Legacy power source when key off

[aaronpnz]

hi all, as part of my in-dash tablet install, I'm wondering if there is any power source that is only alive when the car is turned off. So, that when I turn the car off and leave it, this source becomes alive at that point, and then stops when car is turned back on. 

 

I'm having problems keeping the N7 powered up for longer than a few days, and have "stuck" a wireless charger to the back of the tablet, that I want to only charge when the car is off.

 

I had wondered if there was anything that I can use from the immobiliser side of things?

 

Either that or a relay switch that connects power on key off.

 

Anyone got any clues here?

 

Cheers,

 

Aaron 

[Joker]

Majority of 'Positive' feeds become negative when the car is off

 

which you could use if you tap onto an 'aways' on +

 

then the - side to a "+" when "on" feed

 

now this is useful for Diodes that only allow current flow in one direction so a little extra elec-trickery might be need to 'keep the smoke in' but the theory is there if you catch my drift (or a Relay)

 

so yeah basics are there BUT not tested on equipment in real life so no guarantees or warranties implied with this post

[Andy_Mac]

What exactly is your aim here? Do you want it to fully charge while the car is off and then not charge when on?

 

Before you go down this route there should be a simpler way to resolve this. I only use mine on weekends and it’ll typically use 1/2-2/3rds of the charge throughout the week sitting there. Car lives outside too so the heat plays a big factor in this. 

 

Have you flashed the timur rom and all that to it? If so what is your charging rate in power event manager?

 

If you have to go down this alternative route then a relay off a non switched source with a switched source on the coil is your best bet if charging when car’s off and not when car’s on is your goal.

[HannesNel]

You also need to be mindful of how much your car is going to stand and be used. You dont want to get into the car one morning with a dead car battery as the tablet used all the juice. They draw very little current but for prolonged periods of time consider having a hard cut switch wired in (or just pull the fuse if you have one) 

[pl0x]

Sounds like a recipe for flat battery's but:

 

Constant power wire to the radio, pretty sure it's the yellow one. Along with Andy_Mac's relay wiring to switch it off when the car is on.

[Dre]

I had a cell phone hooked up to the alarm in my old bh Legacy.Over winter would drain battery if not driven for 7-10 days.

[aaronpnz]

Thanks all, love the support. 

 

Yep, I'm running Timurs kernel on Remix 7.1.2 and charging varies but is 695mA right now. 

 

Car sits all day at work and overnight with a 20 min drive to and from work, so not long to charge. The idea is to trickle charge using wireless pad when sitting not on. 

 

I've tried Tasker to shut things down on AC power off but Tasker seems to "get lost" at times. 

 

Generally I'm very happy with the setup, running Android Auto via Headunit Reloaded over USB or wifi direct works great. 

 

It just goes flat too fast.