5 Minute Temporary Power Supply

[johncassell]

Hi all,

can someone point me in the direction of a solution for this please..

I have a camera installed in my car which is setup to power on when the ignition is turned on. It turns off when the ignition is turned off.

I would like it to continue to receive power for a few minutes after the ignition has turned off. I guess there should be some sort of rechargeable battery in between the camera and the car battery which allows the camera to still receive power.

Only thing is most batteries will last much longer than 5 minutes and I don't want it recording for too long after I've turned off the ignition.

Any ideas?

Thanks
John

 

[plugwash]

No reason to use a seperate battery, you just need to find a permanent feed from the car's battery (there is usually one going to the stereo....)

As for actually implementing the delay a quick search for "12v delay off timer" finds some devices that look suitable.

 

[jamesmcbride]

Something like this would probably suit your needs http://www.ebay.co.uk/itm/TIMER-SWI...-Delay-Off-Switch-12V-ON-BUTTON-/270989991155

 

[johncassell]

Hi, thanks for those replies. the ebay link points to a kit that runs for a max of 20 seconds. Is a 5 minute timer too adventurous?

And if its connected to the permanent feed - assume it can still kick in when ignition is turned on?

Thanks again
John

 

[bernardgreen]

http://www.polevolt.co.uk/acatalog/info_74205.html

0 = 0.5 ... 10 sec delay off 5 = 0.5 ...... 6 hrs delay on
1 = 5 ...... 60 sec delay off 6 = 5 ...... 60 min delay on
2 = 0.5 ... 10 min delay off 7 = 0.5 ... 10 min delay on
3 = 5 ...... 60 min delay off 8 = 5 ...... 60 sec delay on
4 = 0.5 ...... 6 hrs delay off 9 = 0.5 ... 10 sec delay on

Terminal Connections:
Terminal 30 ---- Positive supply
Terminal 15 ---- Positive trigger input
Terminal 31 ---- Earth
Terminal 87 ---- NO relay contact
Terminal 87a -- NC relay contact

Price each: £29.95 (£35.94 Including VAT at 20%)

Other suppliers exist

 

[johncassell]

thanks very much for that. Hopefully have everything I need now.

Cheers
John

 

[ericmark]

There are timers made specially for cars to hold the head lights on for long enough for you to find the front door of your house and switch on house lights. I am sure you can use one of these to power the camera.

 

[Porque223]

Depending on the camera current draw there is an off chance that you can use a supercapacitor.

 

[Lectrician]

No reason to use a seperate battery, you just need to find a permanent feed from the car's battery (there is usually one going to the stereo....)

As for actually implementing the delay a quick search for "12v delay off timer" finds some devices that look suitable.

Most cars these days use some form of can-bus, and do not have the traditional switched 12v, illumination 12v, reverse 12v, handbrake 12v, speedpulse etc available at the radio any more. They just have a 0v, 12v and a can-bus +/-

You can get can-bus converters which will provide you with these outputs.

Can-bus has made it very easy for vehicle manufacturers to interlink control systems in cars more so than ever before. Every system in a car is a seperate, but interlinked by the digital Can-bus.

An example of this is "Hit reverse, and if you have your wipers on, the rear wiper will switch on itself". This was never a thought before until the two systems could speak to each other. It is a simple matter of programming now, rather than relays and logic.

You can now buy vehicle alarms that once would require you to wire a +12v, sw12v, 0v, 6 cores to central locking, 6 cores to elec windows, cores to bonnet, boot, drivers door, passengers door, imob to fuel pump, 2 cores to indicators etc. These days, +12v, 0v, +/- Can-bus. That's it, job done. All the signals are passed over the Can-bus.

Some vehicles have very little wiring to the rear light clusters - only the +12v, 0v and Can-bus. Nothing else is needed.

Can-bus vehicles can usually be identified by the tiny delay in operation. Turn your lights on, and they come on a fraction of a second later than you may expect.

We fit hands free kits and GPS tracking for some firms, and Can-bus adaptors are a god send in modern vehicles where a switched 12v is near impossible to find.

 

[flyingsparks]

Good informative post Lectrician, cheers. So basically modern cars use a PLC or smart relay to control everything (near enough).?

When my tow bar was fitted, I thought it would be easy enough to connect the lighting socket my self connecting into the light cluster at the back, but nope, they had to do some quite major operations on it all!

My van horn seems to have a mind of its own, if it hasn't been used for a while and you press it, it can take ages to work, perhaps 10 seconds or more, if its been used recently it is nearly instant, perhaps half a second delay. Not so good when some knob cuts you up and you want to blast them!

 

[Spark123]

Sounds more like your horn needs hit with a hammer than an electrical issue!
Can-bus has it's place, used in things as simple as vehicle lighting turns a simple fault into a big expense!

 

[mattylad]

I am wondering what sort of camera you got that does not have an internal rechargeable battery that enables it to last the required 5 mins?

Even the cheap crappy car DVR\cameras have that ability.

 

[bernardgreen]

Can-bus has it's place, used in things as simple as vehicle lighting turns a simple fault into a big expense!

Failed electronics in steering lock at 5 in the evening., Can-Bus linked to engine management system. Could not start the car, had to be recovered by Green Flag and next day repair at main dealer.

before can bus... remove the steering lock, if necessary join a couple of wires to tell engine management that the steering is un-locked. Drive home carefully.

Some times Can-Bus earns the name Can't-Bus

 

[ban-all-sheds]

I am wondering what sort of camera you got that does not have an internal rechargeable battery that enables it to last the required 5 mins?

And I'm wondering why he wants it to continue recording for a few minutes after he turns the ignition off.

 

[bernardgreen]

It may be for recording what happens in an accident involving the vehicle. It seems they are used in a lot of Russian cars to prove the driver was not responsible for the accident. ( if he or she was responsible the camera tends to dis-appear before the police arrive )