Where to tap into 10V in the boot?

541 Views 7 Replies 3 Participants Last post by SPlatten, Jan 13, 2021

SPlatten

Discussion Starter · Jan 12, 2021

I have an Audi A5 2012 Sportback 2.0 TDI, I need to tap into at least 10V to power a device that will be situated in the boot. I will already be sniffing the CAN Bus network in the boot. Is there somewhere located near the CANH and CANL wires?

Thank you,

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savs

· #2 · Jan 12, 2021

SPlatten said:
I have an Audi A5 2012 Sportback 2.0 TDI, I need to tap into at least 10V to power a device that will be situated in the boot. I will already be sniffing the CAN Bus network in the boot. Is there somewhere located near the CANH and CANL wires?

Thank you,

Have you managed to find a wiring diagram? Not sure if fuses are located in boot?

To clarify though:
When you say "at least 10V" do you mean the device has a voltage range (10-14V for example?)
Can it be powered by 12V? In which case - splice into the 12V supply in boot (cig lighter)
And importantly - what is max current of the device? Need to check max current on line you've be attaching too or you'll blow fuses.

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savs

· #4 · Jan 13, 2021

SPlatten said:
The actual device has an requirement of 10 to 50 v. This is the device I'm looking to use:

CAN Bus Contactless Reader (CAN-CROC) | From Co-Star

CAN-BUS contactless reader allows safe reading of vehicle data.

www.co-star.co.uk

Blimey interesting! Every day a school day. Very MI5 to latch onto a cable signal path and "listen" to data communicated but without actually tapping physically onto the wire.
Whilst CAN data will be transmitted in 1s and 0s, i can only presume the contactless reader is measuring the current when a data burst is v+ (minimal current but enough to let the reader know what the can message is - and its current vs time (example 1mA for 3 secs, then 0mA for 2secs, then 1mA for 1sec could translate as 111001). Not sure what type of current clamp reader though (Hall, Rogowski). Add a bit of signal processing and hey presto - current clamp becomes a signal decoder!

I couldn't open the data sheet but if you say Voltage operating range of 10-50V then i'm sure splicing into the 12 Cig lighter in the boot should be fine. Have enough wire to ensure device reaches canbus cable. You may have to add more wire to the wire already on the device to reach canbus - which will be fine. Just make sure its insulated fine (no bare wires touching metal work!!)

I'll be interested to see the data coming back!

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savs

· #5 · Jan 13, 2021

Ok. There's some clever people on here!!

CAN BUS speed

100Kbaud I believe, but still start at 500kbaud.

www.a5oc.com

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CAN Bus Contactless Reader (CAN-CROC) | From Co-Star

CAN BUS speed

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