Head unit is draining my battery out
Discussion
Back in the summer I installed a head unit for the first time and recently I had a flat battery. Old battery fair enough I thought, so I replaced it. Park up for two days, and cranking seemed very laboured. Check of the multimeter and I'm barely at 12v. Bummer, what a waste of money.
Anyway, I've established it's the head unit that's drawing the current even when the vehicle is off and locked. Measured the current before and after pulling the fuse (0.8A vs 0.14) Bingo, great. Now the hard part, actually fixing it.
On my head unit ignition live (red wire) is connected to an ignition only source. So, when I turn the key, the radio turns on. The head unit is also connected to a constant live (yellow wire) and this is via a 10 amp fuse on the main fuseboard. When I turn my vehicle off and pull out the key it goes to 'standby', When I pull the constant live fuse out, it only turns on when the ignition is running so all wired properly it seems?
I have tried a bunch of different fuses to tap the constant live with on the fuse board but when I check the power draw I can see that 0.8A load every time.
Help!
Anyway, I've established it's the head unit that's drawing the current even when the vehicle is off and locked. Measured the current before and after pulling the fuse (0.8A vs 0.14) Bingo, great. Now the hard part, actually fixing it.
On my head unit ignition live (red wire) is connected to an ignition only source. So, when I turn the key, the radio turns on. The head unit is also connected to a constant live (yellow wire) and this is via a 10 amp fuse on the main fuseboard. When I turn my vehicle off and pull out the key it goes to 'standby', When I pull the constant live fuse out, it only turns on when the ignition is running so all wired properly it seems?
I have tried a bunch of different fuses to tap the constant live with on the fuse board but when I check the power draw I can see that 0.8A load every time.
Help!
David Beer said:
The permanent supply is for the output stage as well as memory. Do you have any type of steering wheel interface, aerial amp trigger etc ?
What car and what is the head unit ?
Most modern unit will be well below 3 ma on the permanent supply.
Yes! I have a Connects2 CTSNS001.2 interface adapter for the steering controls of my Nissan NV200. I emailed Connect2's tech support and they mentioned that the adapter is analogue only so shouldn't cause an issue. I'm not too sure.What car and what is the head unit ?
Most modern unit will be well below 3 ma on the permanent supply.
Head unit is an Atoto S8.
Unfortunately I blew my last and only 10 A fuse on the constant lead. Bummer. More on order...
In the meantime I checked that my permanent and switched lives were working as they should and not reversed. No problem. I then grounded my constant lead to the chassis blowing my fuse. Idiot. Was going to load test it.
The earth ring was wedged between a piece of metal and plastic. It held tight but wasn't 'fixed' as such. If that's even slightly loose would that really explain the high draw?
David Beer said:
The earth/ neg can not increase the draw, it will earth through the aerial anyway.
I would remove the interface completely and retest.
No amps fitted or anything else ?
Nope, the head unit has an internal amp though. I'll try and take out the controls interface and see what happens. Otherwise I'm miffed and will begrudgingly have to drag it off to an auto electrician (who will probably tell me the head unit is naff!)I would remove the interface completely and retest.
No amps fitted or anything else ?
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