It is dishonest by the manufacturer to list these as 12V packs. Their nominal voltage is 11.1VDC.
The Eclair motor needs a bare minimum of 11V to run at accurate speed. Get a 12V NiCd or NiMH pack instead. At least 5Ah. This is assuming your camera is clean and properly maintained. If however your camera is gummed up, it will take a lot more power to advance the film.
Edited by Jean-Louis Seguin, 22 December 2015 - 03:06 PM.
I found Andrew's email. He was replying to questions re my problem getting 75fps. ACLII, latest motor. I'll paste it here, but anyone using these ideas please assume responsibility yourself.
Andrew: We recommend running the motor with a 4Ah or higher capacity battery and a cable no longer than 1.5m. If the camera battery is weak, then with the motor running at 75fps thebattery is discharged rapidly, with the current about 4-5A (depends on the magazine loads). If the cable is too long or has a small gauge, then at 75fps possibly a few volts can be lost on the cable, causing a loss of motor speed. To run the camera at 75fps you have to use a 12V up to 15.6V Nickel Cadmium or Nickel-Metal Hydride battery at least 4Ah strong ; 15.6V battery works better then 12V at speed 75fps, 30% lower current and less heat. The source of your problem with high speeds might be due to the fact that your battery quickly dropped voltage once the current exceeded 4A, as well as the increased current had been generated by friction in the bearings increased by temperature.
The proper current for the 74fps motor just with the camera body (no magazine) with 12V battery is: 24fps - 0.8A 50fps - 1.8A 75fps - 2.7A
Edited by Gregg MacPherson, 28 December 2015 - 06:32 PM.
Oh, don't worry about that. I'm happy that Andrew was able to confirm that the motor can safely take a higher voltage. Your best bet would a 13.2V pack (11 NiMH cells). At full charge without load, it'll be 15.4V, just under the max of 15.6V.
Is the Battery Space pack on that page C size? So it will be heavier than sub-C?
ACL II is already heavy. If the batts are going on board I would be careful about weight. Also, get the weight as far to the rear as you can. I designed, but didn't yet build, a 19mm rod system that allowed handles for hand holding. Instead of using the 19mm rods for box etc, one had handles, and a 15mm LWR system for the rest. The 19mm rods go rearwards, so one can fix a battery well back to improve ballance. When needed, the 19mm base is used for the heavy lens, tripod, big follow focus etc.