Other Alternator test/ AC

sierrafery said:

Hi, i dont understand your plan and seems overcomplicated, i dont get what you mean by "using another multimeter on each fuse one by one to look which circuit is causing the issues", it's enough to use a multimeter connected in series between the battery clamp and terminal(or a clamp meter on the positive lead) then when the systems went to sleep remove fusible links one by one(i mean remove, see the drop then put it back) ... if there will be a serious drop one one of the FLs at least you'll have to remove only the fuses which are on that circuit not all cos most fuses are somehow connected to the fusible links or of there' is no serious drop on FLs you'll have to remove the fuses which are not through a FL if you see what i mean, when you find it you have to check the power distribution diagram and there you are

btw how much is your battery drain with systems at sleep?

Click to expand...

Many thks

Apologises my bad way of explaining things , lol

Having one multimeter connected to a clamp meter as per the one above , so it shows me what my parasitic drain reading is , putting the clamp around my battery lead

Then using another multimeter to do the actual test on each fuse in the fuse box individually

If I pull a fuse out it will wake the system up and will have to wait another 30 x mins each time for the system to re enter sleep mode

But understand where ur coming from ref the FL fuses and indeed maybe as u say I’m just over complicating things

Maybe just use the one meter and test each fuse individually and make it easier

There’s going to be roughly 100 plus x fuses in the system

Put some pictures up of what my current draw is after the vehicle has gone to sleep and chart if what it should be

I’ve read that as a 40 M amp parasitic drain and should be below 22

Hopefully that makes sense and many thks as always

gstuart said:

If I pull a fuse out it will wake the system up and will have to wait another 30 x mins ....Maybe just use the one meter and test each fuse individually and make it easier....

Click to expand...

Maybe i have a dumb moment but how would you use a multimeter on a fuse without removing it ?

sierrafery said:

Maybe i have a dumb moment but how would you use a multimeter on a fuse without removing it ?

Click to expand...

Lol, As there spade fuses I use the test points on the top of them

gstuart said:

Lol, As there spade fuses I use the test points on the top of them

Click to expand...

but how do you measure current this way cos as long as the fuse it's in place the circuit is closed through it, if you put an A-meter across the fuse you'll see 0 A

sierrafery said:

but how do you measure current this way cos as long as the fuse it's in place the circuit is closed through it, if you put an A-meter across the fuse you'll see 0 A

Click to expand...

Am indeed hoping to see zero across the fuse

I set the multimeter meter to DC and measure across the fuse to try and identify which one is causing the parasitic drain

These are the meters I’ve got

gstuart said:

I set the multimeter meter to DC volts and measure across the fuse to try and identify which one is causing the parasitic drain

Click to expand...

It must be something i miss here though , what ever setting you have on the multimeter putting the probes across the fuse will show you 0, it's like you put the probes together

sierrafery said:

It must be something i miss here though , what ever setting you have on the multimeter putting the probes across the fuse will show you 0, it's like you put the probes together

Click to expand...

Believe me it isn’t u mate as I know ur extremely knowledgeable

Managed to find a video which hopefully will explain better than me what I’m trying to achieve

I must admit that i didnt know that and i've learned something today... with my old school methods would have never crossed my mind to check mV across a closed circuit ... nice find, go for it, though i dont see the usefulness of the clamp meter this way.

@gstuart
Gary, the only way that you'll ever get a reading, current or volts across a fuse is if it's open circuit or blown in layman's language.
The resistance of a fuse is so small so that there will be hardly any measurable voltage drop across it and trying to measure current will be the same as trying to measure current with short circuit meter leads. If you do measure a small value of volts, in the millivolts range then you're still going to have to know the resistance of the fuse to calculate the current flowing through it.
If you use a blown fuse just as a connector to fit in the fuseholder then you should be able to measure volts and current.

sierrafery said:

I must admit that i didnt know that and i've learned something today... with my old school methods would have never crossed my mind to check mV across a closed circuit ... nice find, go for it, though i dont see the usefulness of the clamp meter this way.

Click to expand...

Pleased the video made more sense than me, lol

Clamp meter on the battery lead would at first show me what the parasitic drain was in the beginning

The voltage drop charts mentioned in the video above can be found at:-

https://www.powerprobe.com/fuse-voltage-drop-charts/

brian47 said:

@gstuart
Gary, the only way that you'll ever get a reading, current or volts across a fuse is if it's open circuit or blown in layman's language.
The resistance of a fuse is so small so that there will be hardly any measurable voltage drop across it and trying to measure current will be the same as trying to measure current with short circuit meter leads. If you do measure a small value of volts, in the millivolts range then you're still going to have to know the resistance of the fuse to calculate the current flowing through it.
If you use a blown fuse just as a connector to fit in the fuseholder then you should be able to measure volts and current.

Click to expand...

Hi

Many thks,

Now I’m even more confused and going to tie myself up in knots here , plse bear with me, lol

Is this the kind of chart below u mean plse

So if I’m reading it right , it won’t be just one fuse but multiple in order to make up the 40 Mv that is causing the parasitic drain when the vehicle is asleep

What I don’t understand is how the system is able to continue to drain the battery with the vehicle off, unless maybe something like a radio keeps pulling voltage

Alternator and battery is ok

Don’t mind admitting can get to a certain level of electronics and then goes over my head

Thks again as always for the great help

brian47 said:

The voltage drop charts mentioned in the video above can be found at:-

https://www.powerprobe.com/fuse-voltage-drop-charts/

Click to expand...

Many thks, I wondered where they all were , mine are the mini spade fuses

gstuart said:

Hi

Many thks,

Now I’m even more confused and going to tie myself up in knots here , plse bear with me, lol

Is this the kind of chart below u mean plse

So if I’m reading it right , it won’t be just one fuse but multiple in order to make up the 40 Mv that is causing the parasitic drain when the vehicle is asleep

What I don’t understand is how the system is able to continue to drain the battery with the vehicle off, unless maybe something like a radio keeps pulling voltage

Alternator and battery is ok

Don’t mind admitting can get to a certain level of electronics and then goes over my head

Thks again as always for the great help

Click to expand...

Forgive me, but I've come to this fred a bit late.

Where are you getting this reading of 40 mV?
From what I've seen, you look like you're trying to measure something with a clamp meter.
So, where can the current (not voltage) be going when the vehicle is switched off? The first thing to stop as the video showed is to make sure that the doors, bonnet and boot are closed. Then turn the vehicle off and leave it go to sleep.
But it won't be asleep completely, you still have the security system, and then what you're dreading, a possible fault.
A parasitic drain will always be a current, measured in milliAmps or (perish the thought) Amps.
What the video was doing was using the inherent resistance of a fuse to show a small voltage drop across it which by using the appropriate calibration chart can indicate the amount of current being drawn through it.
That Mister Ohm bloke strikes again.

Brian, the clamp was on the positive lead which is OK

Stuart, MO better not eat your mind so much cos even if the quiescent draw table shows <22mA if you have 40mA it means it's only 18mA more than normal and that table is for bran new vehicles... a 40mA drain can't be considered a problem whatsoever, the vehicle's harnesses which are in the engine bay are all suffering from heat and theyr's resistance can grow a bit in time also there can be dust deposits in the plugs and fusebox which can absorb moisture, etc all these things together can affect the quiescent drain.

a 40mA drain means that a 100AH battery will drop to 70% of it's capacity(it will still crank without probs) and that's about 800 hours(33 days) while with the ''normal" up to 22mA the battery would drop to around 80% in 33 days as well

Here's something to put your mind to rest and not worry so much: https://www.optimabatteries.com/en-us/experience/2010/12/what-normal-parasitic-draw also don't rely 100% on that quiescent draw table cos as i see it shows the D2's shut down period to be 30 minutes which is false cos in reality the SLABS goes to sleep after 90 minutes on those with SLS ... eventually measure your drain after let's say 2 hours, maybe you'll have a surprise

brian47 said:

Forgive me, but I've come to this fred a bit late.

Where are you getting this reading of 40 mV?
From what I've seen, you look like you're trying to measure something with a clamp meter.
So, where can the current (not voltage) be going when the vehicle is switched off? The first thing to stop as the video showed is to make sure that the doors, bonnet and boot are closed. Then turn the vehicle off and leave it go to sleep.
But it won't be asleep completely, you still have the security system, and then what you're dreading, a possible fault.
A parasitic drain will always be a current, measured in milliAmps or (perish the thought) Amps.
What the video was doing was using the inherent resistance of a fuse to show a small voltage drop across it which by using the appropriate calibration chart can indicate the amount of current being drawn through it.
That Mister Ohm bloke strikes again.

Click to expand...

Hi

Don’t be daft always happy for any help

Indeed that’s what I done, linked the bonnet catch out, locked and alarmed then waited 30 x minutes

Have had the alternator and batteries all tested , yet max before the main battery goes flat as in not being able to crank the engine is 12 x days

Main Is an exide 100 amp , 900 CCA , other is a leisure battery , as my intention was that’s for when I go camping of protecting the main battery going flat

Have read a lot of the months and indeed heard where infotainment systems can cause a lot of drain mine doesn’t have all the extra toys

In further investigation I’ve found fuses that I don’t need , as I haven’t got the items fitted

They are

F5 petrol EMS

F7 front seat HEVAC

F8 Rear heated seats

F15 Front heated screen
F18 Front heated screen

F22 Rear blower

So will remove these first and then start from scratch , so I haven’t missed anything

As always many thks

sierrafery said:

Brian, the clamp was on the positive lead which is OK

Stuart, MO better not eat your mind so much cos even if the quiescent draw table shows <22mA if you have 40mA it means it's only 18mA more than normal and that table is for bran new vehicles... a 40mA drain can't be considered a problem whatsoever, the vehicle's harnesses which are in the engine bay are all suffering from heat and theyr's resistance can grow a bit in time also there can be dust deposits in the plugs and fusebox which can absorb moisture, etc all these things together can affect the quiescent drain.

a 40mA drain means that a 100AH battery will drop to 70% of it's capacity(it will still crank without probs) and that's about 800 hours(33 days) while with the ''normal" up to 22mA the battery would drop to around 80% in 33 days as well

Click to expand...

Many thks and appreciate all this help

My main battery won’t go past 12 x days before it’s unable to crank the engine , was the same with the old battery

Indeed looking at the chart mine should be no more than 22 , also shows my relevant year 2005

Something is obviously causing it to drain and of course finding out why

Have since found some extra fuses fitted that I don’t need , so will remove them

Here goes a theory , please don’t throw anything at me, lol

As items aren’t fitted in mine like a heated seats, heated screen etc, it still has the looms but connectors on the end are empty because the items arnt attached

Can having those long lengths of looms cause a drain because a relevant item, ECU isn’t fitted ????

So therefore pulling the fuses should in theory kill any power going to those items

I’ll get my coat , lol

sierrafery said:

Here's something to put your mind to rest and not worry so much: https://www.optimabatteries.com/en-us/experience/2010/12/what-normal-parasitic-draw also don't rely 100% on that quiescent draw table cos as i see it shows the D2's shut down period to be 30 minutes which is false cos in reality the SLABS goes to sleep after 90 minutes on those with SLS ... eventually measure your drain after let's say 2 hours, maybe you'll have a surprise

Click to expand...

Many thks, will have a read

Also know mine wakes up every 6 x hours to self level

Good idea and will check it at different intervals

Do charge mine through the 12s trailor socket , wonder if I could get an accurate reading , because I could run an extension lead off it to indoors and then put a multimeter in the end and check it over s period of time

Believe an oscilloscope can take readings and record it over a time period

Thks again