I'm designing a hidden camera system for the cab of my '05 f150. It'll be triggered via a relay on the ACC wire to turn on only when the truck is off. It has a motion detector and will only record when someone's in the truck.

It consumes approx 300mah at 5v. How long do you think I could leave the truck off and it on before I'll have starting issues?

 

The other question is how much power is the voltage conversion going to use.

What you are using to convert the 12 V to 5V is going to use power as well ( some are very inefficient ), and you could go from 0.3 ah to 1.0 + ah usage depending on the product.

 

I was planning on cannibalizing an old cell phone charger that provides 5v at up to 850mah. It seems like many electronic devices run on 5v dc. The plug I was going to use doesn't get warm so I don't think it's wasting power. I've been googling and can't seem to find anything about the consumption of most adapter/voltage regulators, only the out put power of various models.

Any guess as to the waste in the conversion? Maybe 100mah??? (complete guess)

 

Hello.

Just rambling out loud here, but don't you mean ma (not mah)?

Anyway - normal quiescent draw is in the 50ma range, and that will not discharge the battery for several days. If you scale this by a factor of 6, you could probably still go a good while (depending on ambient temps, battery type/age/condition, etc). Overnite for example. But not for very long periods. Pehaps up to a week, but that's pushing it. Here's a good thread on this: https://www.f150online.com/forums/el...elp-600ma.html


However, might I offer a small design change? Why not trigger your device via a pulse ( or edge trigger) from the door switches (unless you figure folks are gonna break the windows and crawl in without opening a door, lol).

If you build a one-shot monostable using Cmos or low-power 555's it will draw onlymicroamps while monitoring the door switches (and a glass breakage sensor optionally). Upon trigger, this in turn can be used to energize a small relay to activate yer device. You can determine the turn-off delay, or get fancy and turn off at the next door switch edge.

Just a thought - lots of possibilitiies.

W.R.T power supplies - if you use a good switching regulaor the efficiency is high ; ~80%.

Good luck.

MGD

 

...perhaps.

Thanks for the info. I've been considering using a relay off the dome light or similar but I'm not sure about the boot up time of the DVR until I get it and start screwing around with it. If it boots up quickly, that would certainly solve the battery life issue.

I'm adding an alarm as well so perhaps I could use a relay off an output on the alarm, again provided the DVR boots fast enough.

Thanks for the info. I have just enough knowledge of electrical stuff to be dangerous so any input from you guys is quite welcome and appreciated.

 

There are battery monitors that turn off the accessories when the battery dips to 10.5 volts or so. Plug one of those in and forget about it. here is a typical unit. http://www.powerstream.com/battery-protector.htm

.

 

Nice, JMC

Although, you may want to use one of the higher voltage cutoffs - 10.5 v = DEAD battery





MGD