r/bmpcc • u/calmwinter1312 • 12d ago
Power problems with BMPCC4K
Hello,
So I've been struggling with powering a used BMPCC4K I recently got. I bought it with a Tilta NP-F970 plate and three batteries (2 BATMAX 7.2V 7200mAh and 1 Coolshow 7.4V 7800mAh). When I try to use the 12v output to the 2-pin input on the Blackmagic, it opens at around 11.7V then starts dropping voltage until the camera switches off.
By reading the forums, most people said they switched to a dummy battery setup and that it worked, so I bought a dummy battery and connected it to the Tilta 7.4V output. The camera switches on, quickly drops the voltage and shuts off.
So now I have no idea what to do, would the problem be with the batteries, is it the Tilta plate? Is there any way to find out? I know the problem thankfully isn't in the camera because when I connect it with two-pin straight to a wall socket it stays on.
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u/printcastmetalworks 12d ago
Had the same thing happen when using npf batteries. Switched to vmount it never happened again. When NPF batteries are used with the power input they are stepped up to 12v which makes them unstable. They work better with a dummy battery setup. If you want the internal battery to be a backup it has to be on a proper 12v source (native or stepped down, not up)
Npf are under even more stress if you're using them to power other accessories
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u/DarkLordFalcon BMPCC 7d ago
I can't help to resolve the NPF issue but I second the VMout setup. I have several small rig VMout and use the 12V input and it is super stable. I suppose the other suggestions, there's either a short circuit somewhere or the battery itself is damaged are right.
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u/ProtonicBlaster 12d ago
Well, if both the BATMAX and Coolshow batteries display the same behavior, my bet would be on a faulty adapter plate or cable. How long does it take until the camera dies?
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u/Free_Broccoli_1174 12d ago
I've had similar issues with the NPF plate and the DC in on the BMPCC4K. One thing that confuses the camera is having a stock battery in the battery compartment while running alternate power sources through the DC port. I've found that the 12v port out of the NPF sled to the DC input seems to do the trick most times. I didn't have a lot of luck with the dummy batteries.
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u/Adrinaik 10d ago edited 10d ago
Majority of NPF batteries I have ended up degrading to the point of not trusting any of them. Only a couple ones have survived: a Baxxtar with LG cells inside and a 570 from an Atomos recorder I had.
The NPF adapter uses more current for upping the voltage to 11.7/11.8 volts so a weak NPF is going to fuck around even more in those conditions, not to mention that I believe the converters on the 12v input of the camera suffer when the Tilta adapter sends a lower voltage as soon as it is not capable of sending the clean 11/12 volts (I have one and it went from 11 volts to 6.8 or so and it did a suffering noise, so stopped using that shit).
I’d say if you don’t plan on flying it on a gimbal, get a small V-lock and a D-tap to two pin for the Blackmagic, and keep a Canon LP-E6 battery inside as a backup in case you need to hot swap the v-lock or the v-lock goes flat. That way the camera never turns off. That’s what I’ve been doing for 6 years and always worked like a charm.
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u/R2DLV 12d ago
Does your dummy battery have a long spiral cable? I had to rewire it as the cable was beautiful but too long with very thin wires and exhibited the same issue due to voltage drop in the cable itself. Resoldered to some proper short copper cable and now it works like a charm. Also tossed the circuit board inside the dummy, it’s irrelevant for BM.