<![CDATA[PINE64 - Lithium and RTC Ports]]> https://forum.pine64.org/ Sat, 18 Apr 2026 12:00:03 +0000 MyBB <![CDATA[Powering the A64 LTS from a LiPo]]> https://forum.pine64.org/showthread.php?tid=12420 Sun, 06 Dec 2020 04:51:20 +0000 belsamber]]> https://forum.pine64.org/showthread.php?tid=12420
I have an A64 LTS (2GB) and I am now powering it from a battery pack made of 4 x 18650 cells in parallel. It's also driving a medium sized LCD which is powered by USB, which resulted in some extra complexity in getting enough power to the USB port. 

So, points to note:

1. Battery temp sensor 
The middle wire on the battery connector either has to be connected to a thermistor or to a 10k resistor connected to GND, otherwise the battery will not charge (still powers things fine though)

2. Power jumpers 
There is a pair of jumpers on the board marked DC5V and BAT. According to the schematic, you should jump DC5V if you are powering just from the DC adaptor (default,) jump BAT if you are powering from battery, or have neither connected if you are powering from both. Since I was intending to use this in a portable device (like a laptop) I assumed "both" was correct and had none of the jumpers connected, however this did not give me enough power to the USB. I had to leave BAT jumpered. This seem to work fine - not sure if anyone would care to elaborate on what this actually does. I can see the DC5V jumper connects the DC adaptor to the 5V line, so I assume having it disconnected means that everything is being powered from the AXP803, but I can't figure out what the BAT jumper is doing... If anyone can explain that one to me, it would be great :-)

3. Charging rates with high power USB devices 
Once the battery was discharged, I was struggling with charging it again. It turns out that the Pine and the USB powered screen together were using almost exactly as much power as the AXP803 was putting out when on battery - actually with loaded CPU it was drawing from the battery even with the power adaptor plugged in which isn't great. Thankfully I could adjust the power draw from the DC adaptor using the following path:

/sys/class/power_supply/axp813-ac/input_current_limit

This was set to 1.5A, though according to the data sheet it supports up to 4A. The next higher supported value was 2A (0.5AS increments), which gave me enough headroom to run the device and charge without having to pull from the battery in high load situations. Massive win. The AXP803 does get warmer from pulling more current when the device is both in use and charging, but I have a 3A DC power supply, a well ventilated case and I added a heatsink to the power chip (an old one off an RPI3 set worked perfectly) so to my mind this is moderately safe... If anyone would like to tell me otherwise I'm all ears.

4. Other useful battery tweaks 
The other useful attributes are in:

/sys/class/power_supply/axp20x-battery/

Check the uevent file in that folder to see a summary of what is available - it includes the remaining capacity (percentage) so I'll be using this to drive a "low battery" LED. Notably here you can change the min/max voltage and the max charging current (default is 1.2A, max is 2.8A according to the data sheet, and it's settable in 0.2A increments.) I've kept these at defaults for now, but I may reduce the maximum charging voltage to 4.1V or lower since I have a tendency to use my battery powered devices plugged in a lot, and this slightly lower voltage should increase battery life. Theoretically I could increase the charging current since my battery pack is around 12Ah, but decided to limit the amount of time the AXP803 is working above "typical" values, so stayed with the default on this.

I hope that's a useful summary for someone in future :-)]]>
I have an A64 LTS (2GB) and I am now powering it from a battery pack made of 4 x 18650 cells in parallel. It's also driving a medium sized LCD which is powered by USB, which resulted in some extra complexity in getting enough power to the USB port. 

So, points to note:

1. Battery temp sensor 
The middle wire on the battery connector either has to be connected to a thermistor or to a 10k resistor connected to GND, otherwise the battery will not charge (still powers things fine though)

2. Power jumpers 
There is a pair of jumpers on the board marked DC5V and BAT. According to the schematic, you should jump DC5V if you are powering just from the DC adaptor (default,) jump BAT if you are powering from battery, or have neither connected if you are powering from both. Since I was intending to use this in a portable device (like a laptop) I assumed "both" was correct and had none of the jumpers connected, however this did not give me enough power to the USB. I had to leave BAT jumpered. This seem to work fine - not sure if anyone would care to elaborate on what this actually does. I can see the DC5V jumper connects the DC adaptor to the 5V line, so I assume having it disconnected means that everything is being powered from the AXP803, but I can't figure out what the BAT jumper is doing... If anyone can explain that one to me, it would be great :-)

3. Charging rates with high power USB devices 
Once the battery was discharged, I was struggling with charging it again. It turns out that the Pine and the USB powered screen together were using almost exactly as much power as the AXP803 was putting out when on battery - actually with loaded CPU it was drawing from the battery even with the power adaptor plugged in which isn't great. Thankfully I could adjust the power draw from the DC adaptor using the following path:

/sys/class/power_supply/axp813-ac/input_current_limit

This was set to 1.5A, though according to the data sheet it supports up to 4A. The next higher supported value was 2A (0.5AS increments), which gave me enough headroom to run the device and charge without having to pull from the battery in high load situations. Massive win. The AXP803 does get warmer from pulling more current when the device is both in use and charging, but I have a 3A DC power supply, a well ventilated case and I added a heatsink to the power chip (an old one off an RPI3 set worked perfectly) so to my mind this is moderately safe... If anyone would like to tell me otherwise I'm all ears.

4. Other useful battery tweaks 
The other useful attributes are in:

/sys/class/power_supply/axp20x-battery/

Check the uevent file in that folder to see a summary of what is available - it includes the remaining capacity (percentage) so I'll be using this to drive a "low battery" LED. Notably here you can change the min/max voltage and the max charging current (default is 1.2A, max is 2.8A according to the data sheet, and it's settable in 0.2A increments.) I've kept these at defaults for now, but I may reduce the maximum charging voltage to 4.1V or lower since I have a tendency to use my battery powered devices plugged in a lot, and this slightly lower voltage should increase battery life. Theoretically I could increase the charging current since my battery pack is around 12Ah, but decided to limit the amount of time the AXP803 is working above "typical" values, so stayed with the default on this.

I hope that's a useful summary for someone in future :-)]]> <![CDATA[Lithium battery temperature readout?]]> https://forum.pine64.org/showthread.php?tid=9413 Thu, 12 Mar 2020 06:05:57 +0000 GregH]]> https://forum.pine64.org/showthread.php?tid=9413
I'm running Armbian Buster, and browsing through the data I can see most of what I'd like to see except the battery temperature
Code:
/sys/class/power_supply/axp20x-battery/

Is there a way to read the battery temperature?]]>
I'm running Armbian Buster, and browsing through the data I can see most of what I'd like to see except the battery temperature
Code:
/sys/class/power_supply/axp20x-battery/

Is there a way to read the battery temperature?]]> <![CDATA[Coin cell rapid discharge]]> https://forum.pine64.org/showthread.php?tid=6503 Wed, 05 Sep 2018 18:02:54 +0000 Andrew Armstrong]]> https://forum.pine64.org/showthread.php?tid=6503
For the (probably a minority) who need to use the RTC backup with a coin cell:

The RTC is powered from a 3V supply via a Schottky diode when the Pine64 or Sopine is powered. In theory, a coin cell should be able to back up the RTC when power is off so that a reasonable time reference is available even when there is no network.

Lithium coin cells when new are significantly above 3V, and depending on temperature and newness could be up to 3.3V. This means that if the coin cell is connected via a similar diode, then the RTC will be powered from the coin cell even if the Sopine is fully powered, until the coin cell is partly discharged. 

A possible solution to this would be to increase the supply fed to the diode connected to the RTC pin to 3.3V. 

A solution we are testing for Buffalo Grid, on a custom baseboard for a Sopine, is to use a simple circuit with a P channel MOSFET (connected to conduct in the reverse direction to normal) and a P channel JFET, which is switched off (because it is depletion mode) by the 5V supply connected via a resistor to its gate. When the 5V supply falls below the threshold of the depletion fet, it switches on and that switches on the MOSFET, connecting coin cell to RTC pin.

This only works for cells with a voltage slightly above 3V, because there is still the body diode of the MOSFET which can conduct if there is too large a voltage difference. However this is a junction diode so has a higher forward voltage and lower conduction at low voltages than a Schottky diode. We expect this to make the coin cell last a useful amount longer in its backup role.

It might be a good idea to incorporate a fix for this problem on any new editions of Pine boards.

-Andrew]]>
For the (probably a minority) who need to use the RTC backup with a coin cell:

The RTC is powered from a 3V supply via a Schottky diode when the Pine64 or Sopine is powered. In theory, a coin cell should be able to back up the RTC when power is off so that a reasonable time reference is available even when there is no network.

Lithium coin cells when new are significantly above 3V, and depending on temperature and newness could be up to 3.3V. This means that if the coin cell is connected via a similar diode, then the RTC will be powered from the coin cell even if the Sopine is fully powered, until the coin cell is partly discharged. 

A possible solution to this would be to increase the supply fed to the diode connected to the RTC pin to 3.3V. 

A solution we are testing for Buffalo Grid, on a custom baseboard for a Sopine, is to use a simple circuit with a P channel MOSFET (connected to conduct in the reverse direction to normal) and a P channel JFET, which is switched off (because it is depletion mode) by the 5V supply connected via a resistor to its gate. When the 5V supply falls below the threshold of the depletion fet, it switches on and that switches on the MOSFET, connecting coin cell to RTC pin.

This only works for cells with a voltage slightly above 3V, because there is still the body diode of the MOSFET which can conduct if there is too large a voltage difference. However this is a junction diode so has a higher forward voltage and lower conduction at low voltages than a Schottky diode. We expect this to make the coin cell last a useful amount longer in its backup role.

It might be a good idea to incorporate a fix for this problem on any new editions of Pine boards.

-Andrew]]> <![CDATA[AXP803 BC Detection - D+ and D- Pins]]> https://forum.pine64.org/showthread.php?tid=5424 Tue, 05 Dec 2017 00:56:32 +0000 prkarls]]> https://forum.pine64.org/showthread.php?tid=5424
I'm having issues getting the AXP803 to complete its BC Detection routine. Basically it hangs because the BC_status bit in Register 2C never changes from 1 to 0, indicating the detection is complete.

On the Pine A64, the USB data connections (D+ and D-) are connected to both the AXP803 (DP and DM) and the A64 (USB0). I'm concerned that the connections to the A64 is affecting the BC Detection routine.

Do either the AXP803 or A64 need to be configured a certain way while running this routine? There are a lot of control registers in the AXP803, but the documentation isn't very clear.

Any help would be greatly appreciated.

Thanks,

Phillip]]>
I'm having issues getting the AXP803 to complete its BC Detection routine. Basically it hangs because the BC_status bit in Register 2C never changes from 1 to 0, indicating the detection is complete.

On the Pine A64, the USB data connections (D+ and D-) are connected to both the AXP803 (DP and DM) and the A64 (USB0). I'm concerned that the connections to the A64 is affecting the BC Detection routine.

Do either the AXP803 or A64 need to be configured a certain way while running this routine? There are a lot of control registers in the AXP803, but the documentation isn't very clear.

Any help would be greatly appreciated.

Thanks,

Phillip]]> <![CDATA[Battery level measurement?]]> https://forum.pine64.org/showthread.php?tid=4213 Wed, 08 Mar 2017 18:54:11 +0000 HugoRabson]]> https://forum.pine64.org/showthread.php?tid=4213 <![CDATA[Travelling with the Pine64 (and Lipo battery)]]> https://forum.pine64.org/showthread.php?tid=3413 Wed, 15 Feb 2017 23:29:47 +0000 psychedup]]> https://forum.pine64.org/showthread.php?tid=3413
I've heard that LiPo batteries aren't allowed on air travel in the U.S., but I've also heard that only "spare" batteries are banned. The TSA website didn't clear things up, it just says it's up to the agent at the airport whether it's allowed or not. Who wants to wait until they're at the airport to find out they can't bring something?

So I'm just curious if anyone here has travelled on a commercial flight with your Pine + LiPo battery, and if it was allowed?]]>
I've heard that LiPo batteries aren't allowed on air travel in the U.S., but I've also heard that only "spare" batteries are banned. The TSA website didn't clear things up, it just says it's up to the agent at the airport whether it's allowed or not. Who wants to wait until they're at the airport to find out they can't bring something?

So I'm just curious if anyone here has travelled on a commercial flight with your Pine + LiPo battery, and if it was allowed?]]> <![CDATA[Battery temp pin?]]> https://forum.pine64.org/showthread.php?tid=2938 Tue, 13 Dec 2016 17:25:24 +0000 SvdSinner]]> https://forum.pine64.org/showthread.php?tid=2938 <![CDATA[battery power in android]]> https://forum.pine64.org/showthread.php?tid=1900 Sun, 31 Jul 2016 08:54:02 +0000 UnixOutlaw]]> https://forum.pine64.org/showthread.php?tid=1900
Wifi works - tick
Bluetooth starts - tick
Ethernet works - tick
LCD Panel+touch works - tick
Battery charges - tick
Battery powers pine - UNTICK!

What gives?

I watched its progress charging up an 8000 mAh battery - once charged I pulled the DC in out and it shut off!

Battery definitely connected to the 3 pin PH connector.  Obviously gets a charge through to the battery - why can't I power my pine with the battery?  What's the point in charging it if it won't power the board?  What am I doing wrong?]]>
Wifi works - tick
Bluetooth starts - tick
Ethernet works - tick
LCD Panel+touch works - tick
Battery charges - tick
Battery powers pine - UNTICK!

What gives?

I watched its progress charging up an 8000 mAh battery - once charged I pulled the DC in out and it shut off!

Battery definitely connected to the 3 pin PH connector.  Obviously gets a charge through to the battery - why can't I power my pine with the battery?  What's the point in charging it if it won't power the board?  What am I doing wrong?]]> <![CDATA[CR2032 Battery holder - sanity check]]> https://forum.pine64.org/showthread.php?tid=1824 Fri, 22 Jul 2016 22:30:42 +0000 xalius]]> https://forum.pine64.org/showthread.php?tid=1824
Someone correct me please if I am wrong - but I think the polarity markings inside seem to be off?

After looking at how the contacts are wired, I had to place both coin cells with the negative side up into the holder to get a parallel connection (3V at the connector),
if I put them in as marked, they just seem to short out (measured 1.8V at the terminals....) ?]]>
Someone correct me please if I am wrong - but I think the polarity markings inside seem to be off?

After looking at how the contacts are wired, I had to place both coin cells with the negative side up into the holder to get a parallel connection (3V at the connector),
if I put them in as marked, they just seem to short out (measured 1.8V at the terminals....) ?]]> <![CDATA[Battery Datasheet]]> https://forum.pine64.org/showthread.php?tid=1457 Tue, 21 Jun 2016 01:38:04 +0000 xalius]]> https://forum.pine64.org/showthread.php?tid=1457 <![CDATA[Lithium 'salt and battery]]> https://forum.pine64.org/showthread.php?tid=1211 Mon, 30 May 2016 03:32:32 +0000 UnixOutlaw]]> https://forum.pine64.org/showthread.php?tid=1211
    http://www.ebay.com.au/itm/111706418228

I've only got 2 Pine 64 (2GB), but I can always use another one with NextThing CHIP.

I also ordered 4 of these (thinking it was 1 per package - but turns out I'm getting 40 of them!) :

    http://www.ebay.ca/itm/201477249384

I can always rig them up as adapters to convert between 2 pin and 3 pin connectors...]]>
    http://www.ebay.com.au/itm/111706418228

I've only got 2 Pine 64 (2GB), but I can always use another one with NextThing CHIP.

I also ordered 4 of these (thinking it was 1 per package - but turns out I'm getting 40 of them!) :

    http://www.ebay.ca/itm/201477249384

I can always rig them up as adapters to convert between 2 pin and 3 pin connectors...]]> <![CDATA[Help sourcing LiPo in Canada]]> https://forum.pine64.org/showthread.php?tid=1179 Fri, 27 May 2016 04:34:34 +0000 pinkelephants]]> https://forum.pine64.org/showthread.php?tid=1179
To note, I've also ordered the LCD screen and PlayBox enclosure, with the hope of making a tablet of sorts. Ideal would be a battery that fits into the enclosure, like the 'official' one does. I don't need anything hugely powerful -- even just an hour or two of juice would suit my uses for now.

I do have a battery pack that I can use in a pinch until I find something better, but I'd prefer something that can be charged whenever the Pine is plugged in, plus fits in the case and doesn't take up a USB port.

Thanks for any help!]]>
To note, I've also ordered the LCD screen and PlayBox enclosure, with the hope of making a tablet of sorts. Ideal would be a battery that fits into the enclosure, like the 'official' one does. I don't need anything hugely powerful -- even just an hour or two of juice would suit my uses for now.

I do have a battery pack that I can use in a pinch until I find something better, but I'd prefer something that can be charged whenever the Pine is plugged in, plus fits in the case and doesn't take up a USB port.

Thanks for any help!]]> <![CDATA[RTC Backup Battery - CR]]> https://forum.pine64.org/showthread.php?tid=326 Thu, 18 Feb 2016 14:50:59 +0000 sbentjies]]> https://forum.pine64.org/showthread.php?tid=326 <![CDATA[Minor note about the RTC battery]]> https://forum.pine64.org/showthread.php?tid=308 Wed, 17 Feb 2016 07:31:53 +0000 MichaelMeissner]]> https://forum.pine64.org/showthread.php?tid=308 <![CDATA[Battery + Charging question]]> https://forum.pine64.org/showthread.php?tid=246 Wed, 03 Feb 2016 14:26:13 +0000 adk_mechetech]]> https://forum.pine64.org/showthread.php?tid=246
I wanted to know what the maximum charge current available is.  It's great to have a 5-10Ah battery, but if you can only charge it at 500mA then it's a bit pointless.  I was hoping for at least a 1A charge but preferably a 2-5A charge.]]>
I wanted to know what the maximum charge current available is.  It's great to have a 5-10Ah battery, but if you can only charge it at 500mA then it's a bit pointless.  I was hoping for at least a 1A charge but preferably a 2-5A charge.]]>