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| CR2032 battery voltage with BLE |
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| Rerouter:
looks like your drawing about 0.0332 mA seconds of power per transmission. so apart from Idle consumption, you would have about 270,000 transmissions to use up the rated capacity of most 2032, not correcting for de-rating for your pulse loads, That comes to about 19 hours of battery life at the most providing I have read your time and current sense resistor scaling correctly, |
| jmaja:
As I have said many times the consumption is 27 uAs/transmission. You have measured 33 uAs/transmission, but at least you have clearly too high value for RX/TX, since the picture shows only a bit over 20 mA. With 27 uAs and 220 mAh you get about 3e7 transmissions, which equals to about 2000 hours at 250 ms intervals. The advertising current is about 45 uAs/transmission. Interval is about 5 s. Thus about 11 uA with 1.5 uA deepsleep. After one month or whenever user chooses the device is put to hibernate with <1 uA. In a typical year the device may be advertising 4 months and hibernating the rest. That is a bit under 40 mAh/year + actual usage. If the user is keen to look after the battery, he will put it to hibernate after every use. Then it's just a few mAh + usage per year. Also the user may choose a longer interval and gets more active hours. |
| Rerouter:
ok, yes I mis measured, at least it shows your capacity is countable, 0.027 mAs, so 0.0000075mAh per transmission Yep, don't do math when your tired. :) |
| GeorgeOfTheJungle:
--- Quote from: Rerouter on March 24, 2019, 09:54:55 am ---looks like your drawing about 0.0332 mA seconds of power per transmission. so apart from Idle consumption, you would have about 270,000 transmissions to use up the rated capacity of most 2032, not correcting for de-rating for your pulse loads, That comes to about 19 hours of battery life at the most providing I have read your time and current sense resistor scaling correctly, --- End quote --- 250 mAh = 250*3600 mAs => 250*3600/0.0332 = 27.1e6 transmissions No? |
| jmaja:
I have used Energizer datasheets for comparing CR2032, CR2430 and CR2450, but now I noticed there is something badly wrong in http://data.energizer.com/pdfs/cr2450.pdf. It shows IR to be 100 ohm at just over 300 mAh, but still 9 mA current causes only about 0.2 V difference between idle and load. U=R*I gives 0.9 V. Is there a wrong scale for IR? CR2032 and CR2430 are consistent with U=R*I. Now I also found this one: http://www.dixonelectric.ca/productsheets/energizer/ECR2450BF_3V%20Lithium%20Coin%20Battery_Dixon%20Electric%20ca.pdf It has a completely different curve for CR2450 with the same test setup! Now the pulse curve drops below 2 V already before 300 mAh while in the earlier one that happened at 550 mAh. Almost now additional capacity compared to CR2430 despite of more than double nominal capacity. Renata shows quite different curves for CR2450: https://www.renata.com/fileadmin/downloads/designersguide/DesignersGuide-2011_080813.pdf |
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