Battery drain....?

[keith]

Hi

Is 0.2 amps ....which i believe to be 200 milliamps excessive when measured from a disconnected earth terminal strap and the earth battery terminal.

Cheers.

[keith]

Fully charged battery last night so it measured 12.8 v this am.

Left the neg terminal diconnected so that i can measure 24 hours later.....ie tomorrow.

[Jeff J]

Some radios are constantly drawing current even when switched off.

[lloydy]

0.2 is high, that's an amp every five hours.. 0.002 is more normal. I had a similar reading and it was the stereo, I now remove the front.
As your tdi, don't forget the ecu will draw a bit of power when you reconnect the power. You have to wait for it to go back asleep to get a proper reading. Like leave your leads connected for a couple mins, and you may see it drop a bit.

[ghost123uk]

200mA is getting to the high side of acceptable. Mine is around 80mA. Most of it is the radio "memory" chip (for the clock and station tuning etc).
Some radios (Sony are famous for it) consume excessive amounts even when off (god knows why). Alarm systems, trackers, clock, voltmeter, they all add up. You can detect what is doing it by doing the same current tests, but in the feed wires to the radio, alarm etc.

[syncroandy]

200mA seems too high to me also. I'm not that experienced with car audio, but from what I've seen head units sometimes have several 'power' connections, eg. battery, ignition, earth, and 'key inserted' from the ignition switch 'S' contact. It may be these need to be connected 'correctly' for the unit to be fully powered-down.

[keith]

Need to have another probe around then.....thanks for confirming.

That result is with the tracker off.....i think. ( battery backup switched to off)

Sorry Ghost....i dont understand what you mean by feed wires ?

My plan was to connect the multimeter again and then to pull out fuses.

Anyone know which is the radio fuse off hand.....as i will start there.

Cheers for the replies.

[keith]

Didnt know that about the ecu Lloydy....will connect and leave it for a bit longer.

[syncroandy]

The radio, 12v socket, and interior lights are on Fuse S3 (15A). Simplest way to check current draw is by taking out the fuse and putting an ammeter across. The TDI ECU has no battery connection, just ignition.

[keith]

Thanks Andy.

Do i still keep the mm set to 10 dc amps ....same as it was on the battery.

[ghost123uk]

Sorry Ghost....I don't understand what you mean by feed wires ?

As in = undo the main live wire (red) feeding the stereo, connect the meter between the ends of the 2 wires you now have (after undoing the connection) and measure the current flowing (if any). Then do undo the connection for the "memory" wire feeding the stereo (usually yellow) and do the same. Reason is the radio fuse will only be feeding the main input wire (red) and not the memory wire. Doing it this way also increases the accuracy of your measurements and gives a better understanding of what is going on. Do the same trick for any other (normally red) voltage feed wires to stuff like the alarm and the tracker etc.

[keith]

Im with you now Ghost....cheers

Same principal as before....to wire the mm into the flow of the circuit....

Many thanks.

[ghost123uk]

Same principal as before....to wire the mm into the flow of the circuit....

Do i still keep the mm set to 10 dc amps ....same as it was on the battery.

Doesn't really make much difference for these type of measurements, as long as you understand where the decimal place should be
Also, leaving it set to 10 Amps is safer in so much as, if the radio is on, it will draw a current that might blow the meters internal fuse if set to milliamps.
However, be careful not to touch the probes between a live and an earth when set to any current (Amp) setting. Ths is the cause of the demise of 90% of multimeters (fused or not).

[ghost123uk]

Tip = when doing these type of current measurements = connect the black probe to the device being tested (radio etc) first, then touch the red to the supply wire to get your reading. If you do it the other way round, it's all too easy to touch the black probe accidentally onto a bit of earthed metal, causing a short that will either blow the fuse in your meter, or worse, burn the meter out.

[keith]

Cheers