Develop ultra capacitor power supply and LiFePO4 battery power supply

I have been using LifePO4 batteries for my FIFO and DAC project for a long time. And also ultra capacitor power supply recently. I'm very happy with their performance and the sound quality.

Both ultra capacitor power supply and LiFePO4 power supply are passive power source. They are totally different to all kinds of regulators which are based on feedback. The most important thing is the perfect load response, much better than any regulator.

Both of them are ideal solution for DAC projects with amazing sound quality. Ulara capacitor power supply is a little bit better but the difference is minor. However the LiFePO4 power supply would be cheaper and easy to integrate into a all in one solution.

I'll work on both for sure. But I'd like to start from LifePO4 power supply.

by Ian, on Flickr



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When power is turned on, all the output rails will be pure LifePo4 battery rail and will be also 100% isolated from each other. I don't want to do anything to degrade the quality of the battery power supply. When it's turned off, all batteries will be charged by a CC-CV charger automatically. The charging progress will be managed and with monitoring.

I've had the same experience as Ian over about the same period of time. I use two cells, one to recharge while the other is in place, so each has about half the use (until one of them, harboring an undisclosed suicide wish, became involved in a brief but spectacular welding incident).

Try one rail for one location as possible as you can. However based on my real experience, one rail for multiple location would still be OK due to the very low internal impedance. Just trust your ears:D.

I do not suggest using and LDO or regulator after LifePO4 or ultra capacitor power supplies, that could degrade the power supply quality.

A lot of people use the small battery manage board for my FIFO project. It's OK, doesn't change the good sound quality, but just feels like a prototype. I'm gonna design a completed all in one solution this time, more closed to finished :D.

Hi Ian. How do you intend to do the switching between the ultracap banks? Relays?

Great projects as always, cannot wait :)


To switch between ultra capacitor banks, relays would have better isolation performance. However, they are a bit noisy, even to switch them every 5 to 10 minutes.

MOSFETs don't have this kind of problem, but they have small leak capacitance around tens of pF. This number could be still reduced by half if to switch both ground and power rail at same time.

MOSFET solution could also be complicated but more flexible.

It's really hard to decide:)