Develop ultra capacitor power supply and LiFePO4 battery power supply

[Daniel Lin]

Originally Posted by iancanada

@Morde

Actually the threshold is 3V. The power supply will be shut down when the output voltage is lower than.

Thank you so much for finding a bug in the user's manual .

Regards,
Ian

Hi Ian,
But my LifePO4PowerSupply turn off when the J2 voltage is about 3.0V~3.1V and J1 is about 3.35V.

After I set "End charge voltage" to higher voltage, let J2 voltage is about 3.4V, and its stable now.

[alazira]

Is it okay to use "A" and "B" versions of the 26650 together?

[MikeyFresh]

I assembled the 26650 cells on this board today and thought everything was fine, after a period of charging I tested the outputs and I am getting zero volts at J4 when there should be 13.2 or so.

The fuse F3 is good, so I'm at a loss to know why I have no juice at J4. Any suggestions on what to check are greatly appreciated, all other outputs measure the correct voltage except for J4.

Thanks very much in advance.

[ofswitched]

Why not use the Prismatic pouch Cell to design a lifepo4 power supply? The pouch Cell has a larger capacity and can be used longer to charge, while the large capacity battery has a lower internal resistance of the pouch cell because the pouch cell does not need to connect more batteries for the large capacity.

[ofswitched]

I think we can buy a LiFePO4 module containing batteries from Taobao and then make a power supply by youself. It can ask for 3.3V or 12V. It has built-in protection and even short-circuit protection which Ian's board doesn't has this fuction. When the LiFePO4 module is low power, you can connect it to the DC of the relative voltage. The battery indicator is also very easy to buy.

Such as photos, such a battery module is only about 21 US dollars.

Those who know a little can also use the relay module to form a more complete charging and discharging architecture.

??12V?????????????YTX14 YTX7A????A123??-???

21310011361380_174.jpg

[yaboin]

Hello Everyone!

I got my board assembled with 10 LiFePO4 cells last night. Much like MikeyFresh I am having voltage issues on J4. All other ports (J1,2,3&5) are functioning as expected.

When I measure the voltage at J4 it is all over the place, not switching quickly, but different between each power on. Values have been from about 6v to 14v.

Measuring voltages on all the cell directly gives me expected values. I can also measure voltage (with the unit in the ON state) from the negative of BT2 to the positive of BT8 and get approx. 13.2v, as desired.

I checked resistance between the different J ports and the batteries directly, all with the unit in the ON state. Of all the links the only one I get a high resistance value is between the negative of BT2 and the negative of J4. I also measured resistance between the pins of the relays from the bottom of the board, both in the On and OFF state. I believe my problem to be the outer most switch of the K4 relay.

With all that said I have two questions:
1. Does that seem like it could be the problem? What else should I check.
2. Any advice on how to replace this, as all the batteries are installed. Would a solder sucker, hot air, etc... be the best option?

thank you in advance.

[LinuxGeek]

Originally Posted by ofswitched

Why not use the Prismatic pouch Cell to design a lifepo4 power supply? The pouch Cell has a larger capacity and can be used longer to charge, while the large capacity battery has a lower internal resistance of the pouch cell because the pouch cell does not need to connect more batteries for the large capacity.

Because the batteries are connected for higher voltage, not for higher capacity. Read the posts before, so you understand what it is meant for...

Originally Posted by ofswitched

I think we can buy a LiFePO4 module containing batteries from Taobao and then make a power supply by youself. It can ask for 3.3V or 12V. It has built-in protection and even short-circuit protection which Ian's board doesn't has this fuction. When the LiFePO4 module is low power, you can connect it to the DC of the relative voltage. The battery indicator is also very easy to buy.

Such as photos, such a battery module is only about 21 US dollars.

Those who know a little can also use the relay module to form a more complete charging and discharging architecture.

??12V?????????????YTX14 YTX7A????A123??-???

Attachment 749226

Who cares ? Ians PSU is not just 4 connected batteries, it features WAY more and ofcourse all the features this batteries offer... What if you stop spamming this thread with taobao stuff, that nobody wants.

[iancanada]

Originally Posted by yaboin

Hello Everyone!

I got my board assembled with 10 LiFePO4 cells last night. Much like MikeyFresh I am having voltage issues on J4. All other ports (J1,2,3&5) are functioning as expected.

When I measure the voltage at J4 it is all over the place, not switching quickly, but different between each power on. Values have been from about 6v to 14v.

Measuring voltages on all the cell directly gives me expected values. I can also measure voltage (with the unit in the ON state) from the negative of BT2 to the positive of BT8 and get approx. 13.2v, as desired.

I checked resistance between the different J ports and the batteries directly, all with the unit in the ON state. Of all the links the only one I get a high resistance value is between the negative of BT2 and the negative of J4. I also measured resistance between the pins of the relays from the bottom of the board, both in the On and OFF state. I believe my problem to be the outer most switch of the K4 relay.

With all that said I have two questions:
1. Does that seem like it could be the problem? What else should I check.
2. Any advice on how to replace this, as all the batteries are installed. Would a solder sucker, hot air, etc... be the best option?

thank you in advance.

@yaboin

Sorry about the issue.

First, please check all of the fuse make sure they are good.

Please also check the polarity of each battery cell. If any was reversed, the protection resistors could be damaged.

Connect a load to J4 with around 50mA current, then measure the Voltage on J4.

Also make sure K1 and K2 is on shortly after the first click sound.

Please let me know if you have more update.

Regards,
Ian

[yaboin]

Ian,

Thank you for the quick response. No worries on the problem, I shorted the pins with my clips while trimming a battery tab. (they got under the tape...) So most likely I am to blame for the problems.

1. The fuses are both good.
2. All batteries verified to be in the correct orientation.
3. K1 and K2 both appear to be on after power up.
4. I forgot to add a led resistor when applying a load and ended up burning up the LED. The unloaded voltage is not consistent from power up to power up, what would be the best way to apply 50 mA load?

In the image below all the resistors circled in blue measure about 0.1 ohms, while the one in red measures 116k ohms. The relay pins circled in blue behave similarly ( Left two shorted in the On state and right two shorted in the OFF state), the three pins circled in red read 100k+ between the middle and left/right in the ON and OFF state. Also all the resistors labeled 2R0 measure 2 ohms.

Imgur: The magic of the Internet

[bigpandahk]

Ian

I am connecting the Buffalo III to your battery supply. What should I do with the onboard Placid regulators? Especially the one for DVCC/AVCC/GND/VD, thanks.