On Thursday, September 6, 2018 at 10:22:38 AM UTC-4, Fred Kerr wrote: > > 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). >
Did you ever get your thermistor working and enable charging? > > On Thu, Sep 6, 2018 at 7:18 AM Graham Haddock 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 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 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 >>>>>>> beagleboard+unsubscr...@googlegroups.com. >>>>>>> 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 beagleboard+unsubscr...@googlegroups.com. >>> 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 >> beagleboard+unsubscr...@googlegroups.com. >> 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. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/4a0f639c-ea05-4b5e-92e5-f07fadf535e4%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
