alternator? battery? or both?

[ff2007]

Hi all,

Looks like I was wrong when told you all about the 15A sticker on top of the battery as the its production year, cause under the battery is an arrow point to 6 and there is also 07!

Looks like this battery is produced on 6th month of 2007, and it was recharged on Jan 2015?!

Anyway, today did change the battery with a new one. Should test it soon!

I hope this all was caused from a battery!

 

[ff2007]

Update: Even with the new battery, again the same issue appeared! 

Not sure what else to check now! Could this be a TCM issue? Cause of P0790 and P0700?

 

[madmole]

Whats the voltage in the battery now? if <12.2 then you have a parasitic drain that's emptying it. Need to pull fuses till you find the source

 

Radio or dash I suspect

[ff2007]

6 hours ago, madmole said:

Whats the voltage in the battery now? if <12.2 then you have a parasitic drain that's emptying it. Need to pull fuses till you find the source

 

Radio or dash I suspect

12.69 V. I don't think its a drain anywhere because tested also the Amperage with a clamp meter to see if there is any drain, when engine and everything is off, it showed 0.2A.

And just got the info from battery producer, battery date is January 2015.

[madmole]

12.7v is fully charged, so its not your battery

200ma is high but not excessive and I suspect the car will reduce that with time as it closes systems down. So you have another issue

When it doesn't start

Does the solenoid click when you turn the key?

Does the engine turn over? slow or normal speed?

 

[artscot79]

with engine off ecu and cluster still active for up to 45 mins so its probably just that if all the codes keep pointing to the tcm then theres a fault somewhere in that system I think that's causing the starting issue ive seen a few where if the management light comes on theres starting issues till the codes cleared

[ff2007]

1 hour ago, madmole said:

12.7v is fully charged, so its not your battery

200ma is high but not excessive and I suspect the car will reduce that with time as it closes systems down. So you have another issue

When it doesn't start

Does the solenoid click when you turn the key?

Does the engine turn over? slow or normal speed?

 

Solenoid in the transmission? If you're refering to starter relay in the fusebox, then yes, it is clicking at the time I put ignition on while warnings are on the dash, and during that time PRND flashes and it changes randomly between PRND on screen.

[ff2007]

Hi everyone,

Thanks for the comments everyone. 

I hope this tiring issue with the car is going to an end.

As you may remember the voltage values I gave on this thread 14.5v was measured from a multimeter (Fluke) which I believed it was really so! Today I went to clear the codes and wanted to see what the Bosch diagnostic tool says about the voltage when everything was switched ON (AC, win heater, headlights), at it read 13.4v! Tried revving and it went to 13.7v! I thought this may not be accurate! Came home and measured with Fluke, again 14.3v! Then I decided to measure it with an analog multimeter and guess what? Analog multimeter gave 13.2v-13.3v!

 

I think now these results tell something important! 

[madmole]

Yes, that the fluke has a lower internal resistance

Alternator is fine if its pushing 13.7v with all load on. Ideally though you should measure the current as well

 

[ff2007]

Huh? Shouldn't it be more than 14v to properly operate?

[madmole]

Anything over 12.8 is charging the battery, older cars charged at around 13v. its only modern cars that have smart alternators that can allow for cold etc should go higher and may max out at 15v for short periods. The higher the voltage the greater the difference and the potential to force charge into the battery (the actual amount going in is the current), but higher voltages also cause things to warm up and can shorten the battery life if overused

A trickle charge at 13v is actually better than shoving a load in at 14.5, but on a cold morning, with a depleted battery from starting the engine, the alternator will stick out up to 15v for a while to get the battery topped up as quick as possible then ramp down the voltage as it fills up

Smart chargers will also do short high voltage pulses to break down sulphation in cells if needed

 

[m1tch]

Could the issue be that the alternator is constantly charging the battery rather than only charging the battery when needed? Not sure if these alternators are clutched to turn the charging system on or off etc.

[madmole]

battery would get warm and gas off. it would loose fluid.

They are not a clutch physically, they are voltage controlled internally by electrics. The colder it is and the lower the battery voltage the higher the output voltage

If you start the engine while watching the voltage and leave it, You should see the voltage be high immediately after the start and then slowly come down as the battery is charged

[mjt]

11 hours ago, madmole said:

Anything over 12.8 is charging the battery, older cars charged at around 13v.

I'd beg to differ about that. A fully-charged lead-acid cell has a voltage of about 2.2V depending on temperature so multiplying that by 6 cells gives 13.2V. To trickle-charge a fully-charged battery would therefore need in excess of 13.2V, maybe 13.4V. Even on cars that do not have Smart Charge and use standard, rather than Calcium, lead-acid batteries it would be normal to see the alternator voltage go over 14V immediately after starting then slowly drop back to just over 13.2V.

[madmole]

Theoretically that's correct, but in reality most batteries are not perfect and a working full charge is considered 12.8v and above (95% plus). In reality any voltage even slightly above the resting voltage of the battery will result in some charge going in (however slowly). But yes you would expect >13.2 volts min on a brand new or modern high capacity system. After a start, the battery will be partially drained and so modern system will wap in more to bring it up quickly