Does anyone know about Current Draw on a car?

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Does anyone know about Current Draw on a car?

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Apr 11, 2005
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Basically my car batt goes flat after a few days of non use, thought it was the car radio.

So i did a current draw test on the battery and got a reading of .14 on the multimeter.. Now this reading is supposed to be 0. So obviosuly something was a miss, Disconnected the radio, and the same reading was still there. So then i pulled fuses until i found the culprit, I did and it was the Cig lighter/radio/alarm sensor and led/interior light/map reading light.

So i disconnect everything on the circuit by removing the plugs from the back on instruments, and the reading still remand, i pulled the alarm fuses that was on another circuit and it dropped to .11... Its def that circuit... Its doing my head in.

The car is a Fiat punto GT
 
Sounds like the battery has had it, though the draw is 0.14A this should not drain the battery that quick. Batteries can appear to have a good voltage but when tested have little capacity which I think is what yours is lacking.
 
Thats what i fort, but happens on new batterys/semi used batterys.

I have ordered another. Hopefully this will be better.
 
I had similar thing once, drained a battery over a weekend & the drain was barely noticeable. Turned out to be the cig lighter. One of the elements had broke causing a short, the thing was obviously on constant warmup.
My dad had the new shape civic (03 -plate, not the nasty split rear screen) and that battery would drain if the car was stood for two weeks.
Honda admitted they knew about this, it seems that by shortening the bonnet, they had to cut down on battery size & so used the smallest they could get away with. Normally, this wouldn't be a problem but going away for a fortnight was. Seems the alarm, radio & onboard computer systems performs some sort of very frequent test which draws a minute current.
Annoyingly, there wasn't room for a larger or even second battery so we had to buy one of those booster packs & make sure it was fully charged.
Bit embarrasing really, having to jump start a brand new car when you come back off holiday.
 
0.14amps is not a big enough drain to worry about unless you only use your car for short journeys and not very often.

lets imagine your battery was rated at 100amphours, a 0.14amp drain would take 100/0.14hours to fully drain, that is 714hours, or one month, although once the battery is half drained you would expect to have problmes starting so you have what we call a 2 week drain period, which is acceptable.
 
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I use my car mainly at the weekends, no need to use it in the week unless im off work.

I can do a journey say for example, to alton towers which is 1 hr 40min drive from me, then back home again. Leave it for 4/5 days and it will be flat.

The alternator/starter motor has been checked and its fine. The problem has been with the car for a few years, but its only just really started to bother me.

I replaced the battery pretty much when i got the car in 2005, it still did this, so maybe it was a dodgy battery. At the moment im using a less powered one and smaller which was tested on an electronic battery tester before use and got the green light. Now its failing as its getting drained,

Ive ordered a newer one.. 065 60amps. Ill see how that reacts when i put it in at the weekend,
 
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My stilo battery drained completely during a 5 week spell when I was in hospital and convalescence. It was about 3 yrs old. I was told the electric locks and clock were enough to do it. The calculation above would confirm that , I think.
 
An alternative worth considering is to buy a solar charger, leave it connected to the battery (some cig lighters aren't permanently live) & place the panel in sunlight. It's amazing how long a battery will last with a constant trickle charge, even overcast days will provide some charge.
 
Ok with new battery
12v 55ah i get a current reading of 0.11 that was reading 12.60v at 1830 hours

The old battery
12v 44ah i was getting a current reading of 0.14 that was reading 12.30v at 1820hrs

Does anyone know what kind of amps a tiny siren battery would take, becuase i have one in my siren and maybe thats taking a bit, but without and unable to disconnect it im unsure.
 
i guess you mean the backup battery in the siren? in my experience they draw very little current, nothing compared to the alarm module when it is armed. even a basic alarm can easily draw 0.1amp so maybe that is your drain.

you've increased your battery capacity significantly so it should be able to handle the drain much more easily, but the car will need to be used every week for at least a few hours.
 
By coincidence?? I have exactly the same current draw (0.14A) on the battery with everything turned off. I traced it to F53 on the dash fuseboard.

This fuse feeds the hazard warning & indicator lights plus the dashboard. When I pull.push this fuse in you can just hear a faintclick and the needles jump.

As I presume this is feeding the clock etc display My question would be is this normal for a F53 fuses.
 
Hi,
Had a similar problem on my bravo recently, after a bit of searching turned out to be the internal boot light constantly lit..faulty switch. Try opening the boot and check if the light is warm..if so the light has been on constanly.

On another point, the measured drain of 0.1A (100mA) seems a tad on the high side, any car I've measured recently reads between 30 - 60 mA.

John.
 
Thanks Genghis. I have a rockbottom base model that doesn't have a boot light. I don't think that would be on F53 anyway. The problem is isolated down to F53 and it's fed ccts which are the Hazard warning, indicator and dashboard. The current drain is with the car in a static state

Could I ask if anyone with a type 2 punto could check on F53 on the dashboard fuseboard (or even across the 70A fuse in the middle of a group of 3 in the engine compt fuseboard) You would need a meter that has an Amp range not just a mA range unless it was at least a 200mA.
 
Hi,

I have exactly the same problem as Cusco above. A constant 250mA drain. I traced it first to something attached to the F1 fuse and then traced it further to the F53 fuse in the internal fusebox i.e removing F53 removes the current drain. As Cusco says this fuse supports; hazard warning, indicator and dashboard. As the clock is constantly on I decided to remove the instrument panel and test it again, the drain remained so I guess it's not the dashboard!?

Even though this fuse has nothing to do with either the boot light or the stereo I tested both i.e. I removed the stereo head unit entirely and placed a digital camera in the boot to witness the light going out.

So any ideas? could it be the body computer (multi-timer unit)? Cusco, I know it was 2 years ago now but did you get it resolved?
 
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