| Electronics > Projects, Designs, and Technical Stuff |
| Good cheap way to get rock solid 12V DC output? |
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| langwadt:
--- Quote from: spec on November 27, 2018, 05:34:48 pm --- --- Quote from: IanB on November 27, 2018, 05:19:55 pm ---One way to define "rock solid" is that the supply should be "stiff", meaning that the voltage remains stable in the event of load fluctuations. One of the stiffest supplies is a battery with low internal impedance. A lead acid accumulator meets this definition, but a high capacity lithium ion battery can also be have a very low impedance. Adding a regulator after the battery may ironically make the situation worse, since a voltage regulator may have poorer regulation in the event of sudden load changes than a battery by itself may have. --- End quote --- Yes, of course, that is why I said to make a standard regulator 'solid'. By the way, batteries can supply big gulps of current, but their voltage is not stable and they are noisy. --- End quote --- noisy and not stable? I'd think a lipo with a reasonable charge will beat most wall warts |
| spec:
--- Quote from: langwadt on November 27, 2018, 05:49:56 pm --- --- Quote from: spec on November 27, 2018, 05:34:48 pm --- --- Quote from: IanB on November 27, 2018, 05:19:55 pm ---One way to define "rock solid" is that the supply should be "stiff", meaning that the voltage remains stable in the event of load fluctuations. One of the stiffest supplies is a battery with low internal impedance. A lead acid accumulator meets this definition, but a high capacity lithium ion battery can also be have a very low impedance. Adding a regulator after the battery may ironically make the situation worse, since a voltage regulator may have poorer regulation in the event of sudden load changes than a battery by itself may have. --- End quote --- Yes, of course, that is why I said to make a standard regulator 'solid'. By the way, batteries can supply big gulps of current, but their voltage is not stable and they are noisy. --- End quote --- noisy and not stable? I'd think a lipo with a reasonable charge will beat most wall warts --- End quote --- :-// |
| Kalvin:
Maybe the solution calls for a solid state power supply. >:D |
| Richard Crowley:
We are all just wasting our time shooting in the dark. @SpannersToSparks has not (can not?, will not?) reveal what his mystery load is. So we can posit guesses forever and never get anywhere. :horse: If that cryptic (and useless) "requirement" is all that the vendor will issue, then I don't see how we can help? |
| spec:
--- Quote from: Kalvin on November 27, 2018, 06:15:45 pm ---Maybe the solution calls for a solid state power supply. >:D --- End quote --- That is correct and what the OP suggested in his opening post. Except he was considering using a switch mode PSU which would require extensive filtering to subdue the switching transients. I am therefore hinting at a linear power supply, say of 10A peak capacity feeding high value electrolytic capacitors to supply the large gulps of current, like a car battery. But also to bypass the electrolytic capacitors with high frequency low ESR capacitors to provide a low impedance and high current capacity across the frequency spectrum. That way you would have better current capacity than a battery, in the sense of this application, with the absolute voltage stabilization of a solid state regulated supply. The techniques for doing this are not difficult. One essential requirement is to use hefty conductors and star point wiring- all pretty standard stuff. |
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