linear regulators (like the LT3045-1) that have an output specifically for controlling an upstream switching regulator (by directly controlling its feedback pin), should you want to use an off the shelf part.
--- End quote ---
I did use two lt3080 in an earlier revision. The reason I switched to using a npn and a opamp was firstly that they were completely out of stock, secondly, 2x7$ is a substantial part of the bom cost, thirdly, i could put the output protection diode inside the feedback loop.

 
--- Quote ---It would seem so. Check https://lygte-info.dk/info/batteryIndex.html
--- End quote ---
Thank you so much, that page will be super useful!

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