BMPCC6K power cut out when LP-6 goes flat with ext power

I have literally had my BMPCC6K for less than 24 hours. I installed a fully charged LP-6 battery and connected an NPF-970 as external power using a blind spot, 2TB t5 and recording in 6K BRAW 12:1

After 47 mins, the screen went blank, it stopped recording, then the screen came back on. I pressed record, 5 seconds later it did the same thing. It would always reboot when pressing record. I removed the external power, and clearly the internal LP-6 was flat. I removed the internal battery, then re-connected the external NPF-970 and it records and works fine.

I thought that external power charges the internal battery, and it also seems odd that with the internal one removed, there is plenty of external power to power the camera.

Has any else experienced this or are there any pointers regarding powering this camera reliably?

I have literally had my BMPCC6K for less than 24 hours. I installed a fully charged LP-6 battery and connected an NPF-970 as external power using a blind spot, 2TB t5 and recording in 6K BRAW 12:1

After 47 mins, the screen went blank, it stopped recording, then the screen came back on. I pressed record, 5 seconds later it did the same thing. It would always reboot when pressing record. I removed the external power, and clearly the internal LP-6 was flat. I removed the internal battery, then re-connected the external NPF-970 and it records and works fine.

I thought that external power charges the internal battery, and it also seems odd that with the internal one removed, there is plenty of external power to power the camera.

Has any else experienced this or are there any pointers regarding powering this camera reliably?

You haven't specified the exact LP6 model you were using. The PCC6k draws even more power than the PCC4k and needs a high quality LP6 battery - otherwise you get into troubles.

You haven't specified the exact LP6 model you were using. The PCC6k draws even more power than the PCC4k and needs a high quality LP6 battery - otherwise you get into troubles.

I used the LP-E6 that came with the BMPCC6K. Does the charging function require a higher external voltage (i.e. not just 7.4v), or is the charging only done through USB (which I can't do as I am using the SSD)?

You should use the power supply to charge the battery in the camera.
The internal battery can be charged via USB when the camera is switched off only.

Be careful when using the blind spot adapter.

From the manual p.32:

The voltage requirements of the Pocket Cinema Camera
are as follows:
– The battery input connection is rated from 6.2V to 10V max.
– The DC input is rated from 10.8V to 20V max.
– The camera requires 16W when in standby and is not charging the battery.
– The camera requires 30W when charging its internal battery.
– When powering your camera with a custom made power source, we recommend
removing its internal battery.
– When recording to external media with an active lens, full screen brightness,
full tally brightness, high frame rates and not charging the battery, Pocket
Cinema Camera 6K requires 25W and Pocket Cinema Camera 4K requires 22W.
Pocket Cinema Camera 6K Pro in the same configuration with the addition of
the viewfinder requires 26W.

With the blind spot connected to the DC input you are underpowering the camera because it delivers voltage lower than 10.8V - so it is highly unlikely it will charge the internal battery too.
To me it looks like the camera did first use the internal battery because the external voltage was too low and then couldn't switch over to the NPF970.

The NPF970 itself should be able to power the camera much longer than 47 minutes.

Thank you Robert, I think I missed that lower voltage rating in the manual!

To me it looks like the camera did first use the internal battery because the external voltage was too low and then couldn't switch over to the NPF970.

I agree, but a small mystery as to why it would not work with the flat LP-E6 and external 7.4v NPF, but did work when the flat LP-E6 was removed and only being powered by the NPF. But as you pointed out, if the min voltage is 10.8, then it must be in a condition it can't support.

Be careful when using the blind spot adapter.

Good advice.

I have a dummy LP-E6 which could take the place of the internal battery, powered from the blind spot adapter (7.4v, double checked with a volt meter), then also use the AC power adapter. I have tried this briefly and all seems well, however, as the mains adapter is connected, it is attempting to charge the NPF battery. Not sure whether this will damage the NPF battery or if it will ever get to full charge, but my use case is to have the camera powered externally (mains is fine for what I am planning on doing) but with backup battery power should the mains fail.

Does the charging function require a higher external voltage (i.e. not just 7.4v), or is the charging only done through USB (which I can't do as I am using the SSD)?

Charging the internal LP-E6 through the USB-C port will work only when the camera’s switched off.

I have a dummy LP-E6 which could take the place of the internal battery, powered from the blind spot adapter (7.4v, double checked with a volt meter), then also use the AC power adapter.

I’d refrain from using a dummy battery. Because their specs are rarely standardized, they may cause more issues instead of minimizing them.

The camera’s DC input requires 12 V. If the blind spot only has 7.2/7.4 V DC out, then it’s unsuitable to power the camera.

I’d recommend using an NP-F plate with a 12 V DC out.

Also ensure that the NP-F battery powering the camera is not used to power another peripheral to minimize issues.

Thank you Robert, I think I missed that lower voltage rating in the manual!

To me it looks like the camera did first use the internal battery because the external voltage was too low and then couldn't switch over to the NPF970.

I agree, but a small mystery as to why it would not work with the flat LP-E6 and external 7.4v NPF, but did work when the flat LP-E6 was removed and only being powered by the NPF. But as you pointed out, if the min voltage is 10.8, then it must be in a condition it can't support.

When the camera receives external power and has a non-full battery inside it does try to charge the battery. This would normally draw 30 Watts. On the camera DC input a DC-DC converter tries to convert the voltage to internally stable 12V with up to 95% efficiency (when input voltage is ideal). Efficiency drops considerably when input voltage is lower than designed. That means it could draw well over 36 Watts on your NPF, that's around 5A at 7.4V and surely too much for the NPF battery.

External power is 12V, not 7.2V, unless you want to destroy your camera.
It is not because it works for a while without internal battery that it is within specifications.
The red voltage indicator could be a hint.