Develop ultra capacitor power supply and LiFePO4 battery power supply

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#425
iancanada said:
@dvb projekt

You can not use the two 3.3V rails for the 6.6V output. So, you can parallel the rest two 6.6V rails together. In this case, 4 cells will be needed.
Click to expand...


That's exactly what I'm looking for too 🙂 Have been following You or at time, and saw the projekt last Year.

If I only need the two 6,6V can I then leave the rest batteryholders empty ?

Is it with an integrated charger og is it bougt seperately ?

What's the price an how do I order ? Do You have an ongoing 2019 buy ?
 
#426
Jorgen E said:
That's exactly what I'm looking for too 🙂 Have been following You or at time, and saw the projekt last Year.

If I only need the two 6,6V can I then leave the rest batteryholders empty ?

Is it with an integrated charger og is it bougt seperately ?

What's the price an how do I order ? Do You have an ongoing 2019 buy ?
Click to expand...

Yes, you can leave the rest of battery footprints empty if you don't need them. But you may need a couple of jumper wires at bottom side of PCB. Programmable battery charger is integrated on the PCB but you will need a external DC power. Standard 18.5V 3.5A laptop adapter would be good to go.

Regards,
Ian
 
#427
Further to my post #399. I tested 3 pcs of 26650 A123 LiFePO4 cells in series.
The cells were brand new then ~95% charged/balanced before the tests. Experience with LiIon cells shows the the performance of the cells can improve after a few cycles.

I measured the output impedance at 44mOhms for the 3 cells, so approx 15mOhm per cell. The transient response is also rather better than the LiIon cells.

Conclusion: Very impressive performance!
 
#428
Dave S said:
Further to my post #399. I tested 3 pcs of 26650 A123 LiFePO4 cells in series.
The cells were brand new then ~95% charged/balanced before the tests. Experience with LiIon cells shows the the performance of the cells can improve after a few cycles.

I measured the output impedance at 44mOhms for the 3 cells, so approx 15mOhm per cell. The transient response is also rather better than the LiIon cells.

Conclusion: Very impressive performance!
Click to expand...


Interesting Dave S, thanks for posting your findings - our ears don't deceive us on this one! Do you have the traces to compare to your other testing...I'm just interested?
 
#430
Hi Crom,

Pic 1: 5mV/div 20uS/div
Pic 2: 10mV/div 2uS/div (close up of load-on waveform)
Pic 3: 5mV/div 2uS/div (close up of load-off waveform)

Battery voltage = 10.24V. Load resistor = 220R. Therefore the load switches between 0 and 45mA at 10KHz and deltaV = 2mV.
So ESR = 2/45 = 44.4mOhms (for 3 cells in series)

LiFePO4.jpg
 
#431
Hi Ian,

I would supply some of your stuff with your new LIFEPO4 battery management board, so I would know what rails I need.

I have to supply:
1 x FIFOII
1 x Dual clock board (without oscillator, external clock)
1 x I2S to PCM converter

Can I supply all 3 boards with a single 3V3 rail? In this case, have I to remove any regulators from the boards?
Or I need 6V6?
 
#432
andrea_mori said:
Hi Ian,

I would supply some of your stuff with your new LIFEPO4 battery management board, so I would know what rails I need.

I have to supply:
1 x FIFOII
1 x Dual clock board (without oscillator, external clock)
1 x I2S to PCM converter

Can I supply all 3 boards with a single 3V3 rail? In this case, have I to remove any regulators from the boards?
Or I need 6V6?
Click to expand...

Hi Ian,

you have P.M.

Andrea
 
#439
My understanding is that Ian had no time to work on the super capacitor supply so there won't be a new one any time soon. That is why he sent out his existing prototype boards out to other people.
Again, this is how I understood his comments, I could be completely wrong.
 
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