Slender Posted February 11, 2021 Share #1 Posted February 11, 2021 Advertisement (gone after registration) Hello! I was wondering if any of you ever lusted after the idea of getting, or getting made, a dummy battery for our Leica SL/Q batteries? All other major brands have these possibilities for extending runtime for filming. One can choose to power it from the mains or bigger pro batteries (V-Mount, NPF, Gold mount....) via the correct cabling options available (d-tap, DC barrel...etc.). I know there is a possibiliy to use the USB-C input of the Leica SL2, but one still need to have a charged battery inserted to close the circuit, and depending on the workload/temperature you still are not covered against a risk of drop in charge. And having a dummy battery reduces the heating of the internals a bit, too. Sadly I realise the market demand for videography on the SL2(s) is going to remain too niche for mainstream accessory makers to consider this, but I was wondering if one could still hope to have it custom made (I would be willing to sacrifice the body of an SL2 battery to created a dummy with a P-tap or DC-Barrel 2.5mm cable, honestly). I did powere my camera with a power bank (not a PD one: you can tell when the PD is active with the camera when the "outlet plug" logo is displayed on BOTH rear and top display). 1 Quote Link to post Share on other sites More sharing options...
Advertisement Posted February 11, 2021 Posted February 11, 2021 Hi Slender, Take a look here Battery Eliminator/Dummy Battery Leica SL2. I'm sure you'll find what you were looking for!
beewee Posted February 12, 2021 Share #2 Posted February 12, 2021 I have a little USB-C voltage/current measurement device and it seem when the SL2-S is off and the battery is charging, the USB-C connection only draws 1.45 Amps @ 5v. However, when the SL2-S is powered on, it pulls 0.8 Amps @ 5v which is a bit strange. The USB-C charger supports up to 3 Amps at 5/9/15 volts and 5 Amps at 20 volts (100 watts). Quote Link to post Share on other sites More sharing options...
Slender Posted February 12, 2021 Author Share #3 Posted February 12, 2021 (edited) D 3 hours ago, beewee said: The USB-C charger supports up to 3 Amps at 5/9/15 volts and 5 Amps at 20 volts (100 watts). Thank you for this first clue and answer! Do you notice the "plug" logo on the rear and/or top screen of the camera (next to battery icons) ? I only saw it poping on the top screen once, but I havent tried too many options of cables/charger/PD or not... yet. I did send an email to a chinese company which makes that kind of camera accessories, but it's new year holiday over there at the moment. 😸 There are intermediate solutions between general power banks and all out professional V-mount/D-Tap options such as the power junkie using all too common sony NP-F style batteries. https://www.blindspotgear.com/power-junkie Edited February 12, 2021 by Slender Quote Link to post Share on other sites More sharing options...
Photoworks Posted February 12, 2021 Share #4 Posted February 12, 2021 Yeah, I wonder why Leica does not come out with one, It came be useful . they make one for the S cameras. I stated to make a 3d printed one, but it is not my time priority at this point. There are so many application where it can be useful . 1 Quote Link to post Share on other sites More sharing options...
Slender Posted February 12, 2021 Author Share #5 Posted February 12, 2021 I could very well be your first customer. Quote Link to post Share on other sites More sharing options...
beewee Posted February 13, 2021 Share #6 Posted February 13, 2021 I did another quick test with a different USB-C charger that supports 5/9/12/15/20 volts and the camera still stuck with 5v and charged at the same rate as what I saw earlier. It seems to me that the USB-C connection on the camera doesn’t actually support USB Power Delivery (PD) over USB-C. One other interesting observations is that the battery has 4 contacts with some labels: [+] [T] [D] [-] If I had to guess, the [+] and [-] contacts are probably the positive and negative terminals which supply 8.4v and the [T] and [D] is probably the timing/clock and data lines used for communication between the camera and battery. Given that there are only 2 lines for communication, it’s likely an I2C communication bus. I’m not quite keen enough to probe these lines with a logic analyzer but I’m sure if someone really wanted to do this, it’s not hard to figure out exactly how everything works. Quote Link to post Share on other sites More sharing options...
RoySmith Posted February 13, 2021 Share #7 Posted February 13, 2021 Advertisement (gone after registration) Not all USB-C cables transmit power. Make sure yours is the correct type. Quote Link to post Share on other sites More sharing options...
beewee Posted February 13, 2021 Share #8 Posted February 13, 2021 59 minutes ago, RoySmith said: Not all USB-C cables transmit power. Make sure yours is the correct type. Mine surely does. It charges my laptop at 60 watts. 2 Quote Link to post Share on other sites More sharing options...
beewee Posted February 13, 2021 Share #9 Posted February 13, 2021 (edited) On 2/11/2021 at 9:28 PM, beewee said: I have a little USB-C voltage/current measurement device and it seem when the SL2-S is off and the battery is charging, the USB-C connection only draws 1.45 Amps @ 5v. However, when the SL2-S is powered on, it pulls 0.8 Amps @ 5v which is a bit strange. I repeated the same test with a USB-A to USB-C cable and got the same results. It seems that ~4-5 watt (0.8 amp @ 5v) is the most power the camera can draw when the camera is switched on and ~8.2 watts is the most power the camera can draw while the camera is switched off and charging the battery. Coincidentally, 8.2 watts is just under 1 amp at 8.4 volts which is approximately the voltage that the LiPo battery should be charging at. This is about 0.5C which is par for the course as far as LiPo charging rates go. Edited February 13, 2021 by beewee 1 Quote Link to post Share on other sites More sharing options...
beewee Posted February 14, 2021 Share #10 Posted February 14, 2021 On 2/12/2021 at 8:35 PM, beewee said: I did another quick test with a different USB-C charger that supports 5/9/12/15/20 volts and the camera still stuck with 5v and charged at the same rate as what I saw earlier. It seems to me that the USB-C connection on the camera doesn’t actually support USB Power Delivery (PD) over USB-C. One other interesting observations is that the battery has 4 contacts with some labels: [+] [T] [D] [-] If I had to guess, the [+] and [-] contacts are probably the positive and negative terminals which supply 8.4v and the [T] and [D] is probably the timing/clock and data lines used for communication between the camera and battery. Given that there are only 2 lines for communication, it’s likely an I2C communication bus. I’m not quite keen enough to probe these lines with a logic analyzer but I’m sure if someone really wanted to do this, it’s not hard to figure out exactly how everything works. I noticed that the Panasonic Lumix batteries also used 4 terminal contacts with +|-|T|D. A little more digging around indicates that this is actually a somewhat common/generic circuit for LiPo battery packs. The ‘T’ terminal connects to a thermistor which allows the camera to monitor the battery pack’s internal temperature. Conceivably, for a dummy battery, you can just put a normal resistor in its place. I’m still not quite sure what the ‘D’ terminal is for. 1 Quote Link to post Share on other sites More sharing options...
beewee Posted February 14, 2021 Share #11 Posted February 14, 2021 (edited) Based on this, it seems likely ‘D’ is the data line for a 1-wire data bus. I’m guessing someone would need to reverse engineer the communication protocol to know how to emulate a battery. Edited February 14, 2021 by beewee 1 Quote Link to post Share on other sites More sharing options...
Slender Posted February 15, 2021 Author Share #12 Posted February 15, 2021 (edited) Should we collectively ask Leica in a joint letter? Surely they would jump on the opportunity to rebadge a chinese dummy batterie that can be had for 20 bucks for a meagre 200... It wuold be hard to swallow but at least this will complete their marketing parade about SL2s for video nicely. (like the SCL remote shown in another thread.... shocking). Edited February 15, 2021 by Slender 1 Quote Link to post Share on other sites More sharing options...
beewee Posted February 16, 2021 Share #13 Posted February 16, 2021 Hah! Yeah the problem is that there’s it’s so low volume, I don’t think there’s really a business case for it. Quote Link to post Share on other sites More sharing options...
Photoworks Posted February 16, 2021 Share #14 Posted February 16, 2021 not sure we will ever see a Chinese version. not enough market share. To make one in 3D printing it would cost about $300 1 Quote Link to post Share on other sites More sharing options...
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