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Discussion Starter #1
Hi all,
apologies if this has been covered before - I couldn't find it anywhere on here.

I'm planning to run a double-DIN head unit solely from a leisure battery, and naturally would like the reversing camera to come on when I engage reverse.

In the (admittedly rare) situation where I might engage reverse whilst the leisure battery is *not connected* for some reason, that would mean pulling the stereo's reverse camera input up to +12V whilst there is no power applied to the rest of it.

Does anyone have experience of doing this safely, or is it likely to cause any problems/damage? (apart, of course, from the screen not coming on when there's no power!)

There's no mention of it in the installation guide for my stereo (Pioneer AVH-A3100DAB). I can imagine a variety of ways of doing it cleanly, with relays, etc. but was hoping to avoid the faff.

Thanks,
Rob.
 

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Discussion Starter #3
Yes, I suppose I could have a switch, or even the automatic relay gizmo I've seen on here. But one way or another I'm sure I'll end up flattening the starting battery by accident. I'd rather just not give myself the opportunity!
 

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Want Electrics? Go Wildebus!
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Hi all,
apologies if this has been covered before - I couldn't find it anywhere on here.

I'm planning to run a double-DIN head unit solely from a leisure battery, and naturally would like the reversing camera to come on when I engage reverse.

In the (admittedly rare) situation where I might engage reverse whilst the leisure battery is *not connected* for some reason, that would mean pulling the stereo's reverse camera input up to +12V whilst there is no power applied to the rest of it.

Does anyone have experience of doing this safely, or is it likely to cause any problems/damage? (apart, of course, from the screen not coming on when there's no power!)

There's no mention of it in the installation guide for my stereo (Pioneer AVH-A3100DAB). I can imagine a variety of ways of doing it cleanly, with relays, etc. but was hoping to avoid the faff.

Thanks,
Rob.
As per your last but one sentence ...no screen on when head unit has no power so why would you want to mess around trying to power the reversing camera in that scenario?
Clearly I am missing something here!
 

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Discussion Starter #5
For example, if I drive the van around with a flat, or disconnected leisure battery. It *could* happen, and it'd be a shame to write off £200+ worth of stereo by accident. Hence the question is hopefully not such a daft one! :)
 

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Discussion Starter #6
So, in case anyone ever has the same issue, I have an answer: it's OK to connect the reverse signal line when nothing else is powered.

Some other useful observations:
the red wire carries almost no current - just a few mA to signal to the radio to turn on
the yellow wire carries the whole supply current when on, several amps. This is what I propose to connect to the leisure battery.
when the radio is allegedly off, there's still 0.6A on the yellow wire! I wonder what it all does...
when properly off (ie red is 0V), then yellow current drops to 10mA or less.
the red, reverse and parking brake inputs are all high impedance (~5kohm)


HTH
Rob.
 
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