Ian Cooper Posted June 17, 2011 Share Posted June 17, 2011 (edited) HEEEELP!!!! Sorry, I've been a bit busy today - missed your post last night and only just gone online this evening. --> Luckly as you said, both ends have the indication + and - ... --> SO............................................... Is the + WIRE the one connects to the Pin 4? And the - WIRE is the one to pin 0? Read more: http://www.cinematography.com/index.php?#ixzz1PZjDIObL XLR pin 4 is "+" XLR pin 1 is "-" (an XLR connector doesn't have a pin '0') as per the post at the start of this thread... ;) : : Standard wiring for 4-pin XLR connectors is: Pin 1: 0V Pin 4: 12V (which reference to the Tobin website confirms is also the wiring for the TXM22 sync motor) : : Edited June 17, 2011 by Ian Cooper Link to comment Share on other sites More sharing options...
flavio filho Posted June 18, 2011 Share Posted June 18, 2011 Sorry, I've been a bit busy today - missed your post last night and only just gone online this evening. XLR pin 4 is "+" XLR pin 1 is "-" (an XLR connector doesn't have a pin '0') as per the post at the start of this thread... ;) GREAAAAAAAT!!! Sorry to bother you, Iain! That was what I was about to do it... but didn't want to "burn" a Tobin motor, camera, cables,... Imagine that happening... :P Thanks loads again, mate! Really much appreciated. Flavio Link to comment Share on other sites More sharing options...
flavio filho Posted November 7, 2011 Share Posted November 7, 2011 Alright! After a long time here I am again. I've build the cables, much easier than I though. Now I'm going to build/adapt two 12V nicd Battery packs... But I have to have the charger as well. SO... Need help. I saw in other threads people mentioning about the 12V drill batteries (Bosch, Makita), but didn't see how they manage to use them. I believe it can be much cheaper buying some of these or similar alternative (where I could improvise the XLR pins to connect the cable). Anyway, I digress a bit. Am really on it now, so any help would be wicked before I start to "burn" some batteries... :P Thanks, Flavio Link to comment Share on other sites More sharing options...
flavio filho Posted November 7, 2011 Share Posted November 7, 2011 Now I'm going to build/adapt two 12V nicd Battery packs... But I have to have the charger as well. I also need... More technical details of the battery, like MAH, AH, etc... Thanks, Flavio Link to comment Share on other sites More sharing options...
Premium Member John Sprung Posted November 7, 2011 Premium Member Share Posted November 7, 2011 I also need... More technical details of the battery, like MAH, AH, etc... The design rule of thumb for batteries is the "Ten Hour Rate" -- you want to discharge them no faster than that. So, if your camera draws 3.6 Amps, the minimum battery would be 36 Amp-Hours. -- J.S. Link to comment Share on other sites More sharing options...
Ian Cooper Posted November 8, 2011 Share Posted November 8, 2011 The design rule of thumb for batteries is the "Ten Hour Rate" -- you want to discharge them no faster than that. So, if your camera draws 3.6 Amps, the minimum battery would be 36 Amp-Hours. -- J.S. That's certainly the rule of thumb for charging batteries, charge for 13/14 hours at one tenth their Ah capacity (the extra couple of hours is to compensate for losses because the world is less than theoretically ideal). If batteries were only ever discharged at one tenth their Ah capacity then you'd find the minimum length of time anything battery powered lasted would be 10 hours ...torches, electric wheelchairs, portable TVs, cameras, car starter motors, etc. etc, ...the list goes on with the number of portable battery appliances which last significantly shorter periods of time than this. It is perfectly normal to discharge batteries at greater than 1/10 their capacity, however, the simple "Amp.Hour" calculation is not linear at high discharge rates. You probably could draw 1A continuously for 10hours out of a 100Ah battery, but you'll probably find drawing 1A from a 500mAhr battery won't last anywhere near 30 minutes. For example the Ecalir NPR was supplied new with a 4Ah battery, which according to the manual would drive the camera for 4,000ft of film - which would equate to 106 minutes (1:47). I also need... More technical details of the battery, like MAH, AH, etc... Thanks, Flavio As was discussed and shown in your thread concerning making the XLR leads back in the spring, originally the camera was supplied with either a 4Ah or 8Ah battery, with the larger capacity being suited to running the motor & torque motor for long periods of time (2000ft of film quoted). The thread also discussed how the Tobin motor draws less current than the original Arri supplied one, so I suspect if you aim for around 3.5 to 4Ah capacity then that will give you plenty to start with. As recommended on here previously, unless you're recelling an existing battery pack it would be a lot easier to get a 12V sealed lead-acid battery. A quick google shows a 12V 4.5Ah battery available online for £9.63. You'd just need to make a short lead to go from a couple of push on spade connectors to a 4-pin XLR. If you take the battery to a high-street camera shop you'll be able to find a small camera bag it will neatly fit in with a shoulder strap to carry it. The same website advertises basic SLA chargers for about £20. Feel free to make your own 12V NiCad battery pack from tagged cells if you want, but a small sealed lead acid will be a lot quicker, easier and potentially cheaper. Link to comment Share on other sites More sharing options...
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