Parasitic battery draw

[SA1]

Two good choices Tony. Have you or anyone else have cause to use a digital clamp - I might consider getting one if it makes the process a bit easier?

Hi Tony. I liked the HEX60-D the best, but will delay any purchase for the time being. I decided to buy an Amp clamp which I thought would be useful addition to my car tools (UNI-T201E) for £43, and will test that against my multimeter to see how close the readings are from each other and then decide about my multimeter. I will carry out more testing to my car week week when I receive the item. Cheers.

 

[SA1]

I have several meters including one with a AC/DC clamp. The clamp does make life a lot easier for measuring current flow.

Beware not all clamp meters can read DC current.

Yes LostKiwi - I am getting the impression they can be pretty convenient, and thought that I could also hook over my alternator cable, and maybe fuse box cables to check current draw when car shut down. I bought an AC/DC clamp.

 

[Tony Dyson]

Hi Tony. I liked the HEX60-D the best, but will delay any purchase for the time being. I decided to buy an Amp clamp which I thought would be useful addition to my car tools (UNI-T201E) for £43, and will test that against my multimeter to see how close the readings are from each other and then decide about my multimeter. I will carry out more testing to my car week week when I receive the item. Cheers.

If this https://www.uni-t.cz/en/p/clamp-multimeter-uni-t-ut201 is the clip-on ammeter you are intending to buy it's the wrong spec for your needs as it doesn't read DC Current!

 

[Tony Dyson]

If this https://www.uni-t.cz/en/p/clamp-multimeter-uni-t-ut201 is the clip-on ammeter you are intending to buy it's the wrong spec for your needs as it doesn't read DC Current!

Another look at the spec sheet and the range also needs to be lower than the one specified if you're looking for mA losses in either AC or DC circuits. if you ordered yesterday you should be protected with distance selling laws in the UK, let us know how you get on with the suppliers?

 

[mattkh]

Two good choices Tony. Have you or anyone else have cause to use a digital clamp - I might consider getting one if it makes the process a bit easier?

My project to make a 12v dc clamp meter is on the back burner.
In view of the current driving parameters, if you have a garage, I would invest in a trickle charger, and if you do not, then a solar panel charger left in the car will be sufficient.

 

[SA1]

If this https://www.uni-t.cz/en/p/clamp-multimeter-uni-t-ut201 is the clip-on ammeter you are intending to buy it's the wrong spec for your needs as it doesn't read DC Current!

My clamp-multimeter is the 210E so the spec is OK. I tried it in the morning and as my main battery is in the boot, I just opened the boot and clicked the boot light off, so the car was still be in its dormant mode. I tried measuring the current with the clamp (round neg wire) and after taking separate readings in triplicate (zeroed between each test) the reading ranged from 40-50mA which means my car is within spec.

Now I am beginning to think that I don't actually have an problem with my car (which is a relief) , and that either my old multimeter is either faulty when I measured the current previously or that the car was not totally in sleep mode when I originally did the test.

I was wondering if their is a way to test with my multimeter in the same way I carried out the test above (just opening boot)? Knowing that my alarm will going to go off if I disconnect the battery neg terminal (to do the test with the multimeter) or removing the alarm fuse, how can I carry out the test without my alarm going off and waking up the vehicle?

 

[Tony Dyson]

My clamp-multimeter is the 210E so the spec is OK. I tried it in the morning and as my main battery is in the boot, I just opened the boot and clicked the boot light off, so the car was still be in its dormant mode. I tried measuring the current with the clamp (round neg wire) and after taking separate readings in triplicate (zeroed between each test) the reading ranged from 40-50mA which means my car is within spec.

Now I am beginning to think that I don't actually have an problem with my car (which is a relief) , and that either my old multimeter is either faulty when I measured the current previously or that the car was not totally in sleep mode when I originally did the test.

I was wondering if their is a way to test with my multimeter in the same way I carried out the test above (just opening boot)? Knowing that my alarm will going to go off if I disconnect the battery neg terminal (to do the test with the multimeter) or removing the alarm fuse, how can I carry out the test without my alarm going off and waking up the vehicle?

Aah you wrote 201E back in post 22 which is a different instrument.
Get into the boot as you did previously and connect your multimeter between your batt Neg post and chassis in parallel with your main Batt Neg-> Chassis lead, when your meter is connected, then disconnect the main Batt Neg-> Chassis lead forcing the current flow through the multimeter, thus maintaining a Neg/Chassis link at all times, reverse the process to disconnect.

 

[SA1]

Aah you wrote 201E back in post 22 which is a different instrument.
Get into the boot as you did previously and connect your multimeter between your batt Neg post and chassis in parallel with your main Batt Neg-> Chassis lead, when your meter is connected, then disconnect the main Batt Neg-> Chassis lead forcing the current flow through the multimeter, thus maintaining a Neg/Chassis link at all times, reverse the process to disconnect.

Oh yes I see my numerical error regarding the G clamp.

I tried your suggestion and this time the alarm didn't go off. I tested with my multimeter and it wasn't a static result but varied between 40-50mA. I think when I originally did the test and had some concerns about the draw on the battery, something in the car must have still been awake to draw the 200mA that I was seeing, maybe the motion sensor inside the car when I had the door open (door light and lock off), I'm not too sure.

I tested my neg chassis lead with the G clamp and get 3 readings of about 40mA. I did find that their was some uncertainty when using the clamp as it seems very sensitive; I got a couple readings of around 80mA - I think I just need to get familiar with using it and found it best when no part of the clamp was touching the actual wire when clamped around to get more consistent results i.e. when I left a bit of an air gap.

I also noticed that whenever I change from AC to DC amps their is always a figure of about 200mA (I know I have to zero each time but why is that figure always there?) - I am not able to wipe this figure (apart from zeroing) even after taking the battery out/in. Also the clamp using the leads was 0.2V higher than my multimeter was showing using the same leads, which is a bit mystifying? I like the G clamp and think it's useful but I would have thought the voltages using each instrument would be the same.

I think that when the old battery started to lose charge in the space of a week when I hadn't used the vehicle, the battery was probably on its last legs (3 years old - but 5 year guarantee so expected it to last longer). Anyway, I think I will monitor the voltage (although not sure which instrument is the more reliable for that!) periodically just to make sure that every is ok, which it seems to be based on the current draw readings.

Thanks.

 

[Tony Dyson]

Oh yes I see my numerical error regarding the G clamp.

I tried your suggestion and this time the alarm didn't go off. I tested with my multimeter and it wasn't a static result but varied between 40-50mA. I think when I originally did the test and had some concerns about the draw on the battery, something in the car must have still been awake to draw the 200mA that I was seeing, maybe the motion sensor inside the car when I had the door open (door light and lock off), I'm not too sure.

I tested my neg chassis lead with the G clamp and get 3 readings of about 40mA. I did find that their was some uncertainty when using the clamp as it seems very sensitive; I got a couple readings of around 80mA - I think I just need to get familiar with using it and found it best when no part of the clamp was touching the actual wire when clamped around to get more consistent results i.e. when I left a bit of an air gap.

I also noticed that whenever I change from AC to DC amps their is always a figure of about 200mA (I know I have to zero each time but why is that figure always there?) - I am not able to wipe this figure (apart from zeroing) even after taking the battery out/in. Also the clamp using the leads was 0.2V higher than my multimeter was showing using the same leads, which is a bit mystifying? I like the G clamp and think it's useful but I would have thought the voltages using each instrument would be the same.

I think that when the old battery started to lose charge in the space of a week when I hadn't used the vehicle, the battery was probably on its last legs (3 years old - but 5 year guarantee so expected it to last longer). Anyway, I think I will monitor the voltage (although not sure which instrument is the more reliable for that!) periodically just to make sure that every is ok, which it seems to be based on the current draw readings.

Thanks.

Alarm didn't sound because you maintained connectivity between the Batt Neg and the chassis and the alarm didn't suffer a power failure.
The published accuracy of these budget instruments are I believe at least ambitious, genuine accuracy can cost considerably more than what you paid for the meter but reading from two budget instruments will at least provide a closer average of what you're actually looking for.
The same has to be said for the jaws of a clip on ammeter for a clamp capable of reading both AC and DC currents, they are a complicated component, the laminations have to be configured and oriented to pick up the circular flux generated by AC and the linear flux of DC so the fluctuations and anomalies you mentioned are unsurprising, you will also probably find reading your instructions there will be specific areas within the jaws that will be AC and/or DC sensitive and advice to channel the cores being measured through specific areas of the jaw/s.

So the upshot is, you're happy there isn't a drain that you're worried about? so is it a result then?

 

[SA1]

Alarm didn't sound because you maintained connectivity between the Batt Neg and the chassis and the alarm didn't suffer a power failure.
The published accuracy of these budget instruments are I believe at least ambitious, genuine accuracy can cost considerably more than what you paid for the meter but reading from two budget instruments will at least provide a closer average of what you're actually looking for.
The same has to be said for the jaws of a clip on ammeter for a clamp capable of reading both AC and DC currents, they are a complicated component, the laminations have to be configured and oriented to pick up the circular flux generated by AC and the linear flux of DC so the fluctuations and anomalies you mentioned are unsurprising, you will also probably find reading your instructions there will be specific areas within the jaws that will be AC and/or DC sensitive and advice to channel the cores being measured through specific areas of the jaw/s.

So the upshot is, you're happy there isn't a drain that you're worried about? so is it a result then?

Yes - I'm happy their is no drain from my battery, it's nice to know that.
Thanks Tony and others for your comments, which has been a great help.

 

[Tony Dyson]

You're welcome, glad to help.