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Discussion Starter #1
HI,

My car battery on Zafira b 2006 1.8l Petrol goes flat every so often.
I have just replaced it for a Bosch 60A battery, but I have realized after not using it for a few days the Voltage dropped 12.3V to 11.5.
I have tested the alternator (used a clamp meter, put it around the red cable next to the battery) and it’s showing 32A.
When I turn the lights and heating on it drops to 29A.
I thought that the alternator output should be around 80 or I’m wrong?

I would appreciate any help.

Thanks
Robert
 

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Amperage (current) is given by the loads not the alternator. When you turn consumers on, seems that the battery supplies the difference, but its a bit odd.
However, I would check for parasitic drain. Youtube is full on how to. I use a thermal camera, takes me 1 min to find the culprit. Don’t let the battery go flat or its gonna be garbage. Recharge it asap.
 

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run the vehicle with nothing on. Get a voltmeter and check the charge. it should be at least 13.8 volts.

if the battery has seperate screw caps for each cell, keep the negative on the battery and then put the positive tip of the voltage meter in the cell and they should all be at least 2volts.

if one is zero or way off, its the battery.

It used to be far easier to check for voltage drain. Make sure you have all the security codes fornyour car justnl in case. and make sure to read what the owner manual says.


Then pull the battery out of the car, give it a full charge with the battery cap open, DO NOT smoke near a charging battery and ALWAYS CHARGE IN A WELL VENTILATED ROOM.

Once the battery is fully charged, check the voltage again.

Depending on what kind of options you have check perhaps the interior blower fan is staying on even when the vehicle is off...
 

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What voltage are you getting across the battery with the engine running?
It should be between about 13.8 to 14.2 volts.
If you're not getting that, then either your alternator or the wiring to it are likely to be faulty.
If your Zafira is the same as my Astra, there are three or four red wires on the battery positive terminal, you would only get an accurate amp reading from the alternator if you put the clamp round the wire to the alternator only, and, as said above, the amps produced depend on the load being taken by what is switched on. The important thing is the voltage at the battery.
 
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As @Alan G H says, or as @TTT says, check for parasitic drain.
Switch off the car and absolutely everything in the car, don't forget about any usb chargers, cameras etc. Disconnect the positive terminal from the battery and connect the amp meter set to mA. As you will connect it the amp meter will display number 1 being over-current as it is exceeding the range, as all electronics are awaken. Leave it like that for about 5min and take reading, you will see the readings dropping. After said 5min shouldn't be more than 50mA as everything should go to sleep mode. Anything more points to the parasitic drain. The most common culprit is grounding under the battery tray, if not wet uec.
 

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Discussion Starter #7
Thanks for all replies.

The battery while engine running is showing 14.2V which is good, I was just worried about the alternator giving out 32A as I thought it should be more.

Disconnect the positive terminal from the battery and connect the amp meter set to mA.
I have also tried this many times but after leaving the car idle for 1 hour I get a reading of 6ma, again which I think is normal.
The only other thing which I think might be causing the battery to drain are the back exterior lights, they are getting some water inside.
I bought a new light but it came without the gasket, and I’m struggling to find the correct seal.

A few weeks ago, I have unplugged all rear lights and left it for two days, but also then the battery voltage dropped, so maybe it’s not that the fault.

Very difficult to pinpoint, as I thing something drains the battery but not all the time.

Anyone has any ideas how to get to the bottom of this, I would really appreciate it.


Thanks
 

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Go out to your car at night to check if you can see any lights on , it could be simply a switch that’s not working properly like say the glovebox light or boot light etc.
 
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Discussion Starter #10
Try to correct the grounding under the battery tray, it is known issue. Another thing to check is the uec if getting wet.
What do you mean by correcting the grounding?
Will check the UEC hopefully over the weekend.

Go out to your car at night to check if you can see any lights on , it could be simply a switch that’s not working properly like say the glovebox light or boot light etc.
Thanks for this, have just checked but all lights are off.
 

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What do you mean by correcting the grounding?
Will check the UEC hopefully over the weekend.


Thanks for this, have just checked but all lights are off.
a bad earth terminal causes issues on many manufacturers cars as the circuit can try to close even using the car aerial, radio chassis... get a earth strap from your local autostore... you can get them in set lengths... find a place to bolt to the gear box and then somewhere near the battery. check the battery terminal and that cables connection to the chassis.

what kind of aircon does it have?
 

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Under the battery tray there is a bolt welded to the chassis where one or more grounding wires are joined to the chassis. Undo the nut, clean everything, put it back together.

For uec job buy a contact cleaner.
 

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Discussion Starter #13

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You can find electrical contact cleaner at Screwfix or Toolstation as well if they are nearer.
 
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