BMPCC4K External/Internal Power Switching Behaviour

Hi! After I happily received a replacement camera for my original BMPCC4K (external power input did not work), I am now doing tests to see how long it runs on various battery setups.

One strange thing I noticed - when simultaneously using Sony L Series batteries via the external power input while having an internal Canon battery as well, the camera actually shuts down after first exhausting the Canon battery, even though it clearly marks "AC" in the battery indicator. Only when I remove the Canon battery can I continue operating the camera via external power (in this case the Sony L batteries last around 3x longer than the Canon ones).

I thought that when the camera uses "AC" power it should ignore the internal battery and ideally even automatically switch power to it once you disconnect the external power source. This is at least the way it should be.

Do you have any experience with this?

I must add that all these tests were done using the Samsung T5 external drive and the Metabones Speedbooster, both of which draw some power.

Does your plate run the Sony battery at 7.2v or regulate it to 12v?

The side power expects 12v so it may be assuming that your Sony battery is dead and instead drawing from the LP-E6. I'd grab a plate that converts the battery to 12v then try.

Hi! Yes exactly, my battery plate regulates the output to 12V. I admit it's on the cheaper side, but I've seen positive reviews when used with the old BMCC, etc.

Next I will try some V-Lock batteries to see if they fare better.

Yeah, if the v locks don't work then I'd get a replacement camera as it's supposed to used the external battery first.