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Supercapacitor Power Supply tour

Discussion in 'audio' started by Ciunas Audio, Jan 17, 2019.

  1. Ciunas Audio

    Ciunas Audio Trade: Ciunas Audio

    Btw, is this SDR you are using?
  2. Ciunas Audio

    Ciunas Audio Trade: Ciunas Audio

    In the continuing story of "all you ever wanted to know about supercapacitors but were afraid to ask", here's another snippet

    One other possible advantage to continually energising/charging bank of supercapacitors while using them as power source Vs energising/charging bank of capacitors, then removing charger while they deliver power is something called "deep site charging".

    As Markw already said capacitors (& batteries) are ionic devices storing charge in ions & these ions move through the pores of the electrode. So pores near the surface of the electrode are quickly & easily charged but deeper pores slowly charged up - something like 2000secs is required for these sites to be charged.

    This means that quickly charged supercapacitors have lower energy density than those that are held at charge for a long time.

    The Lithium Ferrous nanoPhosphate (LiFePO4) batteries I mentioned have porosity built into their electrode structure (the nano bit) hence their increased surface area giving lower impedance & I suspect less susceptibility to this phenomena?

    The corollary of this is that the deep site ions would also be released more slowly than shallow site ions - so for instantaneous power may not be so significant?

    This Murata document gives the details on this

    However such model cannot reflect actual electrical behaviors of supercapacitors. This is because that an activated-carbon electrode has various-size pores on the surface. Electric charges are stored by ions moving to the porous electrode surface as mentioned in the section 1.1 (Fig. 2). They can move easily and quickly in shallow site of pores. On the other hand, they move very slowly in deep site due to physical resistance. It means that the shallow site can be fully-charged quickly but the deep site can be charged quite slowly (Fig. 8). For this reason, detailed equivalent model will be described with multiple parallel C and multiple series R as shown in Fig. 8. C and R in the deeper site has high values.​
  3. Aspro

    Aspro Active Member

    Please add me to the 5v list for a Chord Qutest (Aspro)

    5V PS list
    Mort2k (Rob)

    Variable PS (max 20V) list
    Paul Burke[/QUOTE]
  4. Jim Audiomisc

    Jim Audiomisc pfm Member

    In my case, no. Its an ancient radio receiver I'm running at present on some NiCads. It works best at 12V. But the NiCad voltage tends to gradually drop as the cells discharge. This affects performance. Hence I'm considering alternatives.

    I do also use an SDR, but only for RF measurements. It's USB powered. I'm currently thinking of getting an RF sig gen to go with it as I'm getting irritated by the lack of modern checks on VHF/FM stereo tuners. I've started to wonder if any magazine reviewers even have the basic kit for tuner measurements or know how to use it!
  5. Ciunas Audio

    Ciunas Audio Trade: Ciunas Audio

    One characteristic of the LiFePO4 batteries is that they hold their voltage at 3.2V right up to just near depletion when there's a sharp drop off in voltage.

    BTW, related to ions & pores mentioned above for supercapacitors - these batteries use nanoPhosphate structure which increases the surface area (surface pores) of the cathode & hence the low internal impedance. https://www.neces.com/assets/A123-Systems_Nanophosphate-overview-whitepaper_FINAL1.pdf
  6. Ciunas Audio

    Ciunas Audio Trade: Ciunas Audio

    5V PS list
    Mort2k (Rob)

    Other voltages PS list
    Paul Burke (20V)

    I just changed the variable voltage list to "other voltages list" & ask people to nominate the voltage they're interested in
    Thanks Aspro
  7. Aspro

    Aspro Active Member

    According to Rob Watts the Chord DAC designer the Qutest works best with its own switch mode PSU so there's a challenge for your power supply. I'm assuming that you can guarantee that the voltage is 5 volts or as near as damnit! How does the demo/ audition work in practice?
  8. Ciunas Audio

    Ciunas Audio Trade: Ciunas Audio

    Yes, voltage will be 5.1V to accommodate a small voltage drop on the DC power cable. That puts me in mind of a detail I haven't thought of - what DC input sockets do people have on their device to be powered?

    My PS will have a 2.1mm output socket so I'm wondering about cables

    Like the DAC tour, when you receive the package you have a week to evaluate the PS & post it onto the next person in the list whose address I will PM to you. All I ask is that you post your impressions here.
  9. Aspro

    Aspro Active Member

    Voltage sounds fine as does the procedure. Cables/adaptors will be an issue though (input and output). I will need a USB A to 2.1dc(input) and 2.1dc to micro USB(output). I'm happy to source these. They are not expensive but sometimes they end up coming from China so advance notice would be good. Either you ask people what connections they will need and supply them or give them advance notice if they need to source them.

    What is the timing for the initial dispatch to the first person on the list?

    Happy to post my impressions here and also the Qutest thread on Head-fi where Rob Watts is likely to respond so no hiding place!
  10. Ciunas Audio

    Ciunas Audio Trade: Ciunas Audio

    If I understand, your SMPS powers the Qutest via a USB style cable? Is this a fixed cable coming out of the SMPS or removable? The input DC socket on the Qutest is USB type A?

    I will include in the package three DC cables - male 2.1mm to USB type A (short); female 2.1 to USB type A (short) & 2.1mm to 2.1mm cable to extend these. So you should be OK 2.1mm DC to type A will power the Qutest, I think?

    I was due to send out the first 5V PS this week but things got busy - should be next week
  11. 00fiete

    00fiete Active Member

    5V PS list
    Mort2k (Rob)

    Other voltages PS list
    Paul Burke (20V)
    00fiete (12V,3A)
  12. Aspro

    Aspro Active Member

    Qutest is micro USB input but I will source my own cables/adaptors now I know what is supplied.

    Is the quality/output level of the charger an issue?

    What output does the unit provide? I think the Qutest only needs 500 mv.

    How does your unit compare with the Uptone Ultracap? It's cheaper but the introductory price seems to have gone up to 171 €.
  13. Ciunas Audio

    Ciunas Audio Trade: Ciunas Audio


    The quality isn't an issue but the voltage needs to be >7 & <30V. The current output of the charger needs to be greater than the current requirements of what is being powered by the PS. It's easier to deal in watts when considering this - if your device requires 1 amp 5V, that's 5 watts required & your charger should have a greater output than this i.e 9V@ 1Amp is 9 watts

    Up to 3Amp continuous output but far greater than this for instant current demands

    I wrote about the this at the beginning of the thread - biggest difference is that there are no voltage regulators on the supercap PS output - it's current directly from the supercaps which makes a big difference with dynamic current demand.

    Yes, I had to include the 5% Paypal fee in the price but this is refundable if you avoid paypal fees when paying or use Transferwise - unfortunately, I couldn't make this refund automatic in my checkout so I have to refund manually once you let me know you have paid in this way.
  14. Aspro

    Aspro Active Member

    Sorry, I did pick up on the lack of regulation. I was really thinking about type of capacitors used and total capacity. For example I am impressed your PS produces over 3 amps when the Uptone produces 1 amp I think.

    It certainly makes it seems good value and I look forward to trying it. I currently use the SMPS as directed by Chord. I think there must be room for improvement given my previous experience.

    I didn't realise the input voltage could be so variable. I assumed it had to be 5v. Is more powerful better?

    Thanks for the payment clarification.
  15. Ciunas Audio

    Ciunas Audio Trade: Ciunas Audio

    Right butit's not "lack of regulation" - it's where the regulation happens - I use regulation before the supercaps because outputting power direct from supercapacitors (or batteries) makes a significant difference to having a voltage regulator on the output. It's not just about being limited by the power handling of the regulator but rather about the way regulators handle dynamic current delivery.

    As regards capacitors, AFAIK,
    - The Uptone unit uses two banks of 7 10F Nesscap supercapacitors in series to increase the voltage handling capability of each bank to 7 * 2.7V i.e about 19V but this is regulated down to 12V max, I believe @ 1.1Amp max current output

    -The downside of this is that the capacitance is decreased from 10F to 1.4F. More importantly each 10F supercap impedance is 26mohm & 7 * 26 gives 182mohm

    - For 20V PS, I use 8 * 350F Nesscap supercapacitors in series to give a total of 47F & 20V max. The impedance of each 350F supercap is 3.2mOhm so 8 * 3.2 is 25mohm

    - For 5V PS output, I use 2 of these 350F supercaps giving 6.4mOhm

    - the importance of impedance is that the lower the impedance the faster current is delivered.

    One has to bear in mind, however that these low impedances are probably moot as the power has to travel through pcb tracks, wiring & cabling (& usually other voltage regulators) before the power reaches the actual components (In my audio devices I avoid, as much as possible, regulators between power & components). Having said all this, raw supercap power seems to make a difference when powering audio devices which is audible.

    The supercap PS must use a charger voltage rating which is 2V greater than the rated voltage output of the PS. More powerful is better just to ensure that the supercaps are always fully charged when in operation i.e there's no possibility of a sag.

    The other aspect is that when supercaps need to charged up from low charge (initially or when unit is off charge for a week or more), a more powerful PS will ensure the PS comes up to its rated output voltage in less time - we are only talking about 5 mins or so, anyway. The recommended operation is to always keep it on charge.
    Last edited: Jan 27, 2019
  16. Ciunas Audio

    Ciunas Audio Trade: Ciunas Audio

    For all, the user guides are found here
  17. sq225917

    sq225917 situation engineer

    John for plugs you can get dc pins of all sizes with screw terminals, just a simple unscrew to fit and a dab of red marker pen to identify the positive terminal. Saves all that 5.2mm /5.5mm ****ery
  18. Ciunas Audio

    Ciunas Audio Trade: Ciunas Audio

    Thanks, Simon
    You mean a different output connector on the supercap PS?
    A bit concerned about any possibility of wrong polarity or shorting - lots of smoke & destroyed equipment that way.

    The main issue could be the various DC power input connectors on devices being powered - already see the Qutest is micro USB for DC power
  19. sq225917

    sq225917 situation engineer

    Wire it red and black. They're easy to use, but not numpty proof. Not sure how you'd do different usb terminations, though i do have usb A to every other types jacks.
  20. Ciunas Audio

    Ciunas Audio Trade: Ciunas Audio

    Need it to be 100% - can't risk mishaps - anything involving user wiring up is not a runner

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