Parasitic Drain --

Parasitic Drain BMW E46 --- 400ma :ohmy: I did volts drop testing on the engine bay blade fuses and fuse links and found nothing. Then pulled all the blade fuses and relays in the engine bay box and measure current directly nothing stood out although one fuse had some corosion so I replaced that.
I then moved to the passenger compart fuse box --- Owon B35T Meter measuring curent on main battery earth cable linked by Bluetooth to my the phone I pulled all the fuses no change.

Back to the engine bay fuse box , I switched to using my Clamp meter (Uni-T UT203) on the main battery cable to measure the current same 400ma reading. At this point I noticed that one of the Maxi fuses was loose and the fuse box was damp, so I removed and cleaned the fuse, sprayed everything with Duck Oil and tightented every screw in sight.

Then watched and waited the current as the system shutdown success ! I suspect that the loose fuse was stopping one of modules going into full hibernation mode.

Andy.MacFadyen wrote: Parasitic Drain BMW E46 --- 400ma :ohmy: I did volts drop testing on the engine bay blade fuses and fuse links and found nothing. Then pulled all the blade fuses and relays in the engine bay box and measure current directly nothing stood out although one fuse had some corosion so I replaced that.

Does this (could this) "wake up" modules, like pulling the fuse and stuffing it right back in instead of leaving it will do sometimes?

Andy.MacFadyen wrote: I then moved to the passenger compart fuse box --- Owon B35T Meter measuring curent on main battery earth cable linked by Bluetooth to my the phone I pulled all the fuses no change.

That's exactly the scenario I envisioned for that meter! I haven't had the chance to try it for that yet.

Andy.MacFadyen wrote: Back to the engine bay fuse box , I switched to using my Clamp meter (Uni-T UT203) on the main battery cable to measure the current same 400ma reading. At this point I noticed that one of the Maxi fuses was loose and the fuse box was damp, so I removed and cleaned the fuse, sprayed everything with Duck Oil and tightented every screw in sight.

Duck Oil?:blink:

Andy.MacFadyen wrote: Then watched and waited the current as the system shutdown success ! I suspect that the loose fuse was stopping one of modules going into full hibernation mode.

Pretty cool stuff man. Thanks!

Duck oil is a WD40 style product popular in the UK
Owon bluetooth feature was handy, bigest problem was getting a reliable connection to the battery cables, but the real surprise was the UNI-T clamp meter was useable at low currents.
I have seen good YouTube reviews of a reasonably priced DC low range clamp meter the CEM DT-377 and I am really tempted. to buy one if I can find a European supplier who isn't charging twice the cost buying from a Chinese eBay shop.

That was the other thing, I've had little success measuring parasitic drain with my amp clamp, but that seems to be how a lot of techs are tackling key off drain problems.

I ran up this table to estimate the days parked up before a non-start due to a given parasitic drain. The figures are very much on the pessimistic side.

I've been using a clamp meter to help with parasitic draw. This is the one I have.
www.amazon.com/ESI-687-Amps-Current-Prob...pecialties+amp+meter
Overall pretty good. Will eventually be getting one like this.
www.amazon.com/Electronic-Specialties-68...pecialties+amp+meter

or this one
www.amazon.com/685-Amps-Current-Probe-Fr...pecialties+amp+meter

gav09 wrote: I've been using a clamp meter to help with parasitic draw. This is the one I have.
www.amazon.com/ESI-687-Amps-Current-Prob...pecialties+amp+meter
Overall pretty good. Will eventually be getting one like this.
www.amazon.com/Electronic-Specialties-68...pecialties+amp+meter

or this one
www.amazon.com/685-Amps-Current-Probe-Fr...pecialties+amp+meter

I've seen that style in stores, but assumed they wouldn't be great for what we do.
I may have to reevaluate my position on that one

My favorite way of identifying which circuit contains a draw is to set my multi-meter to Milli-volts and voltage drop test both test points of a fuse.

If there is no current on the circuit, you will get 0.0 Milli-volts.
If there is any current flow, you will get a voltage drop across the fuse.
I have, somewhere, a table / chart that I will post that calculates the amperage from the amount of drop, depending on the fuse amp rating.

Power Probe has 'Fuse Voltage Drop Charts' which you can download:

info.powerprobe.com/fusechartsdownload