Tír Na HiFi

Another well deserved thanks to Tony and crew for an excellent day.

Great to see all the Amps finally stacked after that epic build, the final result still amazes me!
300 Kilograms of pure muscle with 8,400 Amp Hours of Battery power stacked there.

Thanks lads it is no bother I was just delighted to have the two rooms back working and happy to have the feet on terra firma after Thursday's flight home. Great to have them all together after the marathon build. Many thanks again to Nigel for coming up with the idea and his mam for putting up with us for so many weekends over the last is it year and half!

Congratulations on the fine conclusion of the project, Nigel's tower of power pic is the business. Great hosting from Tony of course as usual despite his recent aerodynamics.

Well done lads! It is great to see the project being completed successfully.

Fantastic project and build ;o)
There isn`t a BOM of the components used at the Charge Pcb and Relay Pcb?
If yes, is it possible to buy these prints?
Ask because I would like to use this battery supply to a Krell ksa 100 mk2 clone, there sound fantastic with a lineary psu.

I have a question concerning how you have implemented the regulators. You never drew it out and I am not sure if it is as simple as you make it out to be.

In preparation for receiving one of abraxalito's LING DAC I have decided to place the DAC within an OPPO 103. I am so used to putting on the disk I want with the LP setup I know the SD card player would be better but the question is how much?

I had the 103 around for watching DVDs - had never listened to it as a CD player. I took longer than I thought I would to fix my volume control (moving to an actual box) so I thought I would listen to that to get by.

First impression was that it was much better than I would have ever thought it could be. Not that I am saying it s really good - one could do worse for a short term situation.

I then used one of my chock full of chokes +-15 volts supplies for the analogue and the sound took a big step upward. Not that I have any intention of using the OPPO DAC board.

Looks like it is easy to connect the LING to the 103. There is a ribbon cable from the "transport" side to the DAC board and I just need to get a connector for the LING side to get it running. At least, that is what I am hoping.

I get the feeling the 103 makes for a good transport. So to be sure one has to get rid of the switcher entirely. Of course, I want to use the Keny/nigel battery scheme and now with Nigel's refinement of separate regs for each battery and knowing that trying to charge them in series leads to battery failure I want to use a miniaturized version of the AMP's implementation.

SO, is it just as simple (in my case) of using two 2.5 volts regulators - one attached to each battery? I know when I tried this on LTSpice the voltages did not add so I wonder what I am missing. Looks like you are using the LT1085 with (I assume) a diode in parallel with the input and output. Is there any special way you connect the negative end of one battery with the positive end of the other?

I have a pair of MRAVICA's TPS4070 (I think that is the number) regulators. The one with the pads that allow you to set your voltages. Do you think this would work with your configuration for the LT1085? Nothing against the 1085 it is just that the others are ready to go.

There is a 15 volts output and its ground also on the switcher. This also has a pin labelled "Vcc- Relay" or something like that. With this wire cut everything works just fine BUT if I connect the 15 volts and ground to another supply the player will turn on but it will not recognize the disk.

ANY idea how to get this to work? The only thing I have not tried is connecting this wire to the 5 volts supply.

But the main thing Nigel, is would you be so kind as to assure me how you did the battery thing. PLEASE!

THANKS and take care,

Gentleman, congratulation and a big hand.

It was fun following your project from here, I am sure it will be even more fun to give it a listening. Might take a look at a ferry when winter is gone ;)

Take care
Thomas

Hi Rick
Here are some suggestions:
You can individually charge two batteries in series by using a normal vreg to charge the battery on the ground end of the series & using an isolated DC-DC converter on the other battery in the series - the isolation avoids the input ground of the DC-DC converter being connected to the Pos+ pole of the other Vreg.

I use TDK-Lamda Dc-DC isolators as they are fully regulated in 3.3V, 5V, 12V, etc outputs & come in a variety of power outputs 1.5W, 3W, 6W, etc & also come in various voltage input ranges 5V, 9V, etc.

The model range is CC1R5-, CC3-, CC6- - you'll find them in Mouser - for instance:
https://www.mouser.ie/ProductDetail/TDK ... 2bW4y14%3d

I've never liked the idea of running these LiFePo4 batteries at 2.5V * 2 to get 5V output - it's at the very end of their useful range - so you are not really using the battery as intended!

So here are some ideas:
- Use two supercapacitors @ 2.5V each (use the 2.7V supercaps to give some headroom) & charge each one individually using the scheme above (you can use a cheaper DC-DC converter than the TDK-lambda as your will be using a voltage regulator between DC-DC converter to bring the voltage down to 2.5V. The cheaper DC-DC isolated converters voltage output is not so well regulated as the TDK-lambda ones but that isn't of concern when using a TPS7A4700 to regulate the DC-DC voltage output down to 2.5V. Care has to be taken with this as the discharged supercaps will be seen a dead short to the voltage regulator.

- As above, two supercaps but using a balancing board which limits the voltage on each supercap to 2.5V or 2.7V & charge with 5V across the two supercaps via the balancing board. Care needed with Vreg, as above but you can use a way to gradually ramp up the charging current o avoid stressing the Vreg.

- Use a hybrid battery + supercapacitor: charge the battery to 3.3V & the supercap to 1.7V - again use of DC-DC isolated converter is needed & the same care needed. this way the battery is at it's full charge & supercap is fine at 1.7V - well away from it's 2.7V max range

Lots of variations possible.

Thanks, John, for your counsel.

I agree with you that the 2.5 volts is far from ideal and this was bothering me all the while I was running the batteries down to approx 2.6 volts.

5.2 volts is what the switcher is supplying to the motherboard.

The hybrid idea is intriguing - I don't have any love for the supercapacitor but that does sound worthy of a try. I guess those things are OK if you don't have to put a bunch of them in series to get the voltage tolerance.

THE BIG QUESTION remains: do I simply wire up two assemblies - a 26650 with a 3.3 volts regulator/charger along with a supercaps at approximately approx. 1.9 volts regulator/charger and then put them in series? This is where I get concerned.

I do not see a DC-DC converter at less than 3.3 volts - so i guess one uses this on the 26650 and MRAVICA for the remainder, it can be set to 1.9 volts?

It is really that simple? Will the regulators allow this series connection? Please give me a few details.

So do you enjoy the sound from the supercaps as much as the 26650?

THANKS, again and take care,

rickmcinnis wrote: ↑Mon Nov 05, 2018 9:43 pm..............

THE BIG QUESTION remains: do I simply wire up two assemblies - a 26650 with a 3.3 volts regulator/charger along with a supercaps at approximately approx. 1.9 volts regulator/charger and then put them in series? This is where I get concerned.

I do not see a DC-DC converter at less than 3.3 volts - so i guess one uses this on the 26650 and MRAVICA for the remainder, it can be set to 1.9 volts?

It is really that simple? Will the regulators allow this series connection? Please give me a few details.

Yes, supercap + battery in series - supercap at the gnd end of the series with a 1.9V reg charging it & 3.3V ISOLATED DC-DC converter on the battery. The isolation is the critical characteristic - it blocks the positive voltage on the supercap from connecting to the ground of the charging PS. Because the setup is being powered from one PS, without this isolation you would have a short from pos of supercap to gnd of supercap & fireworks!!

Nige, achieves the same isolation by using a transformer (on each bank of 6 batteries?) with (6?) independent secondaries i.e 6 floating outputs which each charging a battery through Vregs.

So do you enjoy the sound from the supercaps as much as the 26650?

It's a different sound - more bite to it - jury is still out, time will tell.
I'm thinking it's time for a tour of these different PS devices - I have 2 PS products now battery PS & supercap PS - hybrid PS to follow - anyone interested in comparing the sound of these PSes? I should start another thread, not to hijack this one any further.

I would suggest you try 2 supercaps in series as a first test config (it's probably simpler?) & see what you think