Step Up Down Transformer? 7.2v - 12v

Thread Starter

Rob Gallo

Joined Apr 7, 2019
8
Can I power this device Wireless HDMI Transmitter which requires Power adapter specifications: AC 100V-240V 50 / 60Hz, DC 12V / 1.5A

https://www.ebay.com/itm/Wireless-HDMI-Extender-2-4G-5GHz-1080P-HDMI-Transmitter-Receiver-100-240V/113448095328?hash=item1a6a088e60:m:mivionM69RlKZa-Ri2hZjBQ

with this Sony battery Power: 7.2 V, 47.4 Wh, 6,600 mAh

https://www.sony.com/electronics/handycam-camcorders-batteries-chargers/np-f970#product_details_legacy_default

Can someone recommend a simple compact build for a first timer?

s-l1600.jpg

sku_331201_1.jpg
 

Yaakov

Joined Jan 27, 2019
1,604
Welcome to AAC. We can certainly help to make something work.

You could use a boost converter to bring the 7.2V up to 12. But you'd be better off using two batteries and a buck converter to drop the voltage.

If you plan to use this as an on-camera system for wireless video, I predict you will be very unhappy with it. It has no diversity reception, so fading is likely to be a serious problem for it is you move at all.
 

Yaakov

Joined Jan 27, 2019
1,604
Some points: you can't use a transformer to raise or lower DC voltages. A boost converter essentially makes AC for the DC and uses a transformer to raise the voltage, then converts it back to DC.

Mechanically, you could possibly use a battery plate like this, or something from Small Rig to mount the batteries:

https://www.amazon.com/dp/B01FYSD2Y8/
 

Thread Starter

Rob Gallo

Joined Apr 7, 2019
8
Some points: you can't use a transformer to raise or lower DC voltages. A boost converter essentially makes AC for the DC and uses a transformer to raise the voltage, then converts it back to DC.

Mechanically, you could possibly use a battery plate like this, or something from Small Rig to mount the batteries:

https://www.amazon.com/dp/B01FYSD2Y8/

Thanks YAAKOV!

I had no idea about that plate. I will get one.

What do you mean about no diversity reception. I need an inexpensive hdmi setup to display on a big scream. No concerned about resolution quality but drop outs are a no no.
 

Yaakov

Joined Jan 27, 2019
1,604
The 2.4 and 5GHz bands are extremely susceptible to multipath fading where reflected signals cause interference with the transmission. Diversity reception adds extra antennas to ensure the signal can be maintained.

The effect is extremely sensitive to position, so if you move, you will find nulls and peaks as you do.

Here, only for example, is what a pro version looks like:

https://www.bhphotovideo.com/c/product/1400454-REG/cinegears_6_200_ghost_eye_wireless_hd_sdi.html

You can test, perhaps it will work reliably in your situation, but I expect it will be a problem. I hope I am wrong.
 

Thread Starter

Rob Gallo

Joined Apr 7, 2019
8
Yes. I am trying to avoid that pro expense. Ill gibe this a try.

Would you suggest the adapter plate or wiring 2 of the sony batteries in series? Then would my voltage not be too high?
 

Yaakov

Joined Jan 27, 2019
1,604
Yes. I am trying to avoid that pro expense. Ill gibe this a try.

Would you suggest the adapter plate or wiring 2 of the sony batteries in series? Then would my voltage not be too high?
You have to figure out the actual power draw of the device to decide if one battery is sufficient. I would expect you need 2, in parallel, into the boost converter I linked, which will get you the 12V.

You will need a DMM (Digital Multimeter) to make voltage measurements when adjusting the boost module.

You should get a decent one, it can be a lifetime tool, and have many other uses over the years.
 
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Thread Starter

Rob Gallo

Joined Apr 7, 2019
8

Yaakov

Joined Jan 27, 2019
1,604
For my purpose using the composite video out would be suffice but it cannot be used at the same time as the hdmi out which i use for webcasting at the same time.

The device manufacture recommended this.
https://www.ebay.com/itm/1800-20000mAh-Rechargeable-Portable-Power-Li-ion-Battery-DC-12V-For-CCTV-Camera/173403787669?hash=item285fabd195:m:mIcBLBSiHuzyfT0nSy_fg1g

But I wanted to try using my Sony batteries if possible.
Well, you can certainly build a working pack from those batteries, plates (make sure you get the right one!), and buck-boost converters. You’d want a box for the module, and I would put DC barrel connectors on pigtails to plug onto the batteries and the device.
 

MisterBill2

Joined Jan 23, 2018
4,068
For much less money than those Sony batteries you can purchase a 12 volt 7 amp-hour gell cell battery and run your wireless link for several hours. You may also find some lithium batteries that will work, but they are more critical as to how they are recharged. That is the way to avoid the less than 100% efficiency of the power converters.
 

Yaakov

Joined Jan 27, 2019
1,604
For much less money than those Sony batteries you can purchase a 12 volt 7 amp-hour gell cell battery and run your wireless link for several hours. You may also find some lithium batteries that will work, but they are more critical as to how they are recharged. That is the way to avoid the less than 100% efficiency of the power converters.
Portability is a key requirement for this, @MisterBill2. In addition, the Sony NP batteries are ubiquitous in the industry, and are often used to power things like off camera lighting, etc.

If it was stationary, a VRLA battery would be a good choice, as you point out, because it will provide the 12V natively, and because it will have high capacity. But weight is a consideration.
 

MisterBill2

Joined Jan 23, 2018
4,068
A single package with the SLA battery would be more portable than tying a converter to the battery and having more pieces to carry. I routinely carry my HT around clipped to the pack that holds the 7AH battery. Of course, the pack does have a handy shoulder strap so that neither item needs a belt hook. That lets me run the HT on high power and assures reliable communication when I need it. It seems that most things are a trade-off somehow, and battery power is no exception. So it depends on just what the TS wants. Good news that there are choices available.
 

Yaakov

Joined Jan 27, 2019
1,604
A single package with the SLA battery would be more portable than tying a converter to the battery and having more pieces to carry. I routinely carry my HT around clipped to the pack that holds the 7AH battery. Of course, the pack does have a handy shoulder strap so that neither item needs a belt hook. That lets me run the HT on high power and assures reliable communication when I need it. It seems that most things are a trade-off somehow, and battery power is no exception. So it depends on just what the TS wants. Good news that there are choices available.
One aspect of those battery plates is that they are designed to be part of a camera “rig”, they have mounting hardware that can be used to put them on the cage, and battery swaps are trivial, so you can have charged spares. In that paralell configuration you could even do hot swaps if demanded.
 
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