Wiring backup/Rearview camera -- can engine crank damage?!

**justintime** · 11-09-2005, 05:24 PM

I have began planning the installation/wiring of my rear-view (backup) camera, and while at it I have come across a couple of uncertainties

I plan to wire the camera (12V DC) directly to one of my reverse white lamps. This way, when I backup my car in reverse, the camera will be powered, and my Xenarc will autoswitch. OK, nothing new here so far, now the question...

My car is a 5-speed manual. I normally engage my vehicle in reverse after parking and shutoff the engine. What this means, is that when I start my engine later, it is normally already engaged in reverse, so I am cranking my engine with clutch down, and gear in reverse...

Under these conditions, I am initially powering the camera while cranking the engine, because the rear lamps are effectively powered while starting the car (gear is in reverse). I assume the voltage will be somewhat below 12V while cranking (need to measure it still) -- can this damage the camera? Also, could the voltage actually go above 12V while or after cranking the engine, and would it damage the camera?

I'm thinking about putting an inline fuse for this, but not sure to what extent this would protect me... surely won't protect me against under-voltage

Thanks for feedback/suggestions.

**justintime** · 11-10-2005, 11:04 PM

Bump. Anyone? Stupid question? has it been answered before? Could not find anything.

Thx

**roadhog** · 11-10-2005, 11:12 PM

I think the biggest potential problem with electronic devices during cranking is that the alternator can produce some nasty spikes. I have had a mobile phone charger fail at this point in proceedings so I think it is possible. Some kind of power smoother would therefore better than fuse, something like an inline choke and capacitor across the supply could do the trick.

**kamikaze2112** · 11-10-2005, 11:14 PM

well, i know that when i crank my car, none of my accessories are on. I think your camera is going to come on for a second, then off while the car is cranking, an then back on again after the engine is running. You might be able to wire in some sort of delay to keep it off til your engine is started, however, it will delay the monitor autoswitching as well.

**justintime** · 11-10-2005, 11:16 PM

SO if I'm reading this right, anything above 12V could potentially damage the camera, but anything below 12V is OK?

Thing is, the camera instructions say that both above and below are problematic. but it doesn't explain any further. Of course.

**roadhog** · 11-10-2005, 11:17 PM

Not sure re the acc cutout, maybe have someone check if the reverse lights cut out during cranking?

**roadhog** · 11-10-2005, 11:20 PM

I can't give you any figures, but I believe the power spikes can be significantly above 12v. The thing is, they have such a short duration (micro seconds) that things like bulbs and so on aren't really affected.

**justintime** · 11-10-2005, 11:20 PM

Originally Posted by roadhog

Not sure re the acc cutout, maybe have someone check if the reverse lights cut out during cranking?

Tried that first! My wife did not notice any interruption in the lights while cranking etc...

**roadhog** · 11-10-2005, 11:24 PM

Originally Posted by justintime

Tried that first! My wife did not notice any interruption in the lights while cranking etc...

Sorry... I often state the obvious

**sYx66** · 11-11-2005, 12:05 AM

I don't see reason why you must put your manual transmission into reverse. Simply re-learn to put it in first gear. The ratios are very close.

Your eq might suffer only if there is over 12V spike. It won't suffer if there is less voltage. Certanly you can get one of the DC-DC power supplies and put that between. They have capacitors that try to keep voltage steady during a crank. I don't it's worth the money though just for a camera?