Charging problems

[Dansline]

Car was dead a few week back put new battery on fine sins. But now playing up again. Scan tool says alternator is charging at 12volts but multimeter at the jump point says 14volts. Anybody had this issue befor

[cliffcoggin]

Did you have the new battery coded to the car? It needs to be done.

What in particular is "playing up"?

[Dansline]

Voltage at the DL16 plug is 12v and it's 14v at the alternator. Has had a new battery on it for a few week. But had now drained again 

[Magnet]

Hello Daniel,

Clifford has asked if you had the new battery coded to the car. Could you let him have an answer please.

In addition, 14v is marginally low - would prefer 14.5 ish - but that should not account for the battery drain in isolation, but just could ( in caps) perhaps point to a partial drain through the alternator itself. 

If you fully charge the battery and leave it connected, how long does it take to get to a point where you know it’s low enough not to be able to start the car?

What make of new battery did you buy as a matter of interest?

Kind regards,

Gareth.

[Dansline]

Snap on tester did have a option for reset battery so not done. Not sure on make of battery but it's not a cheap one that went on. And it seam battery went dead in 8 to 10 hrs from last drive. 

[Magnet]

Thanks, 

That’s an incredible drain time - pull of at least 7 amps! Not a parasitic drain, but more a monster eating your battery capacity! 
If it were mine:- 

I would recharge the battery and safely disconnect the plug on to the alternator before reconnecting the battery. Allow to ‘stand’ overnight, and test battery condition again. 
Check make of battery. 
Report back on outcome. 

[Dansline]

Going to do a battery drain test on it when back at work Monday. Think it's a exide

[cliffcoggin]

1 hour ago, Dansline said:

Snap on tester did have a option for reset battery so not done. Not sure on make of battery but it's not a cheap one that went on. And it seam battery went dead in 8 to 10 hrs from last drive. 

Nobody is asking about resetting the battery. The question, which has now been asked twice without an answer, is whether the battery was coded to the car. Unless that is done various electronic systems in the car will not work.

Having said that, battery draining in 10 hours suggests there is some electrical equipment running (dashcam, radio, lights, satnav for examples) while the ignition is off, or an electrical fault. Be aware that if the new battery is completely flat it may have suffered damage and need replacement again, so it's essential to resolve the electrical fault before buying another.

It would also be worth getting the alternator tested as they normally put out approximately 14.5 volts.

[Dansline]

It's a 2010 a4 b8. There was nothing on the snap on diagnostic tester for battery coding or battery reset. Charged the car up this morning and so far still OK. Think the new battery will be ok just have a really bad drain 

[Stevey Y]

15 minutes ago, Dansline said:

Going to do a battery drain test on it when back at work Monday. Think it's a exide

Hi if you did not code the battery in when fitted thats why the charge rate is up the ECU thinks its the old battery so carries on charging at the same rate so in essence you have cooked your new battery, did my daughters Q3 about two months ago recoded it [simple] and have had no problems since, the BEM controls the charging according to the information from the ECU, if the ECU still has the same information from the old battery it will continue to tell the alternator to charge at the higher rate regardless of the new batteries existing voltage, AGM batteries dont like overcharge and die in short order.

Steve. 

[cliffcoggin]

I give up.

[Stevey Y]

7 minutes ago, cliffcoggin said:

I give up.

Hi Cliff think I will join you, lights are on but no one at home.

 

[Dansline]

You asked if the battery was coded. I answered 

[Magnet]

So are you going to carryout the test I suggested Daniel?