06-04-2021, 03:50 AM
(This post was last modified: 06-04-2021, 03:52 AM by dsimic.
Edit Reason: Added a quotation, because of starting a new page
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(05-28-2021, 09:02 AM)megous Wrote: dsimic: I've bought and checked with a better 5A cable. Now the voltage at the Type-C connector is 4.9V at max load, so the max PBP can draw from DC/Type-C VBUS is 11.34W (that's what I measured).
So that's the same as your theoretical 11.4W limit. 
Thank you very much, megous, for the power draw measurement!
The good news is that the BQ24171 works as configured. That bad news is that the total power draw "from the wall" is much lower than what can be provided by the official barrel port charger or a USB PD charger in its default configuration.  They're both capable of providing 15 W.
Slightly OT, but is there also a way to limit the charging to preserve battery-life? Like keeping the battery at 50-70% charge only?
The good news is that it should be possible to tweak the desired maximum battery charge level by adjusting the BQ24171's target battery voltage, which is described on page 16 of the BQ24171 datasheet. However, there are some bad news:
- The target battery voltage is configured using a couple of resistors on the PCB, so those would need to be replaced.
- Reducing the target battery voltage and leaving the maximum battery charging current unchanged would result in further reduction of the maximum power that can be taken from any of the two power inputs, and the battery would even more often be used as the power source for the laptop, even if it's connected to a charger.
- The above-described issue could be mitigated by increasing the maximum battery charging current at the same time, but unfortunately there isn't a lot of room for that. However, there might be a sweet spot.
By the way, after further analysis of the way BQ24171 is used in the PineBook Pro, I'm pretty sure that increasing the maximum battery charging current is the only doable way for increasing the maximum power draw from any of the two power inputs. All components in the power path should be able to handle a 15% to 20% increase of the maximum battery charging current; combined with additional cooling applied to the BQ24171, this should be a win-win hardware modification.
Of course, I still need to re-evaluate the entire approach a few more times, so we definitely stay on the safe side with such a modification.
(06-11-2021, 10:34 AM)dsimic Wrote: The good news is that it should be possible to tweak the desired maximum battery charge level by adjusting the BQ24171's target battery voltage, which is described on page 16 of the BQ24171 datasheet. However, there are some bad news:
- The target battery voltage is configured using a couple of resistors on the PCB, so those would need to be replaced.
- Reducing the target battery voltage and leaving the maximum battery charging current unchanged would result in further reduction of the maximum power that can be taken from any of the two power inputs, and the battery would even more often be used as the power source for the laptop, even if it's connected to a charger.
- The above-described issue could be mitigated by increasing the maximum battery charging current at the same time, but unfortunately there isn't a lot of room for that. However, there might be a sweet spot.
By the way, after further analysis of the way BQ24171 is used in the PineBook Pro, I'm pretty sure that increasing the maximum battery charging current is the only doable way for increasing the maximum power draw from any of the two power inputs. All components in the power path should be able to handle a 15% to 20% increase of the maximum battery charging current; combined with additional cooling applied to the BQ24171, this should be a win-win hardware modification.
Of course, I still need to re-evaluate the entire approach a few more times, so we definitely stay on the safe side with such a modification.
This sounds very promising. I recently purchased the pinebook pro and got the NVME adapter for it. my NVME only uses 3W max and I still have problems with it when the battery gets down to around 20%. Is there a way to increase the amount of power taken from the battery as well?
Gentlemen, it seems on this thread you all may be more familiarized with PBP power circuitry better than I. Something in my PBP related to charging just died, it even made a bird like chirp noise when it did, usb C heated up almost burning.
Any advice on what I should replace? The barrel charger is not working either.
11-21-2022, 03:36 AM
(This post was last modified: 11-21-2022, 03:44 AM by bircoph.)
(11-20-2020, 11:51 AM)xyzzy Wrote: Anyway, a new PCB rev that will draw more than 3A from the DC barrel connector isn't really viable, since it wouldn't be possible to connect any of the existing power adapters without overloading them. It's not possible to just just "draw less" from the 3A adapter. The charger will try to draw more and the adapter will be unable to keep at 5V and drop voltage, or totally lose regulation, or trip a thermal fuse, or (I see the pine supplied adapter is not UL-listed!) catch fire.
It should be possible to use different size of a power plug connector for the revised PBP board. Or just put some red sticker saying min 4A is necessary. If I would have a choise whether to buy old safe power limited board or 4A capable board with all mentioned risks, I would prefer the latter.
(12-04-2020, 11:10 AM)dsimic Wrote: Once the CPU cores are all kept at 100% utilization for an extended period of time (20+ minutes), the heat soak from the SoC affects the battery charging IC (i.e., TI BQ24171), which goes into thermal shutdown. As a result, battery becomes rapidly discharged because the loaded SoC uses a lot of power and there's atually no charging at the same time. Turning the laptop upside-down and providing additional coolling to the back of the laptop turns the previously mentioned 20 minutes into about an hour, but the BQ24171's inevitable thermal shutdown happens anyway.
What will happen if I will remove battery and use bypass cable instead?
Will the board be able to draw at least 15W from standard power supply?
Would it be possible to draw > 15W from different DC adapter that way?
What will happen if power demands (e.g. 100% CPU + NVMe) will be more than what can be taken from a DC adapter?
Will some hardware throttling be in place or just emergency shutdown / hangup will happen?
I want to build some packages on the PBP, not just the kernel, so I'd like to have as much power as possible and ready to remove battery for that case (anyway most of the time my PBP is at home and I can always re-insert battery for travels).
I also want to install NVMe drive, but additional power drain is bloker for now.
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