Batteries and power supplies�

[Jay Taylor]

Hey guys,

 

So rather then sell my camera, I got myself a Norris system. The norris needs 12-24 vdc. What does this mean? Okay, so 12-24 volts, and dc, meaning battery, right? But why the range? Why 12-24? Are some functions more power hungry then others? If I hook up a 24v battery, will it fry the motor if I'm only using 12v functions?

 

Eventually I'll be getting a Fries motor for the camera, and it uses a 30vdc. I can't seem to find these anywhere. It also says that at 24fps, the motor uses 2 amps. At 120fps, it uses 10 amps. Do you have to power down the battery for 24fps?

 

So obviously I'm clueless about the battery, power supply thing here. Can someone explain how this stuff works, and above all, where do I buy these batteries? Or could I somehow build a battery pack? And how?

 

I read an article on Ron Dexter's website, but I'm still confused.

 

HELP!

 

Jay

[Bruce Taylor]

I don't know anything about the Norris system, but I know a little about batteries. Is this Norris system variable speed? If so, it may need more voltage (24v) for the higher speeds (loads). My Russian cameras willl run with 18-24v. The 24v is needed for running the higher speeds (like 40fps), but I can run it with 24v power at any lower speed as well which I often do for convenience and battery life. With an 18v supply they are happy to run at 24fps as I imagine the Norris will be.

 

I have put together some very powerful and inexpensive battery packs using gel cell batteries I get from the automotive battery distributor Interstate, though you can pick them up at many places. They are most common in 12v, so you can wire them in series for 24v, or in parallel for 12v. I picked up a boat battery case, 2 of the biggest 12v gel cells that would fit side by side in it and a rapid charger for about $170, the battery pack itself being about $100 of that.

 

I'm sure the Norris system has some amperage specs too (probably on the plate with the voltage requirements), I can't remember the formulas off the top of my head but it's easy to find the watt/amp/voltage/amp hour formulas on the 'net. On the other hand I figured if these batteries could run some fairly big consumers (like garage openers and other machines) they could handle a film camera, so I just guessed and got some big batteries. If you need more power, you can just get more batteries and hook them up in series.

 

You'll be safe with voltages between 12 an 24 volts.

 

Bruce

[Jay Taylor]

Hey Bruce,

 

The Norris is actually an intervalometer/single frame system. I should probably contact Norris directly to see about how many amps are required since it's nowhere on the motor itself.

 

How do you go about wiring a couple 12v batteries together? I'm sorry, I don't know much of anything about electronics!

 

Jay

[timHealy]

The norris needs 12-24 vdc. What does this mean? Okay, so 12-24 volts, and dc, meaning battery, right? But why the range? Why 12-24? Are some functions more power hungry then others? If I hook up a 24v battery, will it fry the motor if I'm only using 12v functions?

 

Hey Jay,

 

Basically if something says it needs 12 to 24 volts it means it will run with power between 12 and 24 volts. If you give it 11 volts of less it won't work (actually it may until the voltage drops a little more) and if you give it more than 24, you may fry the motor or the electronics or both. If you give it 19 and half volts it will work. There are no user 12 volt and 24 volt options. Actually some items may have a switch to put it in the 12 volt mode or 24 volt or there may be different inputs for the two.

 

Best

 

Tim

[timHealy]

How do you go about wiring a couple 12v batteries together? I'm sorry, I don't know much of anything about electronics!

 

Hey Jay,

 

If you don't know much about electricity I would read a book or do research online before playing with batteries and your intervalometer.

 

But basically when you wired DC batteries in series the voltage becomes cumulative. two 12 volt batteries wired in series becomes a 24 volt power source.

 

When you wire two batteries in parrellel the voltage remains the same but will last longer. two 12 volt batteries in parrellel will put out 12 volts.

 

and this is all DC.

 

Best

 

Tim

Edited June 7, 2008 by timHealy

[Jay Taylor]

Hey Tim,

 

Thanks for the information. It's starting to make a little more sense! I'm definitely not going to hook up anything until I can be sure I'm not going to destroy my equipment.

 

Are there any books or websites that you would recommend?

 

Also, would it be easier to just use some sort of dc to ac converter in order to just plug it into the wall? How would that work? Anything to look out for?

 

Jay

[Bruce Taylor]

Also, would it be easier to just use some sort of dc to ac converter in order to just plug it into the wall?

 

Do not do that unless you know a lot more about the motor, electronics and power supply!! Yes, "some sort" of ac to dc converter will work, but you need to know which one. Many ac to dc converters are much too "dirty" to use to power dc equipment, i.e. they leave a significant part of the ac sine wave in the signal that can damage dc electronics.

 

So it's probably cheaper, easier and safer to use batteries. I just went out to check and here is what I have for a 12 and 24v power supply that lasts a very, very long time before it is discharged. From Interstate Battery I got the Small U1 battery case, 2) BSL1105 sealed agm batteries which fit well inside the case, and a CTEK Multius 3300 charger (it's a "smart" charger). If you wire them in parallel you get 12v, in series you get 24v. The batteries come with standard spade connectors so you can get some wire and connectors at Radio Shack and put it all together.

 

http://www.hvacmechanic.com/basic_electric...20OF%20CIRCUITS

 

This is a website I found that has the basics you need on circuits. Let me try to write it out here too: To get 2 12v batteries to make 24v, you wire one negative connection to a positive on the 2nd battery, then use the single remaining terminals (one on each battery) for your output. Bingo, 24v. For one double strength 12v battery, wire the batteries positive to positive and negative to negative and take your 12v power from either terminal. Get yourself a cheap volt-ohm meter too, then you can double check your work to be sure you've done it correctly and have the polarity right before you hook it up to anything.

 

Good luck!

 

Bruce

[Jay Taylor]

Hey Bruce,

 

Wow, thanks so much for all the information! I'm learning. :)

 

How long could I expect the battery to last if I was only shooting single frame animation?

 

Does the amperage requirements affect which batteries you can use? For example, the batteries you listed are rated at 12Ah. If the Norris required less then that, would it cause any damage to use a battery with more?

 

Now I'd be interested in figuring out how you'd get a 30v battery for a Fries motor. I don't think I've seen any 15v batteries, so how would you get 30v? I've seen a lot of rental places that have the Fries cameras, and the batteries they include seem to vary. I've seen 26v, 28v, 30v, and 36v batteries, all supposedly working with the Fries motors. Why would this be?

 

And hopefully one last question! Is it possible to run both the norris and the video tap off the same battery? Or would it be better to have dedicated power for each?

[timHealy]

Are there any books or websites that you would recommend?

 

I would start by reading some basic electricity books for residential and commercial buildings. That's all 208 and 240 volt 3 phase and single phase AC systems in the US. That is the basic stuff. Don't worry about anything past that like Delta Wiring in large transformers and the like.

 

For film I would suggest the Harry Box book where he talks about electrical systems and set ups.

 

But some sort of basic electrical engineering books that talks about resistors and electronics. I am not an electrical engineer so I can't recommend anything but it would be helpful for you to do some work there too.

 

Like Bruce said you can probably get a 120 volt AC power supply that works with the Norris unit. I would call them and just buy one from the source so you don't have to try and figure it out.

 

Someone with more experience could build one but you aren't ready for that.

 

You may be able to use the same battery to power the video tape but when the motor runs you may have grounding issues or mechanical motor interference in you image. There is only one way to find out.

 

 

 

Best

 

Tim