matgriff wrote:

Quote:

Just quickly , u want ur multimeter set to DC amps not volts , then use ur meter probes across the fuses

Ref multimeter in-line for some reason I couldn’t get it to work like that

If you put your meter on the current range (Amps) and put it across a fuse that isn't blown, you'll measure nothing.. the current will flow through the fuse and not through the parallel meter. If you were to put the meter across a blown fuse, (with the fuse body still in situ) then you are in effect completing the circuit with the meter and you'll measure the current drawn by the circuit...but beware, you now have no fuse, so any fault current will blow the meter fuse or meter .

By the way, I'm not trying to be a tw**t here, or a smart ass... I'm just trying to help, I'm a power electronics design engineer, this is the type of stuff I do every day I'd like to pay back some of the help & advice I've got from others on the forum

  

Trucks wrote:

I forgot to ask how could I test the cartridge fuses I believe the plastic top comes off but mine seem to attached to get the cover off(when testing I mean with the meter I can obviously see if they are blow or not lol.))

  

Trucks wrote:

and the car double locked (two presses of the fob)

I thought on a D3 two presses on the fob disabled the alarm/interior sensors. It's 'double locked' with one press. The D4 is two presses to double lock.





Not sure if that would make much difference to your tests though.

matgriff wrote:

Hi again

These type of problems can be notoriously difficult to track down, however some "basic" fault finding techniques can make inroads to pointing you in the right direction.

I appreciate the science behind, for example the table showing the fuses and the voltage drop across each one etc, but my point was (and is) the differences and measurements needed to discern any real information from these is beyond the accuracy of general measurement kit.. for example trying to measure the difference between 0.1mv and 0.3mv dropped across a fuse with a multi-meter of +-2% accuracy on its full range of 1000v is in the wind so to speak.

Of course the reasoning that a larger fuse has a lower resistance than a small fuse is sound, and therefore will have a lower voltage drop for a given current is also sound... that's just ohms law.

Basically if your good battery is draining in 2 days, your looking for a fairly significant problem that can easily be measured with basic test equipment, which you have.

If we go back to your original post, your clamp meter seems to be showing 0.55A, which is 550ma... this is a hefty draw if that's with everything off.

Just taking an example here & remember there are more factors to consider, but in principal if your battery is rated at 75A/hr it can supply 75A continuous for 1 hour or 1A continuous for 75 hours.

Taking your draw of 550ma (or 0.55A) that would give a battery life of 75hrs * 0.55 ie 41.25hours or just less than 2 days, of course the battery would appear "flat" much sooner than that.

So as a starting point, I would look at your theory of different battery life with different locking/unlocking situations to establish some facts.

Extend the cable with a big loop, so that you can fit the meter(s) outside the car with the bonnet closed.

Go through each scenario and measure the parasitic battery drain for each case over an extended period. When you have these results, report back and we can take it from there.

Regards

Mat

Hi mat

If I may say some extremely sound advice

When I had the parasitic drain in mine the meter would sometimes wander , ref the fluke I have calibrated by a mate every year or two because I’m no longer working on boilers I didn’t really need to get them calibrated but do like to at least ensure I can rely on that one

Got and for some reason srill do get so confused when reading the figures , ie where the decimal limit was and know I had to keep asking

Started with 0.85 Ma then after 30 mins dropped to 0.40 which I think is 850ma and 400ma , then when I connected my hantek clamp meter I got even more confused , where It had 1mv to 100ma, I think , lol

Was handy in one sense when I use to diagnose boilers Etc or how to take ur time and do testing in a set orderly pattern, found having a book very handy as a reference point of what I had and haven't tested

For the future would like to get an oscilloscope seeing u can do a lot with them in a wider testing point of view including learning more seeing vehicles will only get more complicated over time and would at least like to try and better understand how the systems work

Thks again if I may say for the excellent advice plus the expertise u have in this subject

Click image to enlarge

  

Trucks wrote:

Jmack
yes that's correct that's as I am sure I said if I use the one press the alarm goes of every 20 minutes or so.
Hence the reason I need to do as suggested try and sort out the alarm problem first,but where do I start looking at that issue? Probably the interior sensors and wiring I guess.
Thanks
Pete

Hi Pete

Nothing like a few faults at the same time thrown in, lol I would link out the bonnet switch first and then lock u disco and see if the alarm goes off

At least then u can systematically go through the system but would start with the bonnet catch

Also know when I issues with the battery draining etc there were so many here who would always spend the time helping me in what to test and why

Fingers crossed it’s just that bonnet catch

Plse let us know how things go