I am concerned about the battery temperature for safety in my office, house, and around my 4-year-old son. :) And I'm curious about logging stuff infinitum.
I have it working with a fixed resistor (without attempting charging yet). On Thu, Sep 6, 2018 at 7:18 AM Graham Haddock <[email protected]> wrote: > Fred: > The temperature coefficient is only important if you are going to use them > as temperature monitors, and you are going to thermally/mechanically attach > them to the battery. > > If you are just trying to get the battery power supply to run, and are not > concerned about battery temperatures, a fixed resistor will work fine. > > --- Graham > > == > > On Thu, Sep 6, 2018 at 3:34 AM Fred Kerr <[email protected]> wrote: > >> I am looking for 10K NTC Thermistors with B=3480. How critical is the B >> value, or what range can I accept? Currently I am looking on Mouser. >> >> Is there a specific or recommended battery pack? I'm just using an 18650 >> from a local surplus store. >> >> Regarding the log file, I still need to do this: >> >> sudo /opt/scripts/tools/developers/update_bootloader.sh >> >> I'll also look for 100K thermistor with B=3960 >> >> On Thursday, August 30, 2018 at 5:35:43 PM UTC-7, Fred Kerr wrote: >>> >>> It runs well with the soldered implementation. My breadboards are a >>> little cheap. >>> >>> The attached minicom_20180830b.cap shows a boot with microUSB power from >>> a wall wart (from my rpi3), then a boot with the battery circuit. I left >>> both RX and TX attached; I'll play with disconnecting them another time. >>> >>> I'll look into getting some "telemetry" info from the pocket beagle. I'm >>> open to suggestions about things to add/log, etc. Also, I think this pocket >>> beagle doesn't have a fix that I got before - after the shutdown, things >>> panic. >>> >>> If anything else jumps out from the log file, please let me know! >>> >>> On Wednesday, August 29, 2018 at 10:59:03 AM UTC-7, Fred Kerr wrote: >>>> >>>> I'll try again soon with my more stable circuit (*soldered), also with >>>> RX disconnected so I just get output from the Pocket Beagle and the only >>>> power input is from the battery circuit. >>>> >>>> (*Soldered, so no loose breadboard connections, better current carrying >>>> capacity, etc.) >>>> >>>> What is a good way to share log files? Mine can get verbose! I could >>>> store it somewhere and post a link - suggestions welcomed! I have a lot of >>>> possibilities, but just let me know what works best for you. >>>> >>>> On Tuesday, August 28, 2018 at 12:51:23 PM UTC-7, Fred Kerr wrote: >>>>> >>>>> Yes, it ran quite a lot longer on the 1F, but still hung. >>>>> >>>>> I wired this up (see pic) to be more stable than the breadboard mess I >>>>> had. The led on 1.8k resistor is gonna run a lot longer than I'll take at >>>>> lunch!!! >>>>> >>>>> Can I isolate RX and TX or...oh I just need TX from the beagle for >>>>> visibility! >>>>> >>>>> 1F 5.5v supercap (that battery was discharged to 3.96v). This one has >>>>> more charge. Also put a 1000uf electrolytic on the soldered version, >>>>> "because". >>>>> >>>>> Fred Kerr (mobile) >>>>> >>>>> On Tue, Aug 28, 2018, 12:13 PM Jason Kridner <[email protected]> >>>>> wrote: >>>>> >>>>>> >>>>>> >>>>>> On Monday, August 27, 2018 at 11:15:36 PM UTC-4, Fred Kerr wrote: >>>>>>> >>>>>>> Hello all, >>>>>>> >>>>>>> I'm being just a little bit careful here: >>>>>>> >>>>>>> I'm about to try this, but I will connect up the serial terminal >>>>>>> first, so I can see output and interact with the board. (Graceful >>>>>>> shutdown!) >>>>>>> >>>>>> >>>>>> Don't connect the power or RX (ie., serial cable to PocketBeagle) >>>>>> signals to avoid them interfering. Great thing to monitor. >>>>>> >>>>>> >>>>>>> >>>>>>> I will test the serial connection first with just a micro USB >>>>>>> charging cable rather than USB to a computer. (Simplify!) >>>>>>> >>>>>> >>>>>> Not sure what you are testing here. Are you just saying you'll power >>>>>> via the microUSB connection and not connect to a computer, just to see >>>>>> the >>>>>> behavior? You are monitoring with a serial connection? >>>>>> >>>>>> >>>>>>> >>>>>>> It's my understanding that LiPo charging is disabled or not present >>>>>>> in the firmware. (I'll give you the "uname -a" and other info the next >>>>>>> time >>>>>>> I fire it up. Just let me know what and how to check.) >>>>>>> >>>>>> >>>>>> It is not enabled by default. There is a flag in the PMIC that needs >>>>>> to be enabled. We've been playing with a driver to set the flag, but >>>>>> there >>>>>> are other bugs in that driver not related to actually charging. >>>>>> >>>>>> >>>>>>> >>>>>>> Also, it's not clear (without reading the data sheet :) ) about the >>>>>>> resistor values for the thermistor and the parallel (linearizing?) >>>>>>> resistor. >>>>>>> >>>>>>> If you have a 10K thermistor, do you put it in parallel with a 10K >>>>>>> resistor, or likewise 100K thermistor in parallel with a 100K resistor? >>>>>>> Do >>>>>>> you put the thermistor anywhere in contact with the (e.g., 18650) LiPo? >>>>>>> >>>>>> >>>>>> Looking at the TPS65217 datasheet says to put a 75kohm resistor in >>>>>> parallel. >>>>>> >>>>>> I'm not sure, but I believe the actual thermal resistor should be >>>>>> something like >>>>>> https://www.ametherm.com/blog/thermistors/thermistors-ntc-thermistor-temperature-sensors-provide-li-ion-battery-safety/ >>>>>> . >>>>>> >>>>>> >>>>>>> >>>>>>> From the prior thread, it seems to be sufficient (if even necessary) >>>>>>> just to connect a 10K resistor from TS (P2-16) to ground (P2-15). >>>>>>> >>>>>> >>>>>> Yes, that is supposed to work, ignoring the battery temperature. >>>>>> >>>>>> >>>>>>> >>>>>>> 10uF cap from battery (P2-14) to ground (P2-15). >>>>>>> >>>>>>> (Tangent/future: What about larger cap, perhaps using a 5.5V >>>>>>> supercap, detect supercap discharging (lipo voltage to ~min input >>>>>>> voltage >>>>>>> on vbat) and give an interrupt to shut the board down?) >>>>>>> >>>>>>> >>>>>>> Thanks in advance for your help, and to the original thread authors! >>>>>>> >>>>>>> >>>>>>> Other posts that I found: >>>>>>> >>>>>>> Safely power down the PocketBeagle supplied by a battery (no >>>>>>> replies?): >>>>>>> https://groups.google.com/d/msg/beagleboard/dDSD89DGzpU/j2WzZyA2CgAJ >>>>>>> >>>>>> >>>>>> I threw in a reply. >>>>>> >>>>>> >>>>>>> >>>>>>> >>>>>>> Supplying two ICs from the PocketBeagle powered by a Lipo battery >>>>>>> https://groups.google.com/d/msg/beagleboard/B7Zyf97hvzY/z8cOt0MHBwAJ >>>>>>> >>>>>>> I want to do some excessive self-telemetry, both internal and >>>>>>> external. I plan to scale the raw battery voltage by 1/11 with an op amp >>>>>>> before feeding to one of the 1.8V ADC inputs. I'll defer to suggestions >>>>>>> about measuring current. >>>>>>> >>>>>>> (This is a tangent: I also plan to be paranoid if I connect to a car >>>>>>> and want to monitor the car's "12V" with something like a VCO on the car >>>>>>> side pulsing to an optoisolator, but I'm sure there are better ideas out >>>>>>> there! :) (I could use several PIC -> nrf24l01 for some "really good" >>>>>>> isolation!) >>>>>>> >>>>>>> Thanks, >>>>>>> Fred Kerr >>>>>>> >>>>>>> On Friday, November 10, 2017 at 10:32:46 AM UTC-8, Adam Saenz wrote: >>>>>>>> >>>>>>>> Keep in mind that the 7V is Absolute Max voltage so you should >>>>>>>> operate below this level or risk damaging the chip. >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> On Thursday, November 9, 2017 at 10:15:05 PM UTC-8, Shannon Mackey >>>>>>>> wrote: >>>>>>>>> >>>>>>>>> >>>>>>>>> I expect I'm overlooking something, But it isn't obvious to me how >>>>>>>>> to power the PocketBeagle with batteries. It doesn't have a similar >>>>>>>>> arrangement to BBB. Can someone point me in the right direction, >>>>>>>>> please? >>>>>>>>> Thanks! >>>>>>>>> >>>>>>>>> -- >>>>>> For more options, visit http://beagleboard.org/discuss >>>>>> --- >>>>>> You received this message because you are subscribed to a topic in >>>>>> the Google Groups "BeagleBoard" group. >>>>>> To unsubscribe from this topic, visit >>>>>> https://groups.google.com/d/topic/beagleboard/PQCNhmeBK3M/unsubscribe >>>>>> . >>>>>> To unsubscribe from this group and all its topics, send an email to >>>>>> [email protected]. >>>>>> To view this discussion on the web visit >>>>>> https://groups.google.com/d/msgid/beagleboard/846799d8-d0bf-481a-9599-cd3b97c1b065%40googlegroups.com >>>>>> <https://groups.google.com/d/msgid/beagleboard/846799d8-d0bf-481a-9599-cd3b97c1b065%40googlegroups.com?utm_medium=email&utm_source=footer> >>>>>> . >>>>>> For more options, visit https://groups.google.com/d/optout. >>>>>> >>>>> -- >> For more options, visit http://beagleboard.org/discuss >> --- >> You received this message because you are subscribed to the Google Groups >> "BeagleBoard" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/beagleboard/84b1f839-cfe2-4dff-b9b3-ecffdc9f2527%40googlegroups.com >> <https://groups.google.com/d/msgid/beagleboard/84b1f839-cfe2-4dff-b9b3-ecffdc9f2527%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> For more options, visit https://groups.google.com/d/optout. >> > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to a topic in the > Google Groups "BeagleBoard" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/beagleboard/PQCNhmeBK3M/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/beagleboard/CANN_KV4icQ5MbPyST%2BSYo_0X9n7_UxudMyCtagT7Oo73qizQ2Q%40mail.gmail.com > <https://groups.google.com/d/msgid/beagleboard/CANN_KV4icQ5MbPyST%2BSYo_0X9n7_UxudMyCtagT7Oo73qizQ2Q%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. 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