Today, I decided to stress-test my LinHT Rev A prototype. The aim was to assess the battery life in the following conditions: minimal transmission time – mostly reception. I used a CC1200 hotspot connected to M17-KCW A as a solid M17 RF source (with stable traffic). The handheld’s backlight (including keypad) was kept on for the whole test duration. Stock Retevis C62 2S Li-ion battery was used, fully charged on the previous day (in the evening). A modified charger was used – I replaced the 0.47ohm resistor with a 0.33ohm one* (a stack of three 1ohm resistors) for increased charge current. Silicon thermal pads were used to allow the SoC to dissipate heat through the aluminum part of the chassis (see this entry for details).
I started the test by switching the volume knob at 9:17 LT. The starting battery voltage was 8.05V.
At 19:17 LT (t+10h), the battery was at 6.7V.
# uptime
19:18:14 up 10:02, 2 users, load average: 0.49, 0.50, 0.47
# ./LinHT-utils/scripts/temp.sh
40.85
CPU slightly below 41 deg. C after 10 hours of continuous DSP work? I think this is a very good result. This would definitely not be possible without some DSP tweaks we introduced in the M17 GNU Radio flowgraph. I had to quickly reset the flowgraph in the first 30 minutes due to an unexpected segfault 🙂 The cause is yet to be found.
Last but not least – big shout out to the rest of our team – Andreas OE3ANC and Vlastimil OK5VAS, and every financial contributor out there. Let’s keep this up 🙂
*the values are taken off the top of my head – I believe they are correct. The idea is to slightly reduce the resistance to increase the current.
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