DIY Build for Hirose Power Distribution for Location Recording
For someone who has done a fair amount of electronics over the years (especially at Bad Racket Studios) it seemed silly to spend $200 minimum on a commercially available battery distribution box when parts for a power distribution isn’t more than $75 in value. The core function of power distribution is to have a power input that feeds several devices, while protecting against a short circuit or to keep you from drawing to much current. Adding a locking switch prevents accidental power downs while giving you the convenience of being able to power on your whole sound bag with the ease of flipping one switch.
While there are several commercially available battery distribution boxes that offer additional features such as voltage readouts, USB charging, and indicator lights; These are not necessary to the core function of it and could easily be added at a later date. For circuit protection I used an auto resetting circuit breaker, since that’s what all the major brands do. I opted to have mine based around 4 pin Hirose connectors since my NP1 battery cup, Sound Devices 664, and Wisycom Wireless all use Hirose power connections.
Building a Battery Distribution Box
Firstly we need to start with milling the metal enclosure to allow mounting of the switch and 4 pin Hirose connectors. By marking with a sharpie on the aluminum enclosure center points for drilling, then using a prick punch you can get your drill holes to line up perfectly centered. Drill out all the holes to appropriate sizes for the connectors and switch, then lightly round over the jagged edges of the drill holes with a countersink bit. This is also a good time to do the same for the belt clip that allows easy mounting to your sound bag. Once the machining is done, it’s time to prime and paint! I would highly recommend using a high quality spray paint such as Montana Gold Spray Paint, as its base is not only high quality than most other brands I have used but also it is higher pigmented and available in many colors. I did mine in an orange the exact color of my logo for brand coordination.
The next step is wiring the whole thing up. For ease of wiring I like to start by soldering wire pigtails to the appropriate pins on each Hirose power connector. Pin 1 gets the ground, pins 2 &3 are not connected, and pin 4 gets the positive (+) DC power. The input connectors positive lead should get soldered directly to the locking toggle switch, and the output of the switched to the DC auto resetting circuit breaker. All the output connectors’ DC positive (+) leads can be attached to the output of the auto resetting circuit breaker. Additionally the input ground and all output grounds can be tied together.
Once everything has been soldered and the enclosure’s paint has cured you can mount all the Hirose connectors, switch, and belt clip on the enclosure and close up the casing. At this point take a multimeter and test every connection and the switch function to ensure you wired it correctly.
Here you should be able to see a wiring schematic for the Battery Power Distribution box.
Field Testing & Impressions
By this point I have used it out in the field for a number of shoots and it has performed perfectly! The only feature I am missing is USB charging, fortunately building a Hirose to USB charging lead is pretty easy and I will likely do so in the next month. The locking switch is smooth and the locking mechanism easily protects against accidentally power offs. The 6 outputs have been more than enough for anything I’ve encountered thus far. The most I have powered off of it at this time is a Sound Devices 664, Wisycom MCR42S, Lectrosonics SRc, and 2 Lectrosonics 411A, and had no issues what so ever! If you wanna save a few hundred dollars I highly recommend building your own battery distribution box to get power to all your gear in your bag.
Bill of materials
7x Hirose 4 pin Connectors: https://www.mouser.com/search/ProductDetail.aspx?r=798-HR10A-7R-4S73
Die Cast Aluminum Enclosure: https://www.mouser.com/search/ProductDetail.aspx?r=546-1590B
Auto resetting circuit breaker: https://www.mouser.com/search/ProductDetail.aspx?r=457-1610-92-6A
Locking Toggle Switch: https://www.amazon.com/gp/product/B00M1T397Y/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1
Montana Gold High Pigmented Spray Paint: https://www.amazon.com/Montana-Gold-Acrylic-Scampi/dp/B00251AW0A/ref=sr_1_11?s=hi&ie=UTF8&qid=1508803767&sr=1-11&keywords=montana+spray+paint&refinements=p_n_feature_twenty_browse-bin%3A3267894011
Photos of Battery Distribution