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CP-16 Battery/ AC adapter Project


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#1 Matthew W. Phillips

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Posted 08 May 2014 - 01:18 PM

I had mentioned previously about how my camera test footage came back crap due to smeared footage and light leak. I, in true impulsive and short tempered fashion, was ready to sell my gear and go digital. I listed the parts on eBay BEFORE talking to Paul Hilman like I should have.

 

The next day I got an email back telling me to call Paul. I called him and he is a wonderful man. He walked me through how I could fix the problems myself and how to save money doing so. Suffice to say, i am pretty much sure that the camera problems are fixed. 

 

Problem is, before I found this out, I had already sold my "dummy block" AC adapter for $150. I cannot find these things anywhere and I don't want to pay that much anyway so here is the birth of my current project of which I would love input and advice.

 

In 2013 when I owned my other CP16, I only had batteries and a charger. I always wanted an indoor supply that didn't need to be charged because so much of what I shoot is interiors anyway. I had messed around with some mad scientist creations that involved alligator clips, etc, and I made a setup that could theoretically run the camera at the right voltage (20V) and supply more than enough current (3A) using a laptop  power supply to a DC port that was soldered to two wires that connected to alligator clips to attach to the power pins on the side of the camera body. This wasnt meant to actually be usable on set but just to see if it works. It did and it kept sync (at least according to the fact that the sync light never came on)

 

Now, I am reviving that idea but I have a more realistic way of how this can be used.

 

I purchased this $3.99 case from Radio Shack.

cp_proj01.jpg

 

And I found the power pins distance by pushing hard against them with the case. It made two slight indentations that I could use to hole punch on and then drill. I used a 7/64 bit.

cp_proj02.JPG

 

Sliding this into the battery part worked beautifully as it clicks into place and doesnt move. The enclosure is slightly undersized at 2" wide and 1" deep compared to 2 1/8" wide and 1 1/4" deep. However, the tightness of the power pins into the 7/64 holes makes for a nice and tight fit that will not come lose without a decent amount of effort.

cp_proj03.JPG

 

My main point of this post is as follows:

 

1) Once I add a DC port to the other end of the case, what would be the best (cost as well as stability) way to connect the DC port wires to the hole where the pins will make contact?

 

2) Is there anyway where this same idea can be applied to make renewed battery packs so that people don't have to painstakingly track down old CP batteries, try to open them, and risk cracking them or dealing with old internal batteries?

 

3) Is there any flaw in my plan as far as attaching 20V laptop batteries (like a universal per se) to the DIY dummy block that I am not forseeing?

 

Thanks.


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#2 Zac Fettig

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Posted 09 May 2014 - 07:10 AM

1) Solder them to a fixed block of metal, then pot them (hot glue will work in a pinch, or electrical tape). You should be able to get 7/64" brass rod fairly cheap.

From McMaster: http://www.mcmaster....859k342/=rw0r2g

 

2) Not a bad idea at all. I've done the same with Scoopic batteries. Went to 3d print a battery shell and it was nearly $60!

 

3) The only flaw you'll run into is that the camera will deep draw off the battery: It will pull more current for a short period of time, as opposed to a laptop which will pull a little bit over much longer period of time. Modern batteries (NiMH or Li-ion) tend not to like this very much. You should be fine if you use more batteries in parallel or, switch to a battery meant to be deep drawn. Power tool (cordless drill, etc.) batteries would be a good choice. They're cheap, commonly available, chargers are easily available. Etc. I use external camera flash batteries (Gel Lead Acid) to power my Arri.

 

Hope this helps!


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#3 Matthew W. Phillips

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Posted 09 May 2014 - 10:06 AM

Is it safe to have metal directly contacting the inside of the ABS plastic in the box or does it have to be insulated? I only ask because my current design uses 1/2" aluminum spacers with a threading of 6-32 to mount the "female leads" to the camera body pins. The inside of the case is attached to the spacers using a 6-32 screw on the other end with a wire connector sandwiched between. the wire connector of course connects to the wire which attaches to the DC jack on the other side of the case.

 

Is this safe or will the ABS plastic melt by having a metal screw mounted to the case chassis?


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#4 Zac Fettig

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Posted 09 May 2014 - 02:00 PM

It really depends on how much current is flowing through the leads, and how small they are. If they have a thick enough cross section that they're not burning up, you should be fine. The #6-32 screw should be .138" THK [major diameter], so ~400 amps continuous before it would fuse (assuming copper/brass screws).

 

Since you can run it off batteries, I'm guessing it's in the 1-10 amp range though. And I doubt it'll warm up at all for those kinds of currents. ABS hits glass transition around ~170 F, so you should be safe there too.

 

It should be safe. The ABS is an insulator, so no worries there.

 

http://en.wikipedia....ican_wire_gauge


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#5 Matthew W. Phillips

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Posted 09 May 2014 - 03:13 PM

Thank Zac. I appreciate all the input. I'll post pics of my product when it is finished.


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#6 Matthew W. Phillips

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Posted 11 May 2014 - 04:30 PM

For anyone who is interested, I have completed the DIY CP-16R AC adapter exclusive! I fired it up and it works like a charm! And what is even cooler is that it is all new parts and I don't have to rely on something built before I was born. 

 

Here is a picture of it in the camera.

 

100_2422.JPG

 

It still wasn't cheap but much cheaper than paying $325 for one from Whitehouse WHEN they have one or paying $150 for a new battery and the same for a new charger.

 

Here is my parts list and cost for those interested:

$3.99 - Radio Shack 4"x2"x1" ABS case enclosure

$3.49 - 2.1mm x 5.5mm DC jack chassis mount from Radio Shack

$1.12 - (2) 3/4" x 6-32 Aluminum Spacers from ACE hardware

$0.24 - (2) 3/8" x 6-32 cross tip screws from ACE hardware

$1.04 - (2) 6-32 hole size wire connectors from ACE hardware

????? - Solder lying around the house

????? - Red and Black 16 gauge solid wire lying around the house

????? - Electrical tape to wrap spacers in lying around the house

$31.99 - 9.5-20v 2-3A Laptop AC adapter from Fry's 

------------------------------------------------------------------------------------------

$41.87 + tax and labor 

 

Not too bad, me thinks.

 

Thank you to Zac for your help and advice.


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#7 Zac Fettig

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Posted 12 May 2014 - 07:57 AM

No problem! Glad to help. And I always enjoy seeing classic equipment up and running. It looks pretty good!

 

Does the laptop power supply provide enough current to start the camera? I've never owned a CP-16 (although somehow I ended up with a Nikon-to-CP adapter in my parts bin: waiting for the day I get my hands on a CP-16R). I think it's supposed to be 20VDC, although I might be wrong, which would put the power around the same as the Arri. (8V*6A=48W, 20V*2.4A=48W). Just curious.


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#8 Matthew W. Phillips

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Posted 12 May 2014 - 09:55 AM

Does the laptop power supply provide enough current to start the camera? I've never owned a CP-16 (although somehow I ended up with a Nikon-to-CP adapter in my parts bin: waiting for the day I get my hands on a CP-16R). I think it's supposed to be 20VDC, although I might be wrong, which would put the power around the same as the Arri. (8V*6A=48W, 20V*2.4A=48W). Just curious.

Yeah, I ran a 100 ft dummy roll through it and the lost sync light never comes on except for the first second after hitting the switch and the last second when turning it off (which it does even with the regular battery pack.)

 

The way I knew what to do is because I have an official battery (cracked and beat up but still works; albeit no charger) that has the specs on it. It showed which was positive and negative, and it said 20VDC and 550 mAH. I had heard that a new celled battery can get you at least 3 400' rolls worth of charge (approx 30 min) so I just doubled that to assume it draws about 1AH. This laptop charger can do 40w continuous and 50w peak so the 2-2.5amps should be plenty under the circumstances. I suppose if one wanted to be cautious, they could step up to the 75 or 90w models that can go up to 4 amps or more.


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#9 Patrick Lewis

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Posted 10 January 2016 - 12:07 AM

Sorry to resurrect this thread. Can anyone provide the polarity of the battery pins on the camera? I'd like to rig up a power source of my own, but I don't have a battery for reference. Don't worry, I have an engineering degree, so I won't destroy anything, and I know a thing or two about circuits.
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#10 Patrick Lewis

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Posted 10 January 2016 - 07:27 PM

Figured it out by finding this photo. For reference, here is a link to it. I do not own this photo. Came off of eBay. Looks like positive is the top prong on the camera.

https://www.dropbox....82/$_3.JPG?dl=0
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#11 Patrick Lewis

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Posted 12 January 2016 - 11:37 PM

Call this a prototype, but if you're interested in rigging up a battery, two 9.6 volt packs wired together in series works like a charm. These little blue crimp connectors from the hardware store slip right on the terminals on the camera just enough to stay put. I used Velcro to hold the batteries on. Probably not the best placement. Though. See image.

https://www.dropbox....114070.jpg?dl=0
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