One thing that I’ve come across on numerous forums regarding the BMPCC4K are questions about ways to effectively power the camera and get more recording time than what’s available from the standard battery. There are two regular ways to provide power to the camera, apart from using the internal battery option, and the first is by using a dummy battery connected to an external power source and the second is by using the camera’s external power connector to an external power source. It’s the external power source that seems to cause the most issues and raises the most questions regarding what external power source to use, given that many want to power accessories and not just the camera. The power requirements can be quite high if using a field monitor, external SSD, audio recorder and microphone all of which will tax a battery’s capacity.
I’ve experimented with several options and, in doing so, have found some quite viable and inexpensive solutions. The first and most obvious solution is the V-lock battery, not the most inexpensive, but reasonably affordable if you don’t go looking for the high-end brand names. If you’re prepared to shop via eBay (Amazon is pretty woeful for us Australians when it comes to product availability) you can find some very good deals. I’ve already spoken about my Rolux brand V-lock battery and plate that I bought through eBay and it’s proven to be extremely capable, versatile (with many power outlets) and long lasting using the 120Wh battery. So I’d wholeheartedly recommend this setup to anyone that wants a reliable unit that doesn’t cost an arm and a leg. With a battery installed in the camera, you can disconnect the external battery to change it over, such as with the Sony battery adapter that I have or my battery pack option (which I’ll talk about shortly) and keep rolling along.
The V-lock is the traditional external battery option, but there are many instances where this is quite impractical due to its size and attachment requirements, so alternatives are often needed. This is especially the case for those that want to use the camera in its minimal configuration or on a gimbal, where the in-camera battery simply won’t last long enough. Some have resorted to using powerbanks, such as used to charge mobile phones, as these can come with fairly high capacity batteries but ones with connectors other than USB are less prevalent. These powerbanks aren’t always the ideal shape or size either, though some can be quite small, and they also introduce mounting issues when not using a rig. This is where many are looking for other solutions and some manufacturers have come up with their own ideas on how this can be achieved, but one hat doesn’t fit all and, as usual, these alternatives can be quite expensive and still add bulk and weight to the camera.
So one concept I examined was an alternative battery pack, especially as I had one available, and that’s the 18650 battery pack that’s made for LED bicycle lights. These battery packs output around 8.4V and come in capacities that are only limited by the capacity of the installed 18650 batteries. Some of these batteries claim enormous mAh, up to 6800 mAh each, but I highly doubt that these figures are reliable or believable, as brand name 18650 batteries such as from Panasonic or Samsung only come in capacities of between 2500-3400 mAh and often less. My laptop recently died and investigations indicated that it could be a damaged battery pack and, on removal, it showed no voltage so I bought a new pack (which didn’t solve the problem, so it seemed to be a dead motherboard). With nothing to lose, I decided to take apart the battery pack and see if I could make use of the six 18650 batteries. On disassembly, each battery showed a 4V charge, so there was clearly some major damage in other parts of the laptop and perhaps the battery circuit board. The battery pack itself was 41Wh, so quite a reasonable capacity.
Because the batteries seemed to be in good condition, I decided to see how I could put them to use and found that I could get a six-battery holder from eBay that had both a main power outlet as well as a USB outlet. This was perfect for a couple of reasons. Firstly, I could easily connect the battery to the field monitor and reduce the load on the V-lock battery. Secondly, I could use the USB connector on the pack to also power my LS-14 audio recorder, as I couldn’t use the V-lock battery because it was causing severe interference. The six-battery holder could be easily attached to a rig but, more importantly, it served as an example where others could use it to power the camera in a more simple configuration or when on a gimbal. The 41Wh capacity is significantly more than what you get from the standard camera battery that’s rated at only 14Wh, so instead of around 40 min of recording time, you should be able to get around two hours. I say around, because much depends on usage and so some may get more and some may get less, but a nearly 3x increase in capacity is pretty substantial and useful.
The six-battery power pack does a pretty good job and can be fairly easily fitted to my rig and I tried it out on my gimbal to see how that worked out with the attachment method available. It sits sort of OK on the gimbal handle, but as I don’t have a gimbal mountable camera that allows powering while operational (excluding the BMPCC4K) it’s not of much use, though I could use it to power the gimbal and it’s great with my LED lights. As for powering the BMPCC4K with alternative power sources, Blackmagic provided a new firmware update and in the updated manual gives a warning about the use of custom power devices. Unfortunately the manual doesn’t make clear whether this applies to third party battery options such as V-lock batteries and powerbanks, or home made power solutions. It also doesn’t make clear which power sources could impact on the camera’s internal battery.
And as a final word on batteries, after many years of trying out original equipment manufacturer (OEM) batteries and aftermarket batteries, I no longer buy aftermarket batteries for use in-camera. I have had far too many bad experiences with aftermarket batteries to trust any of them inside any camera. The issues aren’t just poor performance, but there is always the risk of one of these batteries swelling and becoming stuck in the camera, or worse. Yes, OEM batteries always cost more than aftermarket batteries, which you can sometimes get a couple for $10 or so, but I’d rather spend the money for something reliable. When you spend significant amounts of money on a camera, I just don’t see the logic in trying to skimp on a battery. For things such as LED lights, field monitors, and even external power sources, I don’t have a problem with aftermarket and use them regularly, but for in-camera, never.