Newbie 12v meltdown, please help.

[MartyB123]

Hi all, and thank you in advance of any helpful replies I receive.

My problem is, I got a 12v cctv camera that uses 3g/4g network to view from my android, I wanted to put it in a remote area with no electricity or wifi to try catch somebody vandalizing my property.

The cctv came with a 220v to 12v 1000mA plug in adapter, since I couldn't use this I bought a motorbike 12v 8.4Ah 135A (YUASA YTX9-BS) and cut a length of cable with jack plug attached, connected the ends of this cable to the battery and then plugged in the cctv to the battery.

It immediately start to smoke, I unplugged it, I opened the camera up to find lots of really thin melted wires, possibly even melted the entire length of wire from plug to camera.

I think I can re-solder new wires on, but will any of the circuitry be damaged, and if I can rewire what should I put in between the + of the battery and camera?, a resistor?

Any help really appreciated.

 

[hevans1944]

Sounds to me like you reversed the polarity when you wired the motorcycle battery to the camera... a typical newbie mistake since you probably didn't check the polarity of the "220v to 12v 1000mA plug in adapter" with a multimeter before trying to substitute it with a battery.

I am guessing, because of the smoke and melted wiring, that the CCTV camera is now "bricked" and beyond a cost-effective repair.

 

[Audioguru]

You probably put the connector on with backwards polarity, the positive on the battery wrongly connected to the negative of the circuit and vice-versa. The circuitry is ruined.

 

[MartyB123]

Sounds to me like you reversed the polarity when you wired the motorcycle battery to the camera... a typical newbie mistake since you probably didn't check the polarity of the "220v to 12v 1000mA plug in adapter" with a multimeter before trying to substitute it with a battery.

I am guessing, because of the smoke and melted wiring, that the CCTV camera is now "bricked" and beyond a cost-effective repair.

Thanks for the reply.

If I didn't wire the polarity wrong should there have been no problem with too much ampage?

 

[MartyB123]

You probably put the connector on with backwards polarity, the positive on the battery wrongly connected to the negative of the circuit and vice-versa. The circuitry is ruined.

Thanks!

 

[MartyB123]

You probably put the connector on with backwards polarity, the positive on the battery wrongly connected to the negative of the circuit and vice-versa. The circuitry is ruined.

In the correct polarity there should be no issues running this camera directly off this battery?

 

[BobK]

Amps are something a battery can supply. It only supplies them if what is connected needs them. You can always use a power supply with a higher current rating than the device requires, but not the reverse. The the voltage must actually match the required voltage (or be very close.)

I agree that you reversed the polarity.

I did so recently on a little board I had made with a microcontroller and LED strip. I was lucky in that a PCB track became an unintentional fuse and the rest of the circuit survived. You might not have been so lucky.

Bob

 

[MartyB123]

Amps are something a battery can supply. It only supplies them if what is connected needs them. You can always use a power supply with a higher current rating than the device requires, but not the reverse. The the voltage must actually match the required voltage (or be very close.)

I agree that you reversed the polarity.

I did so recently on a little board I had made with a microcontroller and LED strip. I was lucky in that a PCB track became an unintentional fuse and the rest of the circuit survived. You might not have been so lucky.

Bob

Thanks, It sounds like I fried my board so............

 

[hevans1944]

Thanks for the reply.

If I didn't wire the polarity wrong should there have been no problem with too much ampage?

Circuits consume as much current or "ampage" (to use your terminology) as they need, NOT the amount of current their power source is capable of providing.

There would have been no problem if you had wired it with the correct polarity, no matter how much current the battery was capable of providing. However, a motorcycle battery is capable of providing much more than the 1000mA current output of the "220v to 12v 1000mA adapter," so it had no problem smoking your camera and melting wires.

BTW, fuses are used to protect wires from melting. Clearly your CCTV camera didn't have one. Fuses, however, are not intended to protect components from inadvertent application of incorrect voltages and polarities. There are other circuit components (diodes, resistors, crow-bar circuits, etc.) that can accommodate such eventualities, but most of the time it is not worth the cost to add them to commercial gear because it makes the cost to the consumer non-competitive with gear that does not include "idiot-proof" features. Besides that, better "idiot proof" circuits only guarantee that better idiots will come along to defeat them. It's a losing battle for engineers.

I am not implying you are an idiot, so do try to learn from your mistake. Make sure the voltage and polarity are correct before attempting to power up any equipment, especially if you are using a different power source than the original equipment manufacturer (OEM) specified.

Your use of a motorcycle battery was both logical and desirable for remote operation. Next time, make sure it is wired in correctly! And check its state of charge frequently, so as not to allow it to "go flat" which greatly reduces the lifetime of lead-acid storage batteries. It would be a good idea to have two motorcycle batteries that you alternately swap at the remote site, bringing one back for re-charging on a weekly basis or whatever interval is necessary to keep the battery at the remote site from "going flat."

Good luck identifying and apprehending those vandals. Make sure your video is "time and date stamped" for use as evidence in a court of law. If you recognize the individuals responsible for the vandalism, please don't confront them. Instead, call the police and show the police your video evidence.

 

[Hopup]

If you are using that camera 24/7 then you probably need much bigger battery than 8.4Ah. I would estimate that your camera consumes between 200-500mAh or more than that.

 

[MartyB123]

If you are using that camera 24/7 then you probably need much bigger battery than 8.4Ah. I would estimate that your camera consumes between 200-500mAh or more than that.

How long roughly running 24hrs would that battery last?

 

[Hopup]

10-30hours with that battery, if the camera is constantly connected to 3G/4G.

 

[hevans1944]

There are CCTV systems used by wildlife photographers and hunters that only consume insignificant amounts of power until a passive infra-red (PIR) motion sensor triggers them to record. Recording time can be either a predetermined fixed interval, or continuous if motion is detected. You might want to consider going the "record now, view and prosecute later" route to conserve battery energy. Having a continuous 3G/4G connection will eat up batteries.

Another possibility (depending on range) is to integrate either an xbee, zigbee or Bluetooth transceiver with the camera and a PIR motion detector. The transceiver would transmit an alert to you when the PIR motion detector is tripped, allowing you to issue a command to activate 3G/4G transmissions and another command to stop them if it turns out to be a "false alarm."