Battery help
 

As some of you know my D3 sees very little use these days.

This evening the car alarm started sounding on the Audi, so I unlocked the car and got but no interior lights. Key in ignition and nothing, had to use emergency release to get key out.

Obviously the battery is flat, so out came the jump leads and I got my diesel Volvo into position to jump start the Audi. I hooked the + terminal directly to the battery and the - side to the battery manager and all the lights came on at which point the Audi successfully started.

She has been outside idling now for nearly an hour, but the battery status on the MMI still only has one bar.

The worrying thing is I connected a multimeter to the battery before doing anything and it said way less than 10V. I am guessing the battery may have been to deeply discharged to be recoverable, and may end up needing a new battery. I did this because my battery charger would not start to charge the battery.

With the engine running the volt meter is showing 14V

I am just heading out to buy some more petrol, the Audi does not have much left in it so I can leave it running.

Well after 2 hours running and a short drive the battery voltage with engine off was 12.4 volts, battery meter still stuck on 10%, lets see what tomorrow brings.

Interesting observation, the parking sensors have started working again.

Manny,

A good battery should read 12.6v after removal of residual charge. After charging battery fully, the rule of thumb used to be leave headlights on for 2 minutes to remove residual charge then check, but that was when they had standard 55w bulbs - not sure what load halogen or LED would give though.

If <12.2v, you need a new one, if >12.2v and <12.6v, try a bit of discharge and then fully charge again, then do check as above, but in reality in 99% of cases with modern batteries, it will be dead.

You would be amazed at the spurious messages I used to get out of my Jags when battery was on the way out.

With c. 14v charging voltage, sounds like your charging circuit is good though.

Mark.

Yup, I've been there so many times when batteries get "marginal", wasting time and effort trying to tickle them back to life and eventually failing miserably.
Just bite the bullet and get a new one. +++

New batteries are quite expensive so to try makes sense but be prepared that it has fallen off it's perch.
Problem with a lot of modern chargers is that they will not charge a flat battery. They are too clever and think that if the batterey voltage is very low then iot is dead so dangerous to charge at the high current it seems to need.
I don't want to get all technical, just be careful with intelligent chargers.

I've got an old-school Halfords charger that has got me out of a hole more than once as it doesn't care! +++

Well she started ok after being left overnight, so I left her running for.a bit and drove it work. I'll do 350 miles that s weekend. Was going to use the volvo but will take the Audi instead.

I'm sure the old girl will be grateful of the attention.

I did over 350 miles last weekend without incident in the D3, battery holding up well. Now she is back to her hardly being used mode will see how well it copes. I took her on a 40 mile round trip last Thursday.

I really need to sell this car, she needs more attention than I can currently afford to give her as I limp from one temporary low paid job to another. She is way overdue a service and cambelt change (both on time and not miles).