Hi everyone well i really need some help with my 1.2 fiat bravo. Every time it gets cold my battery dies! ive jumped it and it runs then dies again the next morning

heres the strange part - this is my 3rd battery in 2 years! because i obviously assumed the battery was dead and got a new one but they cant all be defective/lacking power!
It only happens when the weathers cold and the alternator/battery light has never come on when its running! :bang:

I dont know wether its the alternator or a parasitic drain some where in the car, there has been a stereo and alarm/remote locking box fitted (over a year ago) but if these were draining the battery surly the battery would die regularly (over periods of inactivity?) not just when its cold??

any thoughts?

can you use a multimeter. if so check the output from the alternator. should be 14.7 volts dc

then check you battery voltage last thing at night and first thing in morning, see if it is decaying or if something is active

or buy a good battery with a good warranty

yea i used my multimeter on the battery but as its dead its about 11.7 v, but to test the alternator wouldnt the car need to be on? theres no way i can jump it until my family comes home later.

The batterys have 2 year wareentees but i dont think their the problem as its unlikely to keep getting dodgy ones, is there a possibility the batteries are too small for my car?

All lead/acid batteries work on a chemical reaction. Higher temperatures act as a catalyst on this reaction, so all batteries work better during the summer.

It would seem as though you have a permanent drain on your battery.

Remove one of the battery terminals and connect an ammeter between the lead and battery post to check.

Dave.

yes the car needs to be running to check alternator output

Thanks, Davren i was planning to disconnect my negative terminal and put the MM between it but my crappy thing only seems to read up to 24ma then jumps into amps! am i right in thinking i need to get in the 100-1000 ma range?

and if its high start removing fuses one at a time until the ma drops?

what is a normal reading?

Do you mean it reads 24mA when connected between the battery and lead or the meter only has a 24mA scale?

Is it a digital or analogue meter?

Most digital meters have 20mA and 200mA scales and a 10 or 20Amp scale via a seperate +ve red lead socket on the meter.

Dave.

As you can tell im a noob when it comes to MM, its this one http://avslgroup.com/product/600.005UK

its digital, and the only refernce i can see to mA on the scale is 40mA and 24mA which are at the same point as 1.5v and 9v

can i do the test with this?

best thing to do - run it down to wilco motosave they do free battery checks - my transit vans the same at the moment the car is fine -think its just the cold weather

That meter has 2mA, 20mA and 200mA ranges for DC current (the red sector 3 o'clock to 5 o'clock on the dial).

Make sure everything is switched off on the car (close all doors and boot so interior lights are off).
Disconnect the negative lead from the battery.
Connect the black test lead plug to the COM socket.
Connect the red test lead plug to the μA mA socket.
Connect the black test lead probe to the disconnected negative battery lead.
Connect the red test lead probe to the negative battery post.
If you connect the meter leads the wrong way round, the meter display will show a - (minus sign) in front of the reading but it doesn't matter, the numbers will be the same.
Do not switch anything on or open a door while the meter is connected. Interior lights will use more than 200mA and blow the fuse in your meter.

Start by using the 200mA scale. If the reading shows less than 20mA, switch to the 20mA scale.

The absolute maximum reading should be no more than 100 mA (0.100 Amp), ideally it should be lower than 50mA (0.050 Amp). It will never be 0 because of KAM (Keep Alive Memories) e.g. for the radio.

Dave.

Thanks Davren, i managed to figure it out and took the readings just before you posted!

basically when i attach it the MM displays a high number e.g. 180-200 mA but instantly starts to drop, it drops all the way down to about 30 then levels off, is this normal?

I took the reading with everything off and alarm disarmed, the car hadnt been touched for 2+ hours so all systems should have powered down

So am i right in thinking its not a drain somewhere? as even though the alarm wasnt armed it would have been drawing its load right?

So all i can think of is the alternator but the light has never come on, and also could the alternator be under performing but still charging the battery enough to run it normally just not enough for cold mornings? or would the alternator only either be working or not and either charging the battery fully or not at all (resulting in a dead battery all the time regardless of weather?)

A 30mA drain is acceptable.

The battery will need more charge from the alternator in cold weather because you will be using more consumers. e.g. heater, heated rear window etc. and the starter motor will draw more current to turn a cold engine.

You can check the alternator output with the multimeter but you need to get the battery fully charged and the engine started first.

Dave.

just got a jump and tested the current its 13.7(75-77) am i right in thinkings its a weak charge? as isnt the norm 13.8-14.8? could this reading be irrelevent due to the car just being started? ive left it running so should i take another reading in 20 mins or so?

Charge should be between 13.7 and 14.3 Volts, and it should stay within that range when loaded.

Let the car run for 20 minutes with everything switched off, then, with the engine still running, switch on the headlamps, heater fan and HRW (Heated Rear Window) to load the system and check that it's still within range. I it's not, then the alternator or it's wiring or earth connection could be faulty.

Dave.

cheers for all the help, i re took a reading after about 40 mins at idle and the charge was only 13.6. I then loaded the car with HRW, Heater, headlamps on full beam and the reading went down to 12.8! so it is the alternator right?

shall i check the wiring etc or is it more likely the actual alternator needing replacing?
Thanks once again

LIDL have smart battery chargers in now

cant do any harm sticking it on charge every now and again (they also have a automatic test and recovery inital "charge" cycle)

http://www.lidl.co.uk/cps/rde/xchg/...&district=+&street=North+Street&ar=10&nf=True

Thanks for the heads up mate, i may get one just incase but i think its deffinitly the alternator! it seems to be strong enough to start normally just not strong enough to start the engine in the cold

whats the normal procedure when a dying alternator has been found? check wires? (take readings with MM etc) then test belts for tension? if nothing is found get a new one from scrappys?

kaosNW said:

Thanks for the heads up mate, i may get one just incase but i think its deffinitly the alternator! it seems to be strong enough to start normally just not strong enough to start the engine in the cold

whats the normal procedure when a dying alternator has been found? check wires? (take readings with MM etc) then test belts for tension? if nothing is found get a new one from scrappys?

Click to expand...

the alternator doesn't start the car the starter motor does

It is worth checking all the terminals are clean and rust free (also the earths follow the black wire from the battery)

if you have a healthy alternator will push about 14Vdc back to the battery when running after start up...

if the belt is slipping you will normally hear it on start up (squealing)

do you do a lot of short journeys?

normally drive to and from uni about 15 miles each way, 30-60 mins a time with the odd quick trips

the belt seems tight and no squealing, so i probably have to take a trip to the scrappy

the reading i took with everything turned on was only 12.8 but that was without revving, does this sounds like the alternator is the problem?

@ kaosNW...... Sorry, my previous post #14 should have read as follows;


Charge should be between 13.7 and 14.3 Volts, and it should stay within that range when loaded.

Let the car run for 20 minutes with everything switched off, then, switch on the headlamps, heater fan and HRW (Heated Rear Window) to load the system. Increase the engine speed to about 1500-2000 rpm and check that it's still within range. If it's not, then the alternator or it's wiring or earth connection could be faulty.

As you got 12.8 Volts, loaded on idle, I suspect the alternator will be OK, but check it again as above to be sure.

Dave.