Question for those auto electrically minded

[CraigE]

OK after months I think I have tracked down my elusive power drain. It appears to be coming from the power to my additional fuse box.
The issue I have is I have removed all the fuses and no drop in amperage. The drain appears to be taking around 2.4amps. Way too high and obviously draining my aux battery. Now when I take the main feed + wire off from the battery it drops to zero, so there has to be an issue here.
The set up I have is + and - wires to fuse box are from screw poles on an optima blue top. Heavy duty cable used. Fuse box is a Blue Seas 12 blade.
What else could cause this as I would have thought removing fuses would have found the culprit, but no.
Could it be an earth problem?
Cheers
Craig

[captainslow]

2.4A is a lot of current to just disappear. I'm surprised you can't track down the fault by following the smoke :o
It won't be an earth problem if you're still getting that amount of current draw. I assume you are measuring current draw in series with the +ve feed from the battery. If you've removed all the fuses and you're still getting current draw of 2.4A then you have to start blaming the Blue Seas fuse block for the problem - it really is the only thing that can be consuming, but I would expect the fuse block to get pretty hot. If it's not then I'd be checking the accuracy of the current meter.




Just as a mater of interest, how are you isolating the AUX battery from the cranking battery? Are you sure that these are disconnected.






Cheers
Pete

[CraigE]

2.4A is a lot of current to just disappear. I'm surprised you can't track down the fault by following the smoke :o
It won't be an earth problem if you're still getting that amount of current draw. I assume you are measuring current draw in series with the +ve feed from the battery. If you've removed all the fuses and you're still getting current draw of 2.4A then you have to start blaming the Blue Seas fuse block for the problem - it really is the only thing that can be consuming, but I would expect the fuse block to get pretty hot. If it's not then I'd be checking the accuracy of the current meter.




Just as a mater of interest, how are you isolating the AUX battery from the cranking battery? Are you sure that these are disconnected.






Cheers
Pete

Thanks Pete,
I was using the negative cable as advised is much safer than using the positive and wont arc out if inadvertently earthed and will give the same result.
I found that there are several fuses drawing power, had to pull all out and insert one at a time.
I think I have found the issues as I will describe, but will go out and use the positive cable first. The current draw seemed a bit high to me, but this is basically a powered fuse block so certain things can run regardless of ignition on or off. Will be changing some back to ignition sources, but did not want items such as fridge HF radio to be on ignition. I assume what I am doing is right eg if negative cable used for amp check, main earth cable and earth pole for other earths on battery removed and joined together as would normally occur (optima battery with main +- poles and additional +- screw poles ). Would be the same with + end if I use this.
My set up and what I did find was the following:

1: HF Radio 30AMP Drawing Current constantly even though turned off.
2: GPO Rear Seat no current draw nothing plugged into GPO
3: Thermo fan no current draw
4: Thermo fan no current draw
5: Thermo fan no current draw
6: Amplifier Stereo Drawing Current even though turned off.
7: GPO Rear no current draw nothing plugged into GPO
8: GPO Rear no current draw nothing plugged into GPO
9: Elec brake power source Drawing 3 amps
10: GPO under centre console Drawing 3.6 amp with usb plug in but nothing plugged into usb. When USB plug removed no current draw.
11: Anderson Plug for Fridge. When fridge plugged in and turned off Drawing Current 3.6 amps. When cord unplugged from fridge no current draw.
12: Aux battery Voltmeter through switch Drawing current 3.4 amps with switch turned off (voltmeter not reading) I think this was a bit odd as a volt meter should only draw low current.

I know the easy answer is put everything through ignition and may be an option for a few of these items. But is certainly not for the fridge. I also dont want to put too much load through the existing ignition power eg the HF Radio needs 30amp heavy duty fuse.
Will check using positive cable and report back on here. Will also check using another meter. These are not cheap meters either one costing $140 and one well over $200.
Reading on 600a setting on clamp meter using leads.

[Blknight.aus]

Check.the battery on the meter, they read higher as the inter.al battery goes.flat.

You might also find that ~3A is the lowest step that the meter can display on that setting.

I'd start by using a normal meter on the ten amp scale.

[CraigE]

Check.the battery on the meter, they read higher as the inter.al battery goes.flat.

You might also find that ~3A is the lowest step that the meter can display on that setting.

I'd start by using a normal meter on the ten amp scale.

Dave,
You are probably right as I did not expect to see anywhere near that, maybe between 0.4 and 1 amp maybe. I will try using my SANWA meter, but that showed zero which cannot be right either, there would have to be some current draw.
Cheers
Craig

[Blknight.aus]

You might have a corrosion path to earth feoma positive somewhere

[matti4556]

Craig, Are you using a clamp meter to measure d.c. current?
or has the meter got a d.c. Amps mode that uses plug in leads?
You mentioned using leads but I just wanted to check the obvious first.
IMO the clamp method can only indicate a.c. Amperes.
And on a 600A scale the measurement of low currents might be a little illusive - Is there a lower scale you could use?

You also may be seeing a current through the 2 batteries - the optima is just a path back to the main battery if they aren't isolated - I couldn't see where you mentioned an isolator and what type. Captainslow asked the pertinent question.

The circuit needs to be made clear/er before any stray currents can be "guessed". Cheers - Matti

[CraigE]

Craig, Are you using a clamp meter to measure d.c. current?
or has the meter got a d.c. Amps mode that uses plug in leads?
You mentioned using leads but I just wanted to check the obvious first.
IMO the clamp method can only indicate a.c. Amperes.
And on a 600A scale the measurement of low currents might be a little illusive - Is there a lower scale you could use?

You also may be seeing a current through the 2 batteries - the optima is just a path back to the main battery if they aren't isolated - I couldn't see where you mentioned an isolator and what type. Captainslow asked the pertinent question.

The circuit needs to be made clear/er before any stray currents can be "guessed". Cheers - Matti

Matti,
I have 2 meters 1 x Digitech clamp meter that also has leads and a SANWA multi meter.
The digitech is a high voltage unit and 600a is probably giving an incorrect reading however indicates something. The SANWA must be having some issues as it is showing zero and that cannot be correct either. Will replace the inbuilt fuse in it and check again, wrapped fuse so cannot tell if it has blown.
While the digitech may be over reading it would still be where there is a drain from some areas. With the reading when pulling fuses it did drop to zero when certain fuses were removed. May be acceptable limits though.
The issue I have is there must be some sort of drain as it is flattening a fully charged battery in less than a day with an engel running that I used to get 4 - 5 days out of. The battery does appear to be ok.
Dual battery system with a TJM system solenoid and control box. May be possible the solenoid is cactus.

[Kev the Fridgy]

Craig, Are you using a clamp meter to measure d.c. current?
or has the meter got a d.c. Amps mode that uses plug in leads?
You mentioned using leads but I just wanted to check the obvious first.
IMO the clamp method can only indicate a.c. Amperes.


There are clamp meters available for DC, I use mine quite regularly on low current draw applications, it has shown to be quite accurate at low current draw

[Graeme]

The issue I have is there must be some sort of drain as it is flattening a fully charged battery in less than a day with an engel running that I used to get 4 - 5 days out of. The battery does appear to be ok.How are you determining that the battery was fully charged, how old is the battery and does the fridge cut-out regularly?

[CraigE]

There are clamp meters available for DC, I use mine quite regularly on low current draw applications, it has shown to be quite accurate at low current draw

Yeah the Digitech is AC and DC clamp meter.

[CraigE]

How are you determining that the battery was fully charged, how old is the battery and does the fridge cut-out regularly?

I had been charging right up with CTEK chargers and then testing voltage and also running under load and testing around 20 minutes later. The aux battery is an optima blue top and barely 18 months old and not actually used that much.
I am trying to determine if it is the main battery draining it via the dual battery system, parasitic drain or just the fridge draining it.
Had the batteries fully charged and a 27 litre engel drained it in less than 8 hours below the cut out level. I used to get 4-5 days with an 80 litre running.
I may need to get a battery tester, possible the optima has failed I suppose.
Easy to do with a battery with caps and a hydrometer, but not as easy with the sealed battery. At least the AC Delco start battery has an indicator window.
I have found maybe with incorrect readings several drains, wether they are enough to cause the rapid drain not sure.
HF radio has some amperage turned off.
Voltmeter has some even turned off.
Fridge has some turned off but plugged in. Unplugged has none.
Elec brakes have some drain.
GPO has drain when usb plug put into it, rmoved no drain.
The other 6 odd have no power drain at all using same meter.
I would have thought there would be zero power drain on the fridge if plugged in and turned off.
HF maybe a small amount of power to keep memory.
Elec brake should be none, voltmeter should be none.
Cheers
Craig

[Graeme]

Any device whose off switch is not an old-style mechanical switch will consume power whilst "off" because it has to have at least the power circuits active to know when the device is switched back on. The percentage of consumption varies with each device depending on how much of the circut the electronics shuts down, with older(earlier design) devices being worse than more recent ones. Even a USB power socket powers a voltage regulator chip regardless of whether or not a load is connected.

I agree that the battery should be given a proper load test once fully charged as a priority. I had a dual purpose calcium battery that got discharged too low a couple of times and it never regained full capacity even though its voltage indicated it was fully charged. Its still starting a small pump engine more than 5 years later but had become useless for running a car fridge.

[CraigE]

Bought a load tester today as I wanted to test the 2 batteries in the car and have a couple in the shed I want to test.
Both in the car came up fine and in good condition - top rating.
So not the batteries.
I suppose now just leave the fuses out that I have concerns with and see if it holds charge and add them back in one at a time.
Will be double checking everything again.
Cheers
Craig