bmpcc 4k Battery problem

Hey folks,

I'm having issues with my blumax np-f970 battery solution.

The way I am using it is so that the battery dc output powers the actual camera, while it's holded by and powering the portkeys L5H5 monitor. You can see this setup on the YT video "MY MINIMALIST BMPCC 6K RIG // FT ZHIYUN WEEBILL S GIMBAL" by James Matthews at 6:25 (sorry, can't post URL's).

This works flawlessly - up to the point, when the battery goes exactly down to 40%. By then it seems like the voltage drops below a certain point, shutting the camera down.

I've made a lot of researches, but couldn't find a proper solution. My father claims, that there are batteries for li-ion, that keep their voltage, but I can't find any np-f970's with the output, that are marked for that.

Do you have any idea, how to fix this? I really want to keep the setup "as is".

Thanks in advance

Just curious but have you compared your batteries’ specs and features with a genuine Sony NP-F970 battery? There might be a clue depending upon the differences if any.

Do you have the camera set to display voltage? That’s the post reliable way to monitor. Once it gets down to 6.4 (I think it will shut off).

Out of curiosity how’s many minutes are you getting before it does?

Concerning the genuine Sony battery doesn't spot any major differences, other than the milage.

Yes, I've been monitoring the voltage. It maybe even get's down a little bit lower than that. When I plugin the battery to charge, they're always at 40% exactly. Can't tell exactly how much minutes I am getting from that.

I've been reading about dummy batteries and been wondering, if these might keep the voltage stable throughout the charge of the complete battery. That would be a solution straight up then of course, but I am not finding any proper information on how they exactly work. Maybe it's just like an "adapter". If anyone has information regarding those, could be handy.

If your feeding power into the DC input socket, in my testing you need at least 10.6 volts for normal camera operation.

Your Blumax F970 only supplies 8.4v in and out according to Amazon. However the camera DC power input requires 10.8v to 20v as per manual p32 below:

Screenshot 2021-04-06 at 22.20.25.png (83.61 KiB) Viewed 771 times

so I'm not surprised it's failing. You might need to use a dummy battery instead of the DC power input as that is rated from 6.2 to 10V as you can see from the manual, so it should work better with your F970.

Someone made this same point in the comments for the James Matthews video you linked to (not sure where his voltage figures came from but the point still stands).

Screenshot 2021-04-06 at 22.30.55.png (60.92 KiB) Viewed 771 times

Concerning the genuine Sony battery doesn't spot any major differences, other than the milage.

Yes, I've been monitoring the voltage. It maybe even get's down a little bit lower than that. When I plugin the battery to charge, they're always at 40% exactly. Can't tell exactly how much minutes I am getting from that.

I've been reading about dummy batteries and been wondering, if these might keep the voltage stable throughout the charge of the complete battery. That would be a solution straight up then of course, but I am not finding any proper information on how they exactly work. Maybe it's just like an "adapter". If anyone has information regarding those, could be handy.

I just tested with a dummy battery. The battery does completely drain. The monitor turned off after about 2.5 hours. Camera carried on until around 3.5 hours. So amazing for £40!

Hello,

thanks for all the answers.

About the dummy battery - that's good to hear it worked and fixes this issue!

Can anyone of you using a dummy battery suggest a proper model? Just in case there might be differences or some not affecting the voltage? Shouldn't be, but just to make sure.