In part 1 I explained some technical background on batteries and powering, as well as providing some suggestions for batteries. In this part we dive into the world of battery distribution systems and mounts.
This is part two of a series of articles, split up as follows:
- Batteries: A Battery is a battery, is a battery
- Battery distribution system (BDS) and mounts
- Cabling and connectors
- Charging and various accessories
Battery/power distribution and mounts
Let’s make some distinction first. A mount is simply a docking station/cradle with a negative print of the offered mounting solution, often with some sort of mechanical or friction locking, so the battery doesn’t fall out.
Usually the mount comes with two leads, so the appropriate connector can be screwed or soldered on, or you buy the mount with the right connector already attached to a cable.
A battery/power distribution system is a fancy pair of words for power splitter. or as we know from our house, the power strip.
like batteries these come in different forms and shapes, with different connectors and options, but in the end they all do about the same. they take the power from the battery and split it out to the different outputs, to provide all your gear the power needed from a single battery. Some BDS even provide a secondary battery input, to allow for hot swapping; when a battery is about to die, you click in a fresh one in the second dock, before removing the first one. So you will have an uninterruptible switch.
Some companies offer a battery cradle and BDS in one solution. This has advantages and disadvantages. in case of failure of one of them, both are ‘toast’, but on the other hand it might be a ‘neater’ solution in the bag.
In the most simple form, a BDS is just a ‘dumb’ splitter. without any fancy things it just splits a power without altering/protecting/monitoring it, just like the white power strip. But some come with more than that. The Remote Audio BDS for example has short-circuit protection, power regulation for some outputs, a 5v USB output and more.
Some technical mumbo jumbo explained:
- Short circuit protection: It’s like the breaker on your power board at home, when both leads are somehow touching each other, the breaker goes off, usually disconnecting and connecting the battery resets this switch.
- Regulated power: Some systems have regulated outputs. Usually the BDS’s for our line of work are set to 12v, a middle ground voltage accepted by basically all field audio recorders. the 5v USB output is also a regulated output.
- Polarity protection: To prevent accidents if one reverses the plus and minus outputs of a battery.
- RF filtering: Few BDS’s have rf filtering implemented. to avoid noise coming in from wireless receivers in the bag.
Regulated power and step up
About all commercially available BDS systems have optional 12v regulated outputs. this to make sure the power provided to the machine is absolute 12v. This can be handy if you have batteries that come ‘very hot’ from the charger. As mentioned in the previous article about batteries, the Zoom F8 for example has a limited acceptance range up to 16v, whilst a charged NP-1 can be a bit less than 17v when fresh from the charger. The downside of this is that the equipment’s build in indicators are not reliable anymore; they always see the regulated/same power/current input, thus this is rendering the fuel gauge on the display useless. Because of that a lot of BDS’s have (optional) displays or simple led guidance (green, orange, red) to give you a realtime readout of the actual battery status. AudioRoot takes that even a step further, and gives you the actual time remaining on the battery. Obviously this will fluctuate when you power on/off extra equipment in the bag.
In the previous article I mentioned that certain batteries have less voltage than the minimum required for our recorders. Like the DV style Sony batteries (NP-F) which provide 7.2/4 volt nominal. So to make that 12 volt minimum, we have to step that up. That can be done several ways. Two common ways to do that are manufactured by Hawk-Woods; With a step up regulator; and by wiring two 7.4v batteries in series. Both have some downsides to keep in mind though. By stepping up some power is getting lost. generally it’s safe to say that most step up converters are about 85% efficient, meaning, if you have a 100 watt/h battery, you will get 85 watt/h after stepping up the voltage. And the downside of a serial connected system is that you always need two batteries connected to the unit. Upside is that the batteries themselves are usually smaller, so that’s why they have a certain place of existence in our world.
Simple solutions and DIY
If you already googled around on the various examples given in this article, you found out that most of these BDS systems are not cheap. As usual they get a fair amount of ‘AV-TAX’ added to the price. Pricing seems even more off if you just want to use one with a simple Talentcell or other non-AV battery solution.
Like how I began this article, a BDS in its most uncomplicated form is just a splitter. Sites like AliExpress, eBay and Banggood offer nice power cable splitters. Often with the wrong connectors for our usage, but we will cover that in the next post, ‘Cables and Connectors’. It’s also not that complicated to make one yourself if you are handy with a soldering iron.
The same sites offer solutions for power regulation. Like this one on Amazon for example, tackling both regulating as well as battery monitoring. Keep in mind that some regulators can cause audible noise in your signal. We will cover that in the last part of our series.
If you need a BDS, most likely you have more equipment to power in the bag and also most likely some of them are not around the 12V input range. For example the Sennheiser G2/3/4 receivers and transmitters are on ~3V. To solve that you have to step down the voltage. Most manufactures sell a separate adapter for that. Like the Sennheiser DC 2 for the previous mentioned G-series, or Lectrosonics’ ISO9VOLT.
If you need 5V USB power for a phone, tablet or other USB powered device, take a look at our tutorial: Tutorial: USB Power for Your Audiobag or Cart
To wrap things up
Again a lot to digest, put hopefully this post demystified some things regarding distribution power in your sound bag. As always, If you have questions or remarks, please put them in the comments and I’m happy to answer them.
This is part two of a series of articles, split up as follows: