Quick Tip: How to get X12 more time than the Sony camera battery

December 4, 2016 by Udi Tirosh 8 Comments

If you are shooting with a Sony camera, you know that they eat and spit batteries faster than I eat M&Ms. One trivial options is carry another set of batteries (though originals are about $45 each). What I am doing is using off the shelf power banks to run the Sony for much longer than its original battery.

Here is the issue. The original sony battery is quite feeble, it carries only 7.3Wh of energy. One issue, is that 7.3Wh is not a lot of energy for video (and definitely small capacity for 4k). The other issue is that this gives you about 5.9Wh per dollar. It’s not horrible, but definitely not optimal.

The Anker power bank that I am using ($45) is 20,000mAh at 4.7V which stores about 94WH of energy, that’s a whopping X12 factor on the sony for the same price.

The only caveat is that you would have to get something to use that cheap energy inside of the Sony. And this is where the Case Relay comes into play. You would need two parts: a Case Relay ($99) and a battery dongle ($35). I am using the sony flavor, but there are dongles for other batteries as well. The combined costs of this bundle is just short of $200. In batteries this is 4.5 Sony batteries. So if you are planning on using more than 4 batteries, this is probably a better solution.

Buying options: Amazon: Case Relay, Dongle, Power Bank | B&H: Case Relay, Dongle.

P.S. the Case Relay as a small internal battery, which means that you can keep the camera on while swapping power banks. If you ever get to that on a 12 battery equivalent pack.

About Udi Tirosh

Udi Tirosh is the Founder and Editor in Chief of DIYPhotography, he is also a photographer, a relentless entrepreneur, a prolific inventor and a dad, not necessarily in that order

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Paul Richardson

The battery is 20,000mAh at 3.7v. the voltage is then stepped up to 5v, and then again to 7.2v by the case relay. 3.7×20000/7.2 =10200mAh
Though you are doing two voltage conversions, and charging a battery.
So you’re going to lose 20-30% on top, which means you only get 7000mAh (ish).

Also the caserelay is expensive for what it is (£100 here in UK). You can build a USB powerbank to camera voltage convertor for about £5-10. Sure it won’t have a battery in, but if you add a y-splitter cable it will allow you to hot swap batteries.

An even better idea is to use high capacity np-f970 batteries. These don’t need to have a voltage conversion, and it runs at about £50 for 2x6800mAh batteries and all.the chargers, adapter plate etc
- udi tirosh
  
  I absolutely hate it that power banks makers use mAh and not WH. mAh is much easier to manipulate. It’s a point for Sony for clearly declaring WH capacity in the specs.
- joe_average
  
  3.7V? usb battery outputs 5V, and 1 dc-dc converter is 80-90% efficient. i’d rather have a usb battery in my bag to charge other gear.
Dim_dim

wow, nice!
cmarker1

Could we just plug the power bank into the micro usb port and recharge the battery in the camera (it would save a good bit of money by not needing the Case Relay and dongle)?
- udi tirosh
  
  At least on my sony A7II, plugging the USB cable moves the camera to charging mode. Sad, but true
  - Kaouthia
    
    I think it varies depending on the camera model and firmware version. Still, even if all Sony cameras could work that way, it doesn’t help Nikon, Canon and other brand shooters that can’t charge their batteries via the camera’s USB port.
joe_average

mAh * V / 1000 = Wh
20,000 mAh * 5 V = 100 Wh
100 Wh / 7.2 V * 1000 = 13,889 mAh
13,889 * 85% = 11,806 mAh @ 7.2 V
low power dc-dc converters are efficicient 80-90% so don’t freak out. using a usb battery is best since 1) they’re cheap and 2) it can charge other gear. even better: get a usb battery with ac outlet or dc output and you could probably skip the $100 case relay (test the dongle output voltage with higher input voltage).