Arriflex S35 26V power with PRO Rig

[Michael Stumpf]

Hello all,

About to do my first show with the new Arri S35.  It takes 26V power.  Is this a problem with the PRO Sled?  I have my tried and true Gen3 base.  Is the 24V cable that runs through it capable of handling the 26V power that the Arri S35 uses or will it pop the breaker or melt something?  I would prefer not to have to ride a battery on the camera itself and just power the camera/accessories through the sled with the Dionic 26V batteries but clearly don't want to have issues.  As most know GPI is closed on Fridays so asking here.

Thanks.

 

Edited October 14, 2022 by Michael Stumpf

[William Demeritt]

I did a job with the Alexa35, it works fine with 24v power from your sled. The breakers are to prevent overdraw on amps, not volts. I used an old PRO 24v XLR cable (an old Movicam cable I had) into the Anton Bauer gold mount XLR plate, and it powered on from my sled no problem. You can fly 26v batteries in the battery position on the back of the camera, but I wouldn't recommend using 26v batteries on your sled. The 12v pins would become 24v pins, and the 24v pins would then be 48v. No bueno.

[Michael Stumpf]

Oh that's great William, great to know the camera runs on 24V too, thought it needed 26V.

Luckily I still have my old XLR cables too.  I knew my old film cables would come in handy again someday. :)

Thanks

[Jake McClean]

From Arri Alexa35 webpage (see 'Technical Data').
https://www.arri.com/en/camera-systems/cameras/alexa-35

Power Input: 20.5 - 33.6 V DC

Camera will accept any voltage between 20.5v and 33.6v.

The power draw of the camera is listed as 90w, so even if your standard 14v sled batteries (2 combined for 24v mode) drop down to 20.5v, the Max amperage going though your sled is 4.4 amps (more than enough before tripping the 10 amp breaker).
Note: This is just for the camera - not including any accessories you may also be powering.

 

On 10/14/2022 at 8:07 PM, William Demeritt said:

but I wouldn't recommend using 26v batteries on your sled. The 12v pins would become 24v pins, and the 24v pins would then be 48v. No bueno.

Yep - don't do this!



 

[Michael Stumpf]

I'll be prepping this week with the camera.  I'm curious how long the 2x 14V Dionic 90 HC or XT's will run the Arri S35.  Of course the sled will be powering a MDR4 and Light Ranger, as well as a Teradek.  

[William Demeritt]

If I recall correctly, the camera did a solid job running off 2x 90wH batteries for 90 minutes, give or take. I had a similar selection of accessories onboard, so you'll probably do alright.

[Michael Stumpf]

I ended up flying one 26V Dionic on the camera to power it and using the Dionics on the sled just for counter balance and powering the accessories.  Like most digital cameras these days once you put the lens, matte box, light ranger, filters, etc on they are extremely front heavy, especially with the old Panavision Primos we are using on this period piece show.  We don't have a 400' film mag on the back to balance the cameras out, therefore it requires sliding the camera back so far it's nearly off the mounting baseplate itself just to balance it front to back without the (2 lbs) 26V battery on the back, I also mounted my Preston MDR4 on the back to help with the balance.

The question has been, why did Arri feel it necessary to design a wider baseplate for the S35 than every other one of their cameras, requiring an additional adapter plate in order to mount it on a Steadicam or even their own SRH-360 head?