Options for Powering a Special 12V/24V Light

[reg]

I'm in the process of purchasing a LiFePO4 battery, and one of the uses is a bit unusual.

I plan to use the battery, in part, to provide power to a light fixture that is widely used in still photography and film production. The fixture won an Academy Award for technical achievement because of the control that it provides when aiming and focusing light. The photography and film worlds are rapidly moving to LEDs, but this light still has its place.

The light fixture has a short cable ending in a male XLR socket to receive power. AC can be used for incandescent lamps up to 150W. A battery can also be used. The fixture is natively 12V for incandescent lamps up to 100W and 24V for 150W lamps.

I am interested in understanding the pros and cons of three ways of using a LiFePO4 battery, or for one option two batteries, to provide power to this fixture when using a 24V 150W lamp.

Option #1: Use a 12V LiFePO4 battery and an inverter. The main pro is that I could use the light fixture's AC power supply, which I already have. However, this option involves the inefficiency of converting the battery's DC power to AC and then back to DC.

Option #2: Use two 12V LiFePO4 batteries in series to provide 24V of power. The light's manufacturer offers 12V accessories, but not 24V, to power a lamp up to 100W. These include an automobile "cigarette" cable, and a cable, no longer available, that has been used historically to power this light from an NiMH battery pack. I think that I would want a "box" to regulate the battery's 24V. The box would terminate in an XLR female connection to the light's male connection.

Option #3: Use a 12V battery and a box to step up the voltage to a regulated 24V. I have seen boxes, made for example by Dork, that apparently can do this. I would like to learn what's involved and what the downsides are.

On options #2 and #3, I may contact the German company that makes this light. I'm hoping that comments here will make that unnecessary, or at least make me better informed if I call or write. If the practical answer is to use an inverter, despite an efficiency loss, I'm happy to go that route.

Thanks very much for your comments.

 

[45North]

I'm in the process of purchasing a LiFePO4 battery, and one of the uses is a bit unusual.

I plan to use the battery, in part, to provide power to a light fixture that is widely used in still photography and film production. The fixture won an Academy Award for technical achievement because of the control that it provides when aiming and focusing light. The photography and film worlds are rapidly moving to LEDs, but this light still has its place.

The light fixture has a short cable ending in a male XLR socket to receive power. AC can be used for incandescent lamps up to 150W. A battery can also be used. The fixture is natively 12V for incandescent lamps up to 100W and 24V for 150W lamps.

I am interested in understanding the pros and cons of three ways of using a LiFePO4 battery, or two of them, to provide power to this fixture when using a 24V 150W lamp.

Option #1: Use a 12V LiFePO4 battery and an inverter. The main pro is that I could use the light fixture's AC power supply, which I already have. However, this option involves the inefficiency of converting the battery's DC power to AC and then back to DC.

Option #2: Use two 12V LiFePO4 batteries in series to provide 24V of power. The light's manufacturer offers 12V accessories, but not 24V, to power a lamp up to 100W. These include an automobile "cigarette" cable, and a cable, no longer available, that has been used historically to power this light from an NiMH battery pack. I think that I would want a "box" to regulate the battery's 24V. The box would terminate in an XLR female connection to the light's male connection.

Option #3: Use a 12V battery and a box to step up the voltage to a regulated 24V. I have seen boxes, made for example by Dork, that apparently can do this. I would like to learn what's involved and what the downsides are.

On options #2 and #3, I may contact the German company that makes this light. I'm hoping that comments here will make that unnecessary, or at least make me better informed if I call or write. If the practical answer is to use an inverter, despite an efficiency loss, I'm happy to go that route.

Thanks very much for your comments.

Need more info.
Link?

 

[DThames]

It seems you can run the light at 24v, off of two batteries in series. You would need 24v lamps for the light. So do you need 12v for some reason other than the light itself? If not, just 24v to 24v lamps.

 

[reg]

Need more info.
Link?

Delighted. See Classic Series, DLH4, page 33 et seq.
: https://www.dedoweigertfilm.de/webl...a1985b322ec7ed7d/DL-CAT2011N1_Eng-HighRes.pdf

This is an August 2020 video by an accomplished cinematographer on using these lights with a fairly new lighting system called Lightstream:

This is a nuts and bolts video:

 

[reg]

It seems you can run the light at 24v, off of two batteries in series. You would need 24v lamps for the light. So do you need 12v for some reason other than the light itself? If not, just 24v to 24v lamps.

Yes, as a practical matter if you have AC or 24V there's no reason to use anything but a 24V 150W lamp. When desired, one can dim the 150W lamp.

However, 12V has historically been useful for battery-driven mobile, portable use.

 

[DThames]

So how long would you want to run the light before the battery needed charging? That will help determine your battery size.

 

[reg]

So how long would you want to run the light before the battery needed charging? That will help determine your battery size.

For reasons of weight and size, I'm going with 25Ah to 50Ah battery capacity. When battery powered, I plan to use only one 150W light. The issue here is the mechanics of running that light.

I have another thread on battery capacity and brand:

Need Recommendations for an Off-the-Shelf 25Ah to 50Ah LiFePO4 Battery: https://diysolarforum.com/threads/n...the-shelf-25ah-to-50ah-lifepo4-battery.20267/​

 

[reg]

Update:

I've purchased a Lithium Werks 12V 40Ah battery (Valence U-Charge U1-12RT) and a Morningstar SureSine 300W inverter.

This means that option #1 in the first post is now covered. Still very interested in input on option #3.

Thanks

 

[DThames]

Option #3, a 12v to 24v boost converter...Something like this might work for you. Plan to need a fan for it. You will be close to the max input amps at 150w.