I ran a test using a BlackVue B-130X battery pack that was initially (I explain that in a moment) powering a VIOFO A139 Pro 3CH dash camera in low bitrate parking mode. The battery pack charge level was 19% as reported by the BlackVue battery app within the main BlackVue app.
The estimated amount of remaining time was grossly inaccurate. I started the test run with an estimated run time of 2 hours 2 minutes. The B-130X was able to power the A139 Pro 3CH dash camera for 7 hours 38 minutes (Start Time 12:50 => End Time 20:37). The charge level percentage is also inaccurate especially when it gets to the lower end of the battery pack charge level. (see attached screenshot of the data collected).
At 20:37, I heard the power down chime from the A139 Pro 3CH dash camera. I had just walked out of the room, so I didn't see the exact B-130X output voltage that the VIOFO HK3-C powered off at, but it was around 11.9 volts.
To show how much unused charge there was in the B-130X, I decided to swap out the A139 Pro 3CH for Thinkware U3000 2CH. I didn't want to turn on the charging power to the B-130X to get the U3000 to boot up, so I tied the accessory power wire with the constant battery wire so it would boot. I then disconnected the accessory power wire so the U3000 would go into time-lapse parking mode after the 30 second delay for entering parking mode. The power requirements of the U3000 (0.35 mA) are about 50% of the A139 Pro 3CH (0.70 mA) in parking mode.
The U3000 was able to operate in time-lapse parking mode from 20:45 to 21:31. That would mean the A139 Pro 3CH would likely have run for an additional 23 minutes (roughly). The U3000 test started with a B-130X output voltage level 12.02 volts. When the load of the A139 Pro 3CH was turned off by the HK3-C turning off the power to the A139 Pro 3CH, the B-130X output voltage level rebounded about 0.15 volts. The U3000 2CH was configured that it was connected to an external battery pack, so the low voltage cutoff feature in the U3000 was disabled.
The U3000 2CH time-lapse parking mode test started at 12.02 volts and the B-130X turned off the output power to the dash camera when it reached 10.99 volts. The BlackVue battery app still shows the battery pack charge level of 1% after it turned off the dash camera output power.
If the VIOFO (or any brand) 12/24-to-5V hardwire kits offered a setting to disable the low voltage cutoff feature when connected to a dash camera battery pack, their dash cameras would be able to record for longer periods of time in parking mode.
View attachment 68674
View attachment 68675