[s-cars] Battery update, C4 A6

[Kent McLean]

(this bounced, so I'm trying again)

Lee Levitt wrote:
> Now, if I can figure out why my RNS-E is killing the battery in my 
> C5 A6, I'd be a happy camper!

My 20V200 TQA has a slow battery drain (kills the battery over 2-3 weeks).
I need to go through the debugging routine. If anyone wants to correct me 
on this, please do.

Finding a battery drain:

1. Disconnect the + cable at the battery.

2. Connect a DVM between the + terminal and the + cable. 

3. Set the DVM to measure milliamps (and don't try starting the car).

4. Note the amperage you are starting with. (If it is less than X ??? ma, there 
is no drain. The radio (memory) and alarm system? will produce a minor drain on 
the battery. We are looking for a bigger drain that kills the battery in a week 
or two.

5. Pull one fuse at a time. Note the change in amperage.

6. When you pull the fuse that makes the amperage approach 0, you've found the 
drain.

7. Replace that fuse and keep going; you may have a 2nd drain on the battery.

8. Determine which loads are protected by the fuse identified in step 6 (or 7). 

9. One at a time, remove each load to see which one is causing the drain.

10. Repair or replace the problem found in step 9.

Comments and corrections welcomed, especially the minimum value that is an 
acceptible drain.

-- --
Kent McLean
'99 A4 Avant
'91 200 20V Avant #3
'94 100 Avant, sold
'91 200 20V Avant #2, up in smoke #2
'91 200 20V Avant #1, recycled
'89 200 10V sedan, up in smoke