Battery Very Very Low !

[pauldavidthomas]

I've not used my B8.5 for quite a few months, perhaps 6... I thought I'd go to the garage and turn the engine over, yes, perhaps a little late.

Able to unlock and get in. Alas, it refuses to start - nothing. As such, I think the battery has discharged.

I do have a big 'ol powerful Sealey Road Start RS103 :-

https://www.sealey.co.uk/product/563719 ... mp-starter

That I use on my old landrover defender.

What would you guys suggest I do ? Pop the bonnet and put a trickle charge on her or use the Jump Starter connected to the battery in the boot ?

I'll have do a little drive to borrow a trickle charger from my parents and I'm pretty sure it suggests you disconnect the battery to run the trickle charge, which I really would prefer not to do !

Other than that she's say in the garage looking very pretty !

Suggestions appreciated.

[G30001]

I would stick it on trickle charge via the engine bay connection.

If it is still unlocking then it isn't dead, leave it a day charging and then take it out for a good run let it heat right up get rid of any condensation.

Have ypu got VCDS? I found my car throwing up various sensor errors when the battery got low (lots of <10 mile journeys) since I charged it up it has been fine.

[johnnydog]

Depending on the type of charger you have, you may need to jump start the car with the battery pack and run it for a few minutes to put some degree of charge into the battery because most chargers (including smart chargers) won't charge a totally flat battery. Alternatively, you may be able to get some charge in using the 'repair' function on a smart charger. Whichever way, connect the jump pack or smart charger (set on the AGM or Stop / Start function for charging) via the positive terminal under the scuttle and the negative lug near the nearside strut rather than direct onto the battery. You should not theoretically 'charge' a totally flat battery using the alternator, but to get some charge in it just for charging purposes, it should be ok.
The battery is likely to be shot at, and although it may hold some degree of charge, it won't hold a 100% by any stretch.
AGM batteries don't take kindly to being left totally discharged, so be prepared to fork out for a new one. The original spec was an AGM battery, but despite posts in other similar topics to the contrary, it must be replaced with another AGM battery, which ought to be programmed to the car. You may get away with not programming it, but that is the recommendation.
You may get some warning lights on the dash, such as suspension faults lights, but this is because the car has detected a low battery voltage, and shuts down some systems. These faults may have to be cleared when the battery is replaced.
There are topics on battery issues if you search dash warning lights or battery related topics.

[rrated]

Do you have a multimeter?

The battery's voltage will tell you a bit about its state. Anything below 12 volts is often irreparable with anything but an intelligent charger (as mentioned above), and even then, depending on how quickly it discharges again could indicate a faulty battery. A weak battery will put extra load on the alternator and can burn that out as well.

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[pauldavidthomas]

Ok, I'm going to go with the intelligent charger and if needed I've got the kick up the arse starting option. I'd rather go low and slow.

It's only because it's been in the garage for thinking about it, 6 months. I'll get the battery up and running, give her a decent run and then put her back into lock down !

[Rusty Racer]

If you have power in the garage it’s a no brainer to get yourself a Ctek charger to save the battery if nothing else.
As above the car really doesn’t like a flat battery!!

[hindsight]

Apologies for jumping on this thread but has anyone installed a ctek charger in their RS4 so that the bonnet can be fully shut, car alarmed whilst the charger is operating?

My car is always garaged but I'd like it locked and alarmed whilst charging, for insurance purposes. I've read that you can get quick connectors to make connection/ disconnecting easy but that not sure how easy that us to do and whether boot needs to be ajar / car unlocked.



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[MJ_RS4]

Hi, using the crocodile clips to connect to the terminal connectors as Johnnydog describes I’m able to close the bonnet and lock/alarm the car with the ctek running. I’d recommend ensuring the cable runs out from the top/near the windscreen part of the bonnet as there seems to be a little more space around this area so not to crush the cable...

[HPsauce]

There's always a way in for charger cables through boot/door/bonnet seals or cracks, they don't need to be that thick.
The charger isn't drawing much power from the mains (relatively speaking) so, wherever in the car it's located, the mains/extension lead to it can just be lighting standard.
You might only need 2-core which can actually be pretty thin.
And the cables from the charger to the battery are usually not that thick either and easy to extend if the charger can't be in the same compartment as the battery.

And obviously if the car is in a garage the charger unit can be outside it.

[Rusty Racer]

I have connected a fly lead to the positive terminals under the flap in the scuttle panel so me ctek plugs straight in without crocodile clips. There’s enough length on the cables to put the charger behind the near side headlight and close the bonnet

[pauldavidthomas]

Well.... I've got it all sorted.

I tried a Noco Genius G3500. It indicated the battery was too low to determine what to do with it. So, I plugged a Sealey ROADStart into the battery in the boot. Left if 3 mins and then was able to start it up without an issue. Took it for a 30 min drive to get some juice into the battery.

When I got back, plugged the Noco Genius G3500 back in. Set it into 'Regeneration / Slow Charge' mode and it's been running for 3 hours now at 75%. I'll leave it for a few more hours and it should be fully charged. Battery all ok. I'm sure systems have lost some information, I'll give it a run / test next week.

Thank you for all your comments. I'm glad I had the Sealey to kick start it into life !

Paul.

[Rusty Racer]

Good job Paul

[Astonished]

Well done

The smart chargers these days are excellent.

My old Passat R36 had sat for a couple of months (was “taken over” by my son after I got the RS4) as he’d gone overseas and it had done close to 200,000kms and was 7+ years old. The battery was showing absolutely zero. I stuck a c-tech charger on it and tried “regeneration” ... nothing. I gave it a second try and it came good, dragging it back from the dead. From there on I put the charger under the bonnet (in the drive) to give it a boost from time to time - i could shut the bonnet with the power lead sneaking out near the headlight corner and all good connecting it straight onto the engine bay connectors (battery also in boot like RS4).

The R36 went to my nephew and is still on the same battery.