Battery Powers A Camera But Not A Few Power Transformers

Thread Starter

nassausky

Joined Feb 15, 2018
9
Hi All,

I had something strange happen to me lately. I ordered a rear view camera 12v car camera. I have plans on using the device in place of a doorbell so need to use a 12v transformer. I tried 3 different 110VAC to 12VDC transformers and none of them power up the camera but a backup UPS dual 6v battery which makes 12V in series does power up the camera.

One transformer rated at 12VDC, 5.0 Amps, 60 Watts.
Voltage reads 12.25VDC on a Voltmeter.

One transformer made for 9 indoor security cameras rated at 12VDC, 5 Amps (Max 1.1Amp/Channel)
Voltage reads 11.2VDC on a Voltmeter.

One transformer rated at 12VDC, 1.0 Amp, 20 Watts
Voltage reads 16.2VDC on a Voltmeter.

The Dual 6V Battery in Series
Voltage reads 15.29VDC on a Voltmeter.

What am I missing? How can I get the 12volt car camera to work indoors without using the backup battery.



(I have 2 of the same manufacturers camera and both are the same but I have another camera by a different manufacturer that works on an indoor transformer. This other camera does not have the option to aim the lens like the first model so I'd prefer not to use it.)
Thanks
 

#12

Joined Nov 30, 2010
18,210
I think we start with communication as the first problem. Transformers do not work with DC, but you can make DC out of what the transformer does work with. For instance, start with the AC voltage the transformer will produce and add diodes and capacitors until the result is DC. Something that is labeled to output DC is not just a transformer because it already has diodes and capacitors to make DC.

Another aspect is that a 12 volt AC output from a transformer changes to something like 15.6 volts DC after the diodes and capacitors. This is usually not a problem with automotive loads because a car doesn't provide 12.00 volts. It provides something in the range of 12.6 VDC to 15.5 VDC.

So, let's back up a little bit and get specific about what you have been plugging into the wall outlet.
 

ElectricSpidey

Joined Dec 2, 2017
1,142
Well the OP did say he used a meter to check the voltages, and I have to assume "transformer" just means power supply. (unless they don't know how to set a meter properly)


Just guessing here….but your camera may be designed to run at the higher voltages that are usually present in a car.


T1 & 2 may not produce enough voltage.

T3 may not produce enough current, or it’s got too much ripple.(16 volts probably means it’s not regulated)

And the batteries produce enough of both.


Just a guess based on info provided, could be something else altogether.
 

Thread Starter

nassausky

Joined Feb 15, 2018
9
I think we start with communication as the first problem. Transformers do not work with DC,
I'm sorry how I thought I was clear that all were 110VAC and 12VDC output.
Sorry let me clarify. All of them take input of 110VAC and are supposed to output 12VDC.
1) Plugs into an 110 V AC Outlet
2) Plugs into an 110 V AC Outlet
3) Plugs into an 110 V AC Outlet

Transformer1.jpg Transformer2.jpg Transformer3.jpg
 

Thread Starter

nassausky

Joined Feb 15, 2018
9
Well the OP did say he used a meter to check the voltages, and I have to assume "transformer" just means power supply. (unless they don't know how to set a meter properly)


Just guessing here….but your camera may be designed to run at the higher voltages that are usually present in a car.


T1 & 2 may not produce enough voltage.

T3 may not produce enough current, or it’s got too much ripple.(16 volts probably means it’s not regulated)

And the batteries produce enough of both.


Just a guess based on info provided, could be something else altogether.
I like that answer. Any recommendation about how I can shop for a "Power Supply" that can have enough Voltage and Current and doesn't ripple.

:)
 

ElectricSpidey

Joined Dec 2, 2017
1,142
First you need to establish what the problem is exactly. Finding a suitable supply is no problem.

I don't suppose you know somebody with a nice adjustable bench supply?
 

WBahn

Joined Mar 31, 2012
25,748
I'm sorry how I thought I was clear that all were 110VAC and 12VDC output.
Sorry let me clarify. All of them take input of 110VAC and are supposed to output 12VDC.
1) Plugs into an 110 V AC Outlet
2) Plugs into an 110 V AC Outlet
3) Plugs into an 110 V AC Outlet

View attachment 146086 View attachment 146087 View attachment 146088
Those are NOT transformers. They are power supplies. Every day, lay use of the term "transformer" may cover it, but in a technical conversation about these things, the term "transformer" has a very specific meaning.

So thanks for clearing up that confusion.
 

WBahn

Joined Mar 31, 2012
25,748
I like that answer. Any recommendation about how I can shop for a "Power Supply" that can have enough Voltage and Current and doesn't ripple.

:)
To do that, we need to know what the requirements are for the thing they are going to power. What is the required voltage and current for this camera? Look at the specs. Or at least provide the make and model number so that someone here might look for the information.
 

#12

Joined Nov 30, 2010
18,210
OK. We have determined that you are using AC to DC converters. The photos you posted are, by coincidence, arranged in order of quality. Now to the question by WBahn: What does the camera want (in terms of voltage and current)?

Some power supplies don't manage start current surges very well. Some of them will even, "safety out" because of the start surge.

It would be helpful if you declared what loads are connected when you make your DC measurements. For instance, the converter which measured at 16.2 volts DC suggests that no load was connected when you measured.

I'm going to bug out now because I have other chores to do today and you have a veritable parade of helpers assisting right now.
 

dendad

Joined Feb 20, 2016
3,518
I wonder if one was connected in reverse or the over volts from the unregulated LiteOn supply has popped the camera.
Does the camera still work?
Otherwise it does not make a lot of sense.
 

Thread Starter

nassausky

Joined Feb 15, 2018
9
Thanks for all the input. The camera still works hooked up to the batteries.

No info in the manual on current requirement. Attached the only spec sheet.CameraManual.jpg

Don't think I am authorized to post the amazon link to the camera.
The model is
Zhongsheng Waterproof HD Night Vision NTSC Backup Camera, Rear/Front/Side View Camera without Scale Line 360D11


No load on the supply.
 

ElectricSpidey

Joined Dec 2, 2017
1,142
Looks like the current requirement is less than 100mA.

This is weird, because you would think the camera would have its own internal regulator, so it can operate over the automotive range of voltages.
 

Reloadron

Joined Jan 15, 2015
5,442
Were the voltages measured under load or no load. I have one of those backup cameras I yanked out of one of my trucks. They really do not use any current to speak of. I found the camera and the display has to be around here somewhere. My rough guess is maybe 100 mA camera and 200 mA for the display screen, well below 0.5 Amp total. If I could find that display I would check them. Granted some systems use more than others but I doubt any use much power to speak of. They also run off automotive system power which is not quite the cleanest power going.
but a backup UPS dual 6v battery which makes 12V in series does power up the camera.
That is interesting as if the thing was defective or simply put broken it would not work at all. I would think it should work on any of the wall worts or supplies you posted. You are sure about the polarity?

Ron
 

spinnaker

Joined Oct 29, 2009
7,835
Hi All,

I had something strange happen to me lately. I ordered a rear view camera 12v car camera. I have plans on using the device in place of a doorbell so need to use a 12v transformer. I tried 3 different 110VAC to 12VDC transformers and none of them power up the camera but a backup UPS dual 6v battery which makes 12V in series does power up the camera.

One transformer rated at 12VDC, 5.0 Amps, 60 Watts.
Voltage reads 12.25VDC on a Voltmeter.

One transformer made for 9 indoor security cameras rated at 12VDC, 5 Amps (Max 1.1Amp/Channel)
Voltage reads 11.2VDC on a Voltmeter.

One transformer rated at 12VDC, 1.0 Amp, 20 Watts
Voltage reads 16.2VDC on a Voltmeter.

The Dual 6V Battery in Series
Voltage reads 15.29VDC on a Voltmeter.

What am I missing? How can I get the 12volt car camera to work indoors without using the backup battery.



(I have 2 of the same manufacturers camera and both are the same but I have another camera by a different manufacturer that works on an indoor transformer. This other camera does not have the option to aim the lens like the first model so I'd prefer not to use it.)
Thanks

Here is a question that was not asked. Why are you trying to use a rear view camera for a car and not a dedicated doorbell camera? There are plenty on the market.

Are you certain the polarity is correct? If camera works on the battery and power supply works that is the only thing it can be, aide multiple bad power supplies that can't take a load.
 

Thread Starter

nassausky

Joined Feb 15, 2018
9
Backdoor.jpg
Here is a question that was not asked. Why are you trying to use a rear view camera for a car and not a dedicated doorbell camera? There are plenty on the market.

Are you certain the polarity is correct? If camera works on the battery and power supply works that is the only thing it can be, aide multiple bad power supplies that can't take a load.
I've plugged in the power adapters so many times. I was thinking at first before finding the battery to use that the camera had the wire colors wrong. Only 2 wires for power coming out of the camera (remember also I have 2 cameras by the same manufacturer both working the same) which are red and black/red. Also remember I plugged it into the battery circuit and noted that the red is (+) and the black/red combo wire from the camera is (-). The wires coming from the power supplies are simple to determine their polarity also and they were connected correctly.


To answer the question about why these cameras. First I didn't want a wifi doorbell camera. Too much of a delay. Next unless you know a specific camera that can get drilled inside a 1" hole because it's mounting into a door frame which I'm also attaching a electric lock then I'd be happy to consider that as an alternative. The limit here is the width of the steel doorframe and the rock fascia beside it which I'd rather not have to rig up an L bracket for the camera.

Oh yeah my voltage testing is without a load. I don't do troubleshooting on electronics enough to tell you the best way to test a camera like this. Should I put a resistor in the load. Haven't had to do any calculations regarding circuits in years. I'm all ears. I just have a feeling it's requiring more than 12Volts DC and a cleaner signal than the power supply that was over 15 volts. Actually it started closer to 16 volts without load and started dropping in voltage as it was being tested by my voltmeter. Didn't notice this before and like I said I don't measure DC voltage enough to know the characteristics.

Did I make sense? Any more questions?
 
Last edited:

Tonyr1084

Joined Sep 24, 2015
4,509
I have some extra HID lighting systems from a car I sold. Funny, they won't fire up when I use my 13.8 V 19 A power supply. But they WILL fire up when I connect them to a small 12 volt battery; 12 V 20 A SLA battery. It could just be that those power supplies you're trying to use produce a period of power on / power off to maintain an average voltage (as most SMPS do) ( oh, SMPS means Switch Mode Power Supply). They work a lot like PWM, or Pulse Width Modulation. That means that some percentage of the time power is on and the rest of the time power is off. This happens at high frequency so that the average overall voltage depends on the percentage of time it's on versus off. Called "Duty Cycle". Your camera, designed to run on a pure DC source is not seeing a pure DC. Those wall warts (as we so often call them) are most often SMPS. Some older ones may be built around a REAL "Transformer" and rectifier circuit with filtering capacitors and some sort of regulator circuitry. But just about all I can get my hands on now-a-days is those darn SMPS wall warts. Even the one you have that doesn't hang on a wall is still a SMPS.

Many years ago when I was a kid (back when car radios still had tubes) (yeah, I'm old) I tried to run one of those car radios off of a 12 volt battery charger, which is basically a 12 volt transformer who's current is rectified to produce choppy 15 volts. The radio played but boy did it sound like hell. So I experimented with a filter cap. Someone told me I needed one. Not knowing ANYTHING about capacitors I tried putting a 16 volt electrolytic cap on the output after the rectifier. I think it was something like 0.1 µF, and did NOTHING to stop the hum. So I tried putting it on the transformer output. The darn thing survived, but did nothing to stop the hum. So (and I know a bunch of you guys are going to laugh your ars' off) I put the 16 volt electrolytic across the primary (120 VAC) of the transformer. Boy did I get an energetic response. And the hum just kept going.

Radios of that era are a lot more forgiving of their power sources than most modern electronics today. Today in an automobile, the equipment designed to work there expect a noisy and harsh electronic environment. But they're NOT expecting to see SMPS or PWM. Likely they won't work without a VERY SERIOUS filter capacitor. A capacitor that is approaching Battery Status. - - - By the way, I eventually solved my hum on my radio. I connected a car battery to it. The charger kept the battery charged and the radio played just fine after that. No, I wouldn't recommend you get a car battery for your backup camera security system that someone will probably pull off the wall. But if you DO go with a battery then get a small 12 volt battery that can give you 10 amps service as well as a battery charger that can keep that battery charged to 13.6 volts. And you'll be able to get a good five years of service out of that battery.
 

Tonyr1084

Joined Sep 24, 2015
4,509
Quickly wondering something here: Doorbell cameras - - - don't they sense motion and start recording? Or sense motion and send you a signal to watch the video? Running a backup camera 24 hours a day, 7 days a week, I wonder how long it will last. And how are you going to be recording the video? Do you have a DVR for it? Can your DVR (if you have one) accept the video feed from a backup camera? I honestly don't know the answers to those questions. So - - - .
 
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