It’s easy for sound people to burn through piles of disposable batteries on a typical production day. Wireless microphone systems tend to eat up battery life very quickly, but portable field mixers, portable digital recorders, camera hops and IFB systems all require lots of juice too. There’s an alternative to dumping a bunch of spent batteries into the trash at the end of the day. The solution is to outfit your kit with a battery distribution system, and to utilize capable rechargeable batteries whenever possible.
A battery distribution system powers your entire audio kit with a single rechargeable battery. The basic nuts and bolts of these systems are pretty cut and dry. They require a battery (NP-1 style batteries are often used), a battery cup, a distribution box, and power cables for each piece of equipment. Setting up a system isn’t terribly complex; you just need to make sure you buy the right kind of battery cup for your battery, and the right kind of power cables for the equipment that you use. These systems are simple to operate, and they’ll make your life a lot easier when you’re working.
There’s an environmentally-friendly aspect to eliminating disposable batteries, which is a nice plus, but the real advantage of using a battery distribution system is the improvement it provides to your workflow. Since you’re powering all of your equipment with a single battery, you no longer have to worry about battery life for each individual piece of gear. Never again will you have to stop what you’re doing in order to feed disposable batteries to a faltering mixer, wireless system or recorder. With a distribution system, you pop in a freshly recharged battery at the beginning of a job, power everything up and you’re good to go. If you’re running a lot of gear, it’s a good idea to switch to a second, freshly-charged battery halfway through the day. Other than that, you don’t have to concern yourself at all with battery life. You’re free to concentrate on your work.
Battery distribution systems typically use rechargeable video camera batteries as their power source. NP-1 batteries are really popular because their long and slender bodies slide easily into the bottom of a crowded audio bag, and they pack an impressive amount of power into a relatively small package. A variety of other kinds of video camera batteries can be used as well (Anton Bauer, IDX V-Lock, BP-90, etc.).
The prices for NP-1 batteries can vary, and it's not immediately clear what the difference is between the least and most expensive. There are three kinds of NP-1 batteries available: Nickel-cadmium, Nickel Metal Hydride, and Lithium-Ion (abbreviated as NiCd, NiMH and Li-Ion). Nickel-cadmium batteries are not recommended. Their performance is poor, and cadmium has been proven to be harmful to the environment when not recycled properly. Choosing an NP-1 really comes down to picking between Nickel Metal Hydride and Lithium-Ion.
The average Lithium-Ion NP-1 can power an audio bag with three wireless receivers and a portable mixer for 6 to 7 hours, whereas a Nickel Metal Hydride battery would only provide 4 to 5 hours of use. This is one reason why Lithium-Ion batteries are a little bit more expensive than Nickel Metal Hydride. It's not just extended battery life that makes Lithium-Ion more desirable. Lithium-Ion batteries are also more lightweight, and they perform slightly better in cold temperatures. Lithium-Ion batteries also have no "memory" issues with regard to how much time they need to recharge.
If you decide to put together a battery distribution system, it's a good idea to start out with two batteries and a dual charger. This way you can charge both batteries overnight, and have enough power in the morning to last you for the entire, gruelingly long production day. One option is the IDX NPS-722 Starter Kit, which includes two NP-1 batteries and a charger. VariZoom also offers a nice solution with the KL-5N Battery and Charger Kit (which also includes two NP-1 batteries and a dual charger). Another way to go is to pick up a pair of these Switronix NP-L60 batteries and the SP-2LJ dual charger.
There are a few different companies that manufacture battery distribution boxes. The Remote Audio BDSv4U is one of the most advanced distribution boxes available. It features a USB port for charging and powering equipment (it’s capable of charging a sleeping iPad). The BDSv4U has an exclusive remote port where you can connect an RMv2 Remote Meter or an RS Remote Switch. Both of these compact accessories feature a master on/off switch for the system. This way you can bury your BDSv4U deep in your bag (if need be), and clip the small remote accessory in a more convenient location. The RMv2 also features a display that shows the voltage of the power source and the amperage draw of the connected equipment. If you don’t need the USB option or the remote port, you can opt for the more compact and budget-friendly Remote Audio BDSv4.
Both of the Remote Audio BDS boxes feature six power outlets. One of the power outlets can be switched so that it always supplies power to the connected piece of gear, even ignoring the on/off switch. The power switch at the top of these units illuminates green when the system is on and turns red when power is low. The RMv2 Remote Meter and RS Remote Switch also have this bi-colored LED switch.
Powering either of these Remote Audio BDS boxes with an NP-1 battery requires a BDSNPADW battery cup. If you use a mixer like the Sound Devices MixPre-D, 302, or 552, you will need a BDSCSQN power cable. If you use Sennheiser G2 or G3 wireless receivers, you can power them with a BDS system, but it requires purchasing a Sennheiser DC2 power converter for each receiver, and attaching it to a non-terminated BDSCPT output cable. You can also charge USB equipment with the BDSUSB cable (this can charge an awake iPad). Several more power cables are available in various lengths.
Cable Techniques’ Battery Bud II is an ultra-compact battery distribution box that’s assembled by hand in the United States, and built to survive the rough and tumble realities of location sound. Its design is very audio bag friendly. It has five Hirose power output connectors that all face downward (instead of protruding out to the side), and the power switch is on top, so the user can place equipment on any side of it.
Powering the Battery Bud II with an NP-1 battery requires a Cable Techniques BB-NP cup. If you’re using a Sound Devices 302, 788T or 552, or a Lectrosonics Quadpack, you can power them with a BB-SDMX-12 power cable. You can power two Lectrosonics UCR411A receivers with the BB-BAG-24/2 power cable. Video folks can power an AJA Ki Pro or Ki Pro Mini with
the BB-CSMX-12 power cable. Several more power cables are available in various lengths.
Most basic "off the shelf" rechargeable batteries aren’t good options for wireless transmitters, IFB systems and other power hungry production gear. They tend to behave unpredictably, and generally don’t last long enough to make using them worthwhile. When batteries die in the middle of a shoot, it’s a real burden to swap them out, and entire scenes can be ruined. However, there are a couple of options for rechargeable batteries that work well.
Professional users have reported success using Ansmann 5035442 MAX-E+ 2500mAh rechargeable NiMH AA batteries with wireless transmitters. These batteries can hold a full charge for a number of days after they come out the charger. A single, well-maintained Ansmann 5035442 can reliably power a Lectrosonics SMV transmitter for over four hours of continuous use. If you put the SMV to sleep during breaks using the convenient RM function (with an RM2, RM Remote, or a mobile app), you can get considerably longer run times. Sanyo’s Eneloop 2000 mAh AA rechargeable batteries are also used by professional sound people.
The charger that you use with these rechargeable AA’s is almost as important as the batteries themselves. A quality charger will allow you to “soft charge” and condition your batteries, which gives them an optimal amount of power and is the least destructive (fast charging shortens a battery’s life). This procedure can consume the better part of a day, but it will keep your rechargeable batteries performing at their best. The microprocessor-controlled MH-C808M Ultimate Pro Charger is capable of soft charging and conditioning, and can accommodate rechargeable C and D sized batteries as well.
Sennheiser Evolution wireless systems have remained very popular over the years, however, very few people realize that there’s a rechargeable battery system for them. If you own any Evolution G2 or G3 systems, all you need are a couple of BA 2015G rechargeable battery packs, an L2015G2 recharging station, and an NT20-1-120 AC power adapter, and you may never again have to buy another set of AA batteries for your portable wireless system. With the Sennheiser 100 series, you have to remove the BA 2015G rechargeable battery pack and place it inside of the L2015G2 recharging station in order to charge them.
When it comes to powering wireless transmitters, disposable alkaline batteries can get drained in no time at all. So if you have to use disposable batteries, Lithium AA’s are a better choice because they last much, much longer than alkaline AA’s. At the end of a long production day, you end up with far fewer spent Lithium AA’s to throw away, as compared to alkaline batteries.
There are a number of things that can be done by audio people and other crew members to help conserve energy and cut down on waste: turning off lights during breaks; cutting the ignition on production vehicles that are idling unnecessarily; using fewer disposable water bottles; etc. Getting everyone on set involved in conservation is the key. Group efforts go a long way, but what you do as an individual has an impact as well. Rechargeable power systems aren’t just good for the environment; they can make your life on set better, too.
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