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12v DC-DC converter for camera?

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Vaughn

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I have a 12v Wireless camera (500ma w/IR lights) and I use an 8 AA battery cage from RadioShack to make a 12v Battery. I fill it with AA NIMH batteries. This is all mounted on an RC car.

I would like to regulate the voltage so the camera always gets a clean study supply of 12v. I have read about DC-DC converters for most of the morning, but I am not looking build anything. I can solder a couple wires, but that's about it.

Is there something super-easy that will work for me? I am looking for a product, not components to build a board or something. I would realliy like something I could splice or solder between the battery pack and the camera...

I know there are other options like LiPo's boosted to 12v, but I am already overwhelmed and would like to get this working before I tackle something else.

I also have a 9v wireless camera running off of a single 9v NiHM battery that I would like to do the same thing for. I wired 4-9v batteries in parallel but it introduced too much noise and of course was not regulated.

Thank you for any help, I am sure you guys hate it when us know-nothing come in with questions like this, but it is hard to sort through everything on the net, so thanks!

Vaughn
www.vCrib.com
 
For a start you need TEN NiMh batteries to give you 12V, eight only give you 9.6V - so use ten and you will probably be fine!. Use the 8 for your 9V camera, that should be OK for that.

I doubt you need anything better!.
 
The reason is the the standard cell voltage of an NiMH cell is 1.2V not 1.5 as is typical with an alkaline cell. This small point confuses many people who expect a AA cell of any chemistry to be 1.5 Volts. Sorry friends, it just ain't happening.
 
Thanks for the fast info.

I read somewhere else this morning where someone mentioned using 10 and I just read past it.. That is great to know, I just hope I can get a cage that holds 10 now from RS so I can test tonight.

So now lets say I am using the proper number of cells, would a DC-DC converter still help clean up the power going to the camera and possibly give me a cleaner picture?

Also, things like the Transmitter for my RC car uses 8 AA, since I am using NiMH now, that transmitter is running on 9.6v instead of 12v. So would that hurt the transmittion range or anything else I should be worried about? I never knew using NiMH would give me less voltage in any of the devices I use them in, have to double-check everything as I actively use over 160 AA & AAA batteries in my house at any given time.

Thanks again guys,
Vaughn
www.vCrib.com
 
Papabravo said:
The reason is the the standard cell voltage of an NiMH cell is 1.2V not 1.5 as is typical with an alkaline cell. This small point confuses many people who expect a AA cell of any chemistry to be 1.5 Volts. Sorry friends, it just ain't happening.
NOPE!
An alkaline battery cell also isn't 1.5V over most of its life. The voltage of a "1.2V" Ni-MH cell is higher than the voltage of a "1.5V" alkaline cell over most of their lives. The voltage of the alkaline cell is 1.5V only for a moment before it is used.
 

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audioguru said:
NOPE!
An alkaline battery cell also isn't 1.5V over most of its life. The voltage of a "1.2V" Ni-MH cell is higher than the voltage of a "1.5V" alkaline cell over most of their lives. The voltage of the alkaline cell is 1.5V only for a moment before it is used.

Ack! So then isn't a DC-DC converter what I want still? Regardless of the batteries' voltage, I would always get 12v out?

I know what you are saying... My 9-volt batteries drop fast too, but I definitly always want 9 volt output from them... I want regulated voltage, and batteries don't offer that, so I am wanting to improve that. I know a linear system is not what I want, and that a switched Boost converter sounds like what I need, but in a ready-to-use format. Any links for a product like that?

Eventually I will use LiPo, but I wanted to get some experience before I burn everything I own up on LiPos.


Thanks,
Vaughn
www.vCrib.com
 
Vaughn said:
Ack! So then isn't a DC-DC converter what I want still? Regardless of the batteries' voltage, I would always get 12v out?

NiMh are decent batteries, as long as you use the correct number of them then I don't see as you need anything else.

Certainly, if you didn't know that NiMh are only 1.2V you don't want to be trying to build switchmode converters!.

I know what you are saying... My 9-volt batteries drop fast too, but I definitly always want 9 volt output from them... I want regulated voltage, and batteries don't offer that, so I am wanting to improve that. I know a linear system is not what I want, and that a switched Boost converter sounds like what I need, but in a ready-to-use format. Any links for a product like that?

I don't see any need - use proper numbers and types of batteries, and everything should be fine!.
 
Nigel Goodwin said:
Certainly, if you didn't know that NiMh are only 1.2V you don't want to be trying to build switchmode converters!.

heheh SOOO true! that was my whole point in asking if there was something pre-assembled that I could just put inline. Just for my simple mind, could you say in clear terms that there is no pre-assembled way to get regulated voltage from batteries, regardless of my needs or abilities or cost?


Regardless of that, you have been very helpful and I appriciate you helping the helpless =)

Vaughn
 
Nigel Goodwin said:
Certainly, if you didn't know that NiMh are only 1.2V you don't want to be trying to build switchmode converters!.

Who said anything about building one, he could always buy and off the shelf one if he wanted really wanted to use one, (I'd recommend that anyway).

In this case I don't see why a DC-DC converter is required, for all you know there could allready be a switch mode PSU i built into the LED light.
 
My Plants Watering Watcher-2 and 3V Ultrabright Chaser projects work fine when their 3V alkaline batteries run down to only 2V over their lives and you hardly notice the LEDs dimming a little. But when the voltage drops less than 1V per cell, it is dropping quickly and the LEDs are operating at their threshold voltage.
 
Vaughn said:
heheh SOOO true! that was my whole point in asking if there was something pre-assembled that I could just put inline. Just for my simple mind, could you say in clear terms that there is no pre-assembled way to get regulated voltage from batteries, regardless of my needs or abilities or cost?

I can't say I've ever seen such devices for sale?, basically there's not a great deal of use for them - and I don't see as you have any requirement for them either?.

If an item requires an extremely well regulated supply you design it accordingly - so it's really a design decision, not a later modification.
 
Thanks everyone. I found the information I was looking for. Here are my findings if anyone is interested:

Tutorial:
https://www.rc-cam.com/dc-dc.htm

Part:
https://www.electro-tech-online.com/custompdfs/2006/06/slts026b.pdf

Use:
"That old RC-CAM project used the raw voltage for the 5V CCD camera. However, the video transmitter's 12V was provided by the stepped up (boosted) voltage from the PT5041 VReg. This arrangement was an immediate hit among the R/C video hack community. It is still a very popular Boost Switching VReg for R/C video applications. Digikey.com stocks them. "

Additional Instructions:
"You use a .1uf cap between voltage in and ground and a 10uf between th eoutput and ground. There's a diagram in the PDF file. I use tantalum caps just for reliability and small form factor. I solder them right onto the leads of the regulator and then solder in standard RC connectors for voltage in and out. (Other connectors are fine too) Then I carefully dab in some hot glue, then cover the whole thing in heat shrink. If you application gets too hot, it would be better to leave it open and put it on a heat sink. "


I realize that information is not necessary to power my 12v camera from AA batteries, but it is what I was asking for as a product and will allow me to get away from using the AA batteries and power both cameras and the av tx off of 1 battery.

I just wonder if that will clean up enough noise that I can use the same battery as the RC's ESC runs from... hmmmm

Well thanks guys,
Vaughn
 
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