Battery problem?

[peterb]

I switched from RNS-D to E on my RS6 and have just recently attached the alarm wire to DWA-GND of the RNS-E to force the shutdown of the peripherals.

As far as I can determine, my PhatBox and amps power down when I lock the car, and power back up when I unlock. I didn't take any specific precautions with regard to an alarm connection when I swapped to the RNS-E. I had assumed that the arm/disarm information was being carried on the CAN bus. As far as I can remember, the Kufatec adapter didn't involve the 26-pin connector.

Should I worry about connecting the ATA earth (pin 1 of 26-pin connector) to DWA-GND on the RNS-E?

[mikeyquattro]

Have you checked the levels?
Had to replace my battery last year as the levels dropped and fried the plates.
I was getting similar problems where it woudl start fine when 'warm', but if left overnight it stuggled to turn over

[Dippy]

Well it's interesting about the SatNav and Phatbox, but I'm pretty sure that they are OK. Before I installed that SatNav+ I had the OEM Symphony with BOSE, so my SatNav+ install was a fairly simple swap. The alarm wiring should already be done from the factory.

I've also monitored the Phatbox and am sure it powers itself down. However indeed I am not 100% sure so in one way I'm glad to have the dealer to a current test.

However I actually think I will be wasting my money for the diagnosis. On Tuesday, having driven to Kwik-Fit and then the Audi dealer, the battery was charged up enough to start the engine after each visit. By the time I got home, it should have been more charged (had a short run on the motorway too). I put the car in the garage and disconnected the battery. It had about 12.5 volts o/c, and was only a fraction less before I disconnected it.

This morning I rechecked the o/c voltage. It was now 10.5 volts, and the car wouldn't start. It needed to be jumped again for the dealer to take it away.

So with the battery not holding charge whilst disconnected, it must have a fault. I was almost tempted to cancel the booking and get a new battery, but with all this discussion about if I have a drain or not due to my ICE, I feel better getting it diagnosed. Of course if the result of that diagnosis is that I need a new battery and the electrical system is fine, then I will feel a bit ashamed

[craigyb]

Should I worry about connecting the ATA earth (pin 1 of 26-pin connector) to DWA-GND on the RNS-E?

All concert/symphony to RNS-E upgrades should carry that wire. Alarm to DWA-GND, it comes from J285 central convenience. I know the Kufatec RNS-D to E adaptors don't carry it, but the A4/A3 symphony ones do. I looked it up on ELSAWIN and it is something I will be making sure all future installations are fitted with when doing RNS-D to E.

If you look at a symphony in an A6, it has the pin wired, then look at the RNS-D and the same pin goes to pin 1 of connector 26. So I thought it would make sense to add it in. I could be wrong, but pin 16 of the power connector on the RNS-E now shuts down immediately when the central locking is activated, not 20 mins later. Maybe the CD changer will be as well, just a thought

I'm not saying anyone should have to do this, I'm just going to make sure it is done in the future on any of my installs.

Craig

[peterb]

Well, after posting this morning I went out and checked. With the cover off the boot locker I can see the PB power up withing 10 seconds of unlocking (not even opening a door). When I lock, the PB powers down again within 10 seconds.
Therefore, I'm fairly convinced that the connection is not required (at least not on a 2002+ C5).

[peterb]

This morning I rechecked the o/c voltage. It was now 10.5 volts, and the car wouldn't start. It needed to be jumped again for the dealer to take it away.

Well, it seems that the battery is self-discharging, so either it was faulty, or has been damaged. I wouldn't expect a one (or two) off deep discharge to make it quite so bad. Mine has been pretty well discharged on a few occasions and still holds charge for three weeks.

[Dippy]

I have the results of the Dealer's diagnosis and the news is mixed:

The battery is indeed dead as I expected. However in addition they found some excessive current drain. Not from the SatNav, and not from the Phatbox. No - from the instrument cluster! Apparently it should be no more than 70mA idle and mine is 120mA.

Fortunately my cluster is special order only so the Dealer can't get one (if I replace it I'll be talking to VAG-parts). However they are honest and say that this extra drain would only be a problem if the car is unused for several weeks. I suppose the extra 50mA uses about 8.5Ah of the battery's 70Ah every week so indeed that might be a problem. Maybe I can take out a fuse to drop the current when I go on holiday? Apart from the clock, I can't see any issue with powering down the cluster.

So I'm about 150 quid lighter vs the minimum 50 quid if I had replaced the battery myself. I'm not too bothered because the info about the cluster is useful.

However I'm not too pleased with Kwik-Fit's battery testing!

P.S. I asked if they could put a bigger battery in (e.g. from the RS4?), but they declined saying that would strain the alternator. True or BS?

[tartan_rob]

BS: The alternator will not try and keep trying to recharge the battery to its max it will simply replace the power that it can, if anything it is actually better as the alternator will always produce more power than running all the cars systems can use, so convienently you are giving it a dirty big hole to store the over capacity instead of trying to cram power into a hole that is already full...

I have been running 120amp/hr for approx 2 years now with no problem and all my systems run well (famous last words...!)

The only way to test the battery properly is to do a drop test, a special tool is required to do that...I'm surprised if Kwik-Fit got it that wrong....

[Nige_RS4]

Dippy, I thought the sat nav & phatbox were both intergrated into the CAN-bus wiring, which in dealer speak probably means the dash - just a thought? My experiences with main dealers over the years are not suitable for public forums. I will put money on you knowing more about your cars electrics than they do if you wired up your sat nav - they'll tell you it's not possible!

Nige.

[TWH]

Tartan Rob. Do you have a number or a web address for Batteries Direct. I tried a search, but didn't come up with anywhere that did car batteries of the same name. The 120amp/hr sounds like a good plan.

[tartan_rob]

I think I used Bristol Batteries (they have numerous locations, http://www.bristolbatteries.com) - there are other dealers/battery makers around the place, check out battery manufacturer/distributor in the phone book is these are not close etc.

[peterb]

P.S. I asked if they could put a bigger battery in (e.g. from the RS4?), but they declined saying that would strain the alternator. True or BS?

BS!

[peterb]

Dippy, I thought the sat nav & phatbox were both intergrated into the CAN-bus wiring, which in dealer speak probably means the dash - just a thought?

The SatNav is connected (via the TMC module) to the CAN bus. However, there is no current drain through that route.

I would still say that if you experience the sound drop-out and flickering display problems when using the PhatBox, there is the potential for occasional current drain.

[PhilT]

I've always use Varta - http://www.varta-automotive.com/eng/ind ... ?anzeige=5

[Dippy]

They fitted a Varta. It's slightly bigger (72Ah vs 70Ah). I also got the current wrong it's 110mA. Anyway, I'll have to wait and see what happens next time I leave the car standing for 2 weeks before bothering doing anything more.

Peter, I do hear an occasional gap in the music, but hadn't noticed any fickering display problems. Can you expand on that?