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Battery re-connection issues

panhead

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Not if you have a charger that goes to 'float' mode when the battery is charged.
I have 3 "Battery Fighter" s which are always connected when I am not using the cars. Inconvenient to be disconnecting/connecting when the car is needed, but far less inconvenient than a flat battery.

The alternator can pump out all sorts of volts to change the cars battery including zapping it when in a desulphation mode. Yes, the car's charging system can desulphate a bettery... As such, one must expect that Holden ensured all the devices powered by the battery are robust enough to cope with the voltages and waveforms pumped out by the alternator (especially the desulpation mode waveforms)...

So an external smart charger doesn't do anything worse than the alternator/generator would so there is no need to disconnect the battery from the vehicle.

As is, the workshop manual says the same though they do say to check that the battery cable terminals are tight... The manual also warn that if a battery has discharged to 65% of capacity (12.45v @ 25c) that it should be charged (using an external charger) before returning to service (driveing the car)...

not with a charger that is designed to be attached while the battery is connected - old natty ones, not so much. modern trickle/maintenance chargers can be retrofitted to the vehicle permanently.
I thought so.

I never disconnect any of my SLA batteries if I'm trickling or fast charging them.






.
 

tommy_z

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If you disconnect the battery, the TPMS must be relearned.
Purchase a TPMS tool from eBay for ~$20 and you’ll be fine to reset your TPMS anytime (this will include if you need to put the spare tyre on for example).
 

Stingrayviathenorth

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Check all fuses as one/some may have inadvertently blown on reconnecting a fully charged battery (though i doubt it unless the terminals sparked when fitting the battery)...

The tyre pressure sensors have an internal non replacable battery with a 10 year service life but doubt all would have died at the same time. The tyre pressure sensor can be read to check pressure and battery level using a Holden test tool or some of the better ebay clones.

As is, the tyre presure sensors will transmit if there is a pressure change which is 2psi(?) different to the last pressure reading internally stored within the sensor itself. Any transmitted data is picked up by the the Remote Control Door Lock Receiver (RCDLR). The RCDLR passes this pressure data to Body Control Module (BCM). Finally the BCM sends the data to the Driver Information Center (DIC) for display. Pressure transmissions can occur when the tyre pressure sendors are either in STANDBY or DRIVE state but the TPMS system needs to be awake to pick them up....

If the vehicles battery is disconected, all the tyre pressure sensor ID's are retained by the BCM but tire pressure information is purposefully discarded since the system has no way to know how long it's been powered down and what state the tyre pressures are at. As such, all dashes are shown for each tyre pressure position within the DIC. Also, the tyre pressor sensors will be in a standby state (obviously as the car can't be driven when it doesn't have a battery). In such cases the tyre pressure sensors wont transmit anythin unless the pressure changes but even then the cars TPMS sis dead to the world (no power after all)... So, when reconnecting teh cars battery, they cars systems should wake up and the tyre pressure sensors will only transmit data if the tyre pressure changes or the spensor wakes up (via an internal accelerometer). The tyre pressure sensors will wake up if driving >40kph for at least 2 minutes and at this time the sensors should transmit their pressure readings and they should be displayed in the DIC. If there is a fault in the TPMS, a DTC is set.

So... check for DTC's... go for a drive and stay above 40kph for more than 2 minutes (hard to do with stop signs and traffic lights so get on a freway)... If the system still doesn't work, you'll need a TPMS test tool to read the sensor battery status...

As to the outside temp sensor, i have no ideas...
Such knowledge!!
 

Skylarking

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If you disconnect the battery, the TPMS must be relearned.
The workshop manual specifically states that when disconnecting the cars battery, each tyre sensor‘s ID is kept within BCM and only tyre pressure data is deleted. Thus no relearning is required...

When you reconnect the cars battery, you just need to go for a drive at >40kph for >2 minutes and all should be peachy. But doing such a drive may not be as simple as it sounds if you live in crowded suburbia. Those damn stop signs and traffic lights everywhere make it a stop start situation when you really need a >2 minute run @ >40kph, so the hint would be to find a freeway and all should be ok after this w minutes ;)
 

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myls362

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Thanks so much for all the posts.

I got in the car this morning and the outside temp was back! Drivers window still worked. I flicked the centre display to TPMS. As I was driving along each tyre monitor progressively connected.

Another interesting thing was that yesterday the LS3 wasn’t cleanly starting. It seemed to take a bit longer to start. This morning it started as per normal.

I had no idea just disconnecting the battery would cause a few issues. Back to Bathurst....
 

stooge

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Battery is the original AC Delco. I just used a lead acid charger. eBay special.
that is fine.
pretty much all flooded/wet cell sealed(maintenance free) batteries are calcium and your charger unless faulty would have been ok but it might pay to either get the battery tested or replace it.

sla batteries do not like being heavily discharged or sitting long periods without any charge and that is why the guys are saying to use a maintenance charger to keep it charged while the vehicle sits for long periods and connecting a charger directly to the battery while the vehicle is still connected is fine.
 

tommy_z

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The workshop manual specifically states that when disconnecting the cars battery, each tyre sensor‘s ID is kept within BCM and only tyre pressure data is deleted. Thus no relearning is required...

When you reconnect the cars battery, you just need to go for a drive at >40kph for >2 minutes and all should be peachy. But doing such a drive may not be as simple as it sounds if you live in crowded suburbia. Those damn stop signs and traffic lights everywhere make it a stop start situation when you really need a >2 minute run @ >40kph, so the hint would be to find a freeway and all should be ok after this w minutes ;)
AH. Thanks for clarifying. I missed the second part...after changing my battery earlier this year I just got my relearn tool out as all four tyres were showing as blank on the DIC. Didn’t know I just needed to take my car for a drive!!:eek:
 

Stingrayviathenorth

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Wouldn‘t be sure how to interpret such a comment if it wasn’t for the thumbs up on the post :p

But I assure you, my memory isn’t what it used to be. However, I can still read :p As such, having a VF workshop manual (in a clumsy PDF format) makes it a little easier to understand some of the cars systems.... A link to the workshop manual is provided in this post ;):cool:
Yes, it was a genuine comment. Looks like I should have a copy of the VF Workshop Manual
 
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