CDT quiescent drain measurement with clamp meter

[MSS]

In another thread a member mentioned the use of a clamp meter for measuring the quiescent current with a clamp meter.

Well, here it is being done earlier today just as a check.

Note the use of a brick to simulate closed bonnet.

https://the75andztclub.co.uk/forum/a...1&d=1632607692

Measurement at time 0 - a few seconds after car being locked with everything switched off

https://the75andztclub.co.uk/forum/a...1&d=1632607830


Measurement at 2 minutes (the drain reaches this value in a number of steps as systems shut down)

https://the75andztclub.co.uk/forum/a...1&d=1632607830


Measurement at 12 minutes

https://the75andztclub.co.uk/forum/a...1&d=1632608005


Measurement at 20 minutes

https://the75andztclub.co.uk/forum/a...1&d=1632608031


The final value is about 25mA.


I would accept up to 50mA but would definitely investigate if the final value was over 75mA


A clamp meter certainly makes taking these measurements rather straightforward. However, the cheap clamp meters are of no use as they only measure AC current. An AC/DC current clamp meter is required and the one being used here is the cheapest decent one of which I am aware. It is available for just over £40 to £50 from various suppliers. It is a UNI-T UT210E.


Some cars have more complex, multi-lead, connections to battery posts e.g. our Vauxhall Twintop. In that case I just use a jump lead to bring out a single lead for the clamp.