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-   -   Parasitic Draw Test on a Grand Vitara - Voltage drop of 0.6 to 0.8V (https://www.team-bhp.com/forum/technical-stuff/225435-parasitic-draw-test-grand-vitara-voltage-drop-0-6-0-8v.html)

My 2007 Grand Vitara battery has been showing a voltage drop of 0.6 to 0.8V over a fortnight with the car idle; the issue never reared its head when the car was being driven everyday.

I noticed the problem first sometime in November last year when the battery was just 5 months old, but overlooked the issue as being due to low usage.

The car would always start but this drop in voltage was bugging me.

Charged the battery fully and then decided to perform a parasitic draw test to get to the root of the problem:

1. Opened the bonnet and removed the screw on the driver door stop switch; then locked the car using the remote.

The car was thus tricked into going to sleep even with the driver door open (The Grand Vitara has no bonnet switch connected to the security system).

2. Waited for a few minutes, then disconnected the battery -ve.

Using a multimeter in amps mode (red lead shifted to the DC amps port and selector moved to 10A), connected the red lead of the multimeter to the negative cable, and the black lead to the negative terminal of the battery.

Amps measured was initially 3 then stabilised at 0.09A.

Test was repeated and the amps stabilised at 0.09A and never dropped below this; so that made it a parasitic draw of 90mA, which is approx double of the recommended maximum of 50mA.

3. Connected the battery -ve cable back - the car is still tricked to believe it is locked.

4. Shifted the multimeter red lead back to the volt port, and moved the selector to 200mV.

Checked all fuses in Fuse Box. No.2 in the engine compartment, by placing the multimeter leads on the two small metal dots on top of each fuse - all of them read 0.0 mV.

5. Then moved to Fuse Box No.3 just above the accelerator pedal - this is the worst location for a fuse box.

Checked all fuses - fuse no.44 showed a reading of 0.4-0.5 mV while all others read 0.0 mV.



Repeated the test on all fuses and fuse 44 showed 0.4-0.5mV on all tests; as per a fuse mV - mA chart published by powerprobe, the 0.4mV corresponds to 87mA for a 15A mini fuse which perfectly explains the parasitic draw my car was facing.

Fuse 44 is the dome fuse and has a the Audio, interior lights( roof lamps, courtesy lamps, luggage lamp), MID, Audio, ECU, and BCM linked.



Looked at the circuit diagram and also found one link to the subwoofer - removed the subwoofer relay, but the reading remained 0.4V.





The interior roof lamps and courtesy lamps were never disturbed so had no reason to doubt them.

6. Moved to the luggage lamp and I find a cable that was connected to the luggage lamp 12V supply moving all the way to power the reverse camera.

The cable near the camera was warm, so I disconnected the power to the camera and bingo - fuse 44 showed 0.0 mV.





7. Repeated the test and the reading was 0.4-0.5mV with the camera connected and 0.0 mV with the camera disconnected.

8. Went back to the battery, disconnected the -ve, and the amps draw now stabilised at 0.0 A.

Key Learnings:

I suspected the Kenwood stereo to be the source of parasitic draw but I was proved wrong.

It is a good idea to install switches for aftermarket accessories like sensors and reverse cameras because these are cheap stuff. If I look back, what I got was supposedly hi quality but worked flawlessly without parasitic draw only for 2 years.

I have this feeling that I changed my battery prematurely at 4 years and 3 months in Jun2019 because of this hidden devil:Frustrati

MODS : I found no thread on a Parasitic draw test on the forum and hence have created one.

Thats like Mr Sherlock Holmes investigating his car clap:

What would have been the right wiring for camera to not create this leakage current issue?

^^Good investigation. Liked your systematic approach. My Civic’s one and half year old battery discharged to 5V earlier this week. I suspect a parasitic draw somewhere in the system. Currently I’ve charged the battery and it is on self discharge test. While the self discharge for last two days seems to be normal, I think I’ll have to inspect the car on the same lines.

Thanks for sharing.

Thank You, @Saket77.

I also performed the battery self discharge test for 3 days before embarking on this exercise.

It wasn't easy to do this parasitic draw test, but thanks to youtube and my perseverance, I devised and executed my own method viz. amps test at battery with battery disconnected + mV test across fuses with battery connected.

Mazaa aa gaya !!!

Holmes the meddler is what I am :-)

I need to check what is wrong with the camera cable - it works well, so I'm just thinking if it is because of water ingress over 3 years or something else

Good DIY test procedure @vigsom. Thanks for sharing.

Talking about batteries my cars haven't been started for several months now so I plan to charge the batteries (hope they retain a charge) and then redo the parasitic draw test that I had done about 3 years ago. The drain was about 0.04 A IIRC, it will be interesting to see what shows up now with components and wiring getting on in age. Both batteries are about 3 years 3 months old, this is normally the time I have them load tested to prevent a break down at some inopportune moment. Idle time would have probably resulted in sulphation.

Excellent job!

Why not leave the Multimeter in mA mode, pull the fuses one by one, see if the current drops? Goes very fast.

Jeroen

That would work well too. But in some newer cars putting back a pulled out fuse may ‘wake up’ a computer or a system, putting you in a situation to wait again till the car goes into sleep mode so that the draw stabilises.

Regards.

Why would pulling a fuse wake a system? Even so if you push the fuse back it still provides a new reference. Doesn’t matter at all I would think?

Jeroen

Thank You, Doc @R2D2

Forty mA is within normal limits, Doc.
I've never left a car idle beyond 2 weeks ( happens only if I was out of town), and if in town I'd start up once a week and at least idle for 30 minutes OR drive 10kms.

Thank You, Captain @Jeroen .

I initially thought of that, but found that removing and re-fitting fuses in that awkwardly placed fuse box above the accelerator pedal wasn't a good idea - you'd have seen in what pose I did the test.

Also, I found the mV route much faster.

This car is my darling - throws me a challenge every year.

* 2017 - it was an automatic transmission error and took me 4 days to get to the issue( rats had chewed away some cables)

* 2018 - the brake pedal travel had increased - took 10 months to trace it to a leaking ABS

* 2019 - parasitic draw, which finally got solved in 2020.

The wiring harness, couplers, sheet metal are all still in top notch condition for a 13 year old car - the wiring harness cable gaskets/grommets at the firewall and at the rear towards the tail lamps are designed not to allow water inside.

I have found similar values on many modern cars. Usually that does mean the car has an immobiliser system or similar active. If not it could drop by about half.

Whatever, it worked for you, so excellent job!

Even though in theory easily explained on how to trace a parasitic draw, in practice it can be quite a challenge. That is apart from getting physical access to parts and bits.

Identifying which main circuit tends to be the easy part. But finding the actual problem can be very time consuming and frustrating. You did really well!

If it is like a chaffed wire in some inaccessible spot it can be almost impossible.

I have a small electrical problem in one of my cars. Had it since I bought the car in 2009. I must have easily spend upwards of 50-60 hours trouble shooting over the years. Still havent been able to locate the fault, which I suspect is just a faulty wire/poor ground.

Jeroen

Good job. I have only one question. Was the rear camera an add on or came as standard?. I don't see it being listed as one of the circuits connected to Fuse No 44. I did not check the full forms all the abbreviations.

On a side note, observations from my Honda City were a visibly turned on LED indicator on the OBD2 dongle, and the USB LED ambient lights too would remain on after the engine was switched off.

Those who have the OBD2 always plugged into their port, may not be able to see or realise that it's switched on in their car after the engine is off.

It was an add on as only a handful of cars,e.g Accord, built then, came at best with parking sensors.

I mentioned in my Key Learnings that all aftermarket stuff like this must be fed via switches so that the power can be switched off as required so that devices don't inadvertently sap power.

Maybe if this camera had been powered via the accessory circuit instead of the luggage lamp, this issue wouldn't have occurred and my thread wouldn't have been up:D

If I am not wrong, the first car to come with a factory camera and in mirror display was the i20 Asta sometime in 2011.

Good observation - reinforces not having any unnecessary add ons.

I see the problem now. The electrical guy just extended the 12V from the nearest available point , i,e from the luggage lamp. It would be better to separate the camera from the luggage lamp and supply it via another circuit. I see that there is a "Vanity" circuit with a 7.5A fuse which could be connected to the this camera.

P.S : Not really sure what gizmos are classified under Vanity and where the leads go. Front or back?.

The vanity lamp doesn't apply to the Indian Grand Vitara.

The key here is to power the camera from a switch controlled source which can be isolated when the key is removed( e.g.stereo control power ) and not from a source directly supplied from the battery.

Such aftermarket devices should NEVER be connected to the same source that powers an ECU, fuel circuit or any other such critical functions.