Shankar

Hi,

Thinking of using my BatteryTender Jr on the RS3. Is there anything specific to watch out for? Are folks using an other product for keeping the battery topped up?

thanks
shankar

Nachos Libres

If you look at the comparison it says it will only maintain a car battery, but not charge. It is really made for smaller applications like motorcycles. I personally just bought the Battery Tender Plus.

uberwgn

CTEK.

morris39

Yes I use it on my S3. If battery voltage is down to 12.3-12.5, recharge will take about 2 hrs.If down to 12.1, then overnight (as far as I know). Also use it on my motorcycle. Ideal device as a trickle charger but probably would take too long to charge an almost fully discharged battery.

russbert

+1 on Battery Tender Plus as I own a couple of them!

gamegenie

Why is this needed in the first place?

Are Audi's batteries known to go bad quickly, and you are getting this to compensate for the car's shortcomings?

Nachos Libres

It's for doing work with VCDS and OBDEleven (where you typically need to have the ignition on without the engine running) or for when you are flashing the ECU or TCU (which again needs the ignition on without the engine running). Having the ignition on without the engine running can cause significant battery drain as many of the systems of the car are still running and putting strain on the battery system (and don't have an alternator charging them). You definitely don't want your battery to become discharged in the middle of flashing your ECU or TCU.

It's also used for when you need to leave the car for a long time (say a week or more). Batteries discharge over time, and if you leave a car long enough without starting it the battery will not have enough charge to start the engine. Tenders are typically used to keep the battery in good condition because discharging the battery causes wear on the battery, so if you are able to keep the battery charged it will typically last longer. I rarely will use the tender for this as my car usually doesn't sit longer than a couple of days or so before driving it but for some their S3/RS3 may be their weekend or once a month car.

morris39

Batteries sulphate i.e. lose capacity if undercharged or overcharged. If battery capacity falls below 50% (~12.2V) life is reduced somewhat. In cold weather if the car is only driven short distances voltage can drop to 12.2V if not used say for a couple of days. That is my experience. I have 3 vehicles (car RV, moto) which are used seasonally to some extent so I am used to checking battery voltage.
I have a CTEC and BT Jr. and they seem to work equally well on the car and bike. The S3 is my first Audi and it seems to have a bigger amp draw than my previous cars even though there is no apparent issue.The car talks to itself for about a minute or so after parking and maybe later when I am not there.Not enough to cause starting issues (cold/short trips) but volts drop down so I use the battery tender occasionally.

gamegenie

I also ask this question because my 2015 A3 is at the service center right now due to my A3 started slow cranking starting last month.

This year I moved really close to work (-5 min drive) where before my drive was 40-60 minutes from home to work.

I first reported this issue when I got 45K service (at 43K) last month but they only recharged my battery, despite the battery failing the inspection and approved a replacement.

I dropped it off this past Friday, so it's a wait and see.

russbert

FYI, I use my battery tender for long term sitting in garage (as mentioned previously) but also when I was learning / experimenting with the Virtual Cockpit and its myriad of settings and when loading 2,300+ songs into the Jukebox on the RS3.

Short trips are definitely harder on batteries but I hate them (short trips) due to moisture buildup in the oil. I remember reading it takes about 20+ minutes of driving to help reduce this. Comments?

Also, have you heard anything yet from the dealer?