dealing with the option of using the voltage drop across a fuse, aren't the numbers all getting a bit small?
I am asking here, not telling
But for example:
A fuse resistance of 0.011 ohm, surely that would be easily altered, by temperature, the coating used on the fuse blades, even grease deposited from the fingers? You would literally have to measure the fuse in question first, to be sure it was true to spec.
But then you come down to a voltage drop of 100micro volts, would that not get lost in noise in the signal?
I've recently been having a fault with the vectra, which I had been living with for some time already. If I didn't use it for say 10 days, the battery would be virtually flat (70Ah Varta - bought new - less than 12 months old). Even after say 5 days it was quite affected, locks would be slow when unlocking, engine would turn over slower than usual, and a fault with the HID lights would come up on dash - I have found them to be very voltage sensitive.
Anyway, I managed to resolve the drain down to a permanent drain of approx 180mA, of which 25mA was attributable to the various systems requiring memory - ECU, radio, instruments & clock etc. - and to the alarm.
All acheived with the 60amp clamp on 20A setting.
The remainder turned out to be the power windows, amazingly they require all that current just to remember the glass stop positions.
The point being anyway, that in this case the 60A clamp was a success. By making sure to zero it in the same plane, as that in which the measurment was to be taken (an invaluable piece of info I have read on this forum) I had good results.
With relays added into the window power feeds (from fusebox) the car can now be left for weeks on end, and no longer do I have problems with HID warnings.
EDIT: Forgot to mention there, that while watching the waveforms it was easy to spot the increased drain everytime the alarm LED flicked on, as it does every second. ie. On for a second, off for a second. It's a tiny LED. Will have to post the waveform up.