Car won’t start - potentially battery.

[Jeetesh]

Was going to take my A2 out today and found the car won’t start. It’s only done about 10 miles in the last three months so that’s clearly not helped.

When I start the ignition I have dash lights, I get a millisecond of a slight turn of the starter before all goes dead, dash lights included.

If I put the ignition on and Colour DIS shows about 9.8v and then drops so my instant thought is battery. Tried jump leads (+ve first) however when connecting the -ve from my working car to the non working A2 (battery terminal as I don’t know where the earth in the boot is) same thing so assuming I’ve not connected the jump leads properly as I don’t show a higher voltage on colour DIS??

I’m assuming it’s the battery that needs replacing as the last time I drove it a month or so ago colour DIS was showing normal voltage but that’ll probably be the alternator. It did falter on start up the previous two times but did indeed start.

If it’s the battery what’s the consensus on a suitable replacement battery for the FSI or is there something else I should try before putting my hand in my pocket? If I’m not jump starting properly then please also let me know.

thanks in advanced.

 

[audifan]

Remove the battery from the car and charge it for 24 hours. Refit to car then have the battery load tested by a garage. If passes do not let it go flat again, if fails then replace with the correct capacity one from Tayna Batteries. As for which brand you chose that is up to you as everyone has their preferred brand.

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[Howey]

If battery good
Suspect engine earth?

 

[Jeetesh]

I’m going to try @audifan suggestion of battery charger first and if it turns out to be the battery then I’ll replace this. If this doesn’t cure it then I’ll check the earth strap behind the headlight.

 

[audifan]

Unfortunately a lead acid battery never recovers completely once it has gone flat. The more it goes flat the lower the charge it is able to accept. Pretty sure lockdown has had a terminal effect on a lot of car batteries not just fitted to A2s. That is why you need to get it load tested ( or health checked ) by a garage. Even if your alternator is very good if the battery will not accept the full charge you will be on a loser.

 

[Jeetesh]

Unfortunately a lead acid battery never recovers completely once it has gone flat. The more it goes flat the lower the charge it is able to accept. Pretty sure lockdown has had a terminal effect on a lot of car batteries not just fitted to A2s. That is why you need to get it load tested ( or health checked ) by a garage. Even if your alternator is very good if the battery will not accept the full charge you will be on a loser.

Noted, I’ll get hold of a charger and see what this does first and go from there. Any thoughts on lithium-ion batteries?

 

[audifan]

Personal opinion is great batteries but A2 was not designed to use them so stick with lead acids. Get a smart charger that controls the current to the battery.

 

[Jeetesh]

Personal opinion is great batteries but A2 was not designed to use them so stick with lead acids. Get a smart charger that controls the current to the battery.

Ok

 

[Robin_Cox]

I’m going to try @audifan suggestion of battery charger first and if it turns out to be the battery then I’ll replace this. If this doesn’t cure it then I’ll check the earth strap behind the headlight.

One thing worth noting - don't discount the benefit of cleaning the starter earth early in this process. I had three (normally) good batteries apparently give up on me in the run up to Christmas on all three A2s, so I bought VARTA replacements for the Tdis from Tayna (as well as a Ctek smart charger) and fitted them. One of those apparently gave up after about a week starting my main BHC car (which had been getting slower to start over the previous 10 days and then again once the new battery was fitted). I then cleaned the earth. Car restarted first time with a quick starter turnover and has never looked back. On the AUA car I never got round to swapping batteries - cleaning the earth resulted in the car starting first time despite not having been able to turn the engine over the day before. Colour DIS / ODB reader shows both batteries on 12V or slightly over at rest and 14.2V with the engine running, with minimal drop after cranking and startup. So I could have saved myself the cost of at least 2 batteries with some basic preventative maintenance (it took doing it for me to believe it though, now I am an earth evangelist!)

 

[Jeetesh]

Ok, noted.

My car is an FSI and one thing I’ve read on A2OC is that an earth problem leads to misfiring. It’s never (touch wood) misfired which leads me to believe that’s the battery.

I will look at this depending on the outcome of battery charging/replacement and report accordingly. That said I might do it anyway as general maintenance/upkeep.

thanks.

 

[VAG fool]

Aluminium oxide is a really good insulator!

 

[Jeetesh]

I’ve charged the battery, reinstalled and it started perfectly as if there wasn’t anything wrong.

I don’t own a multimeter so I checked with colour dis and was showing 12.6v which I think is normal, it started normally and whilst giving it an Italian tuneup it was showing 13.9v (normal so alternator seems fine). Switched it off and then checked and we have 12.6v from the battery.

Right now all seems fine however I’ll try this evening and then after a few days and if the voltage pre-ignition is lower than 12.6v I know it’s the battery.

thanks for the guidance, it’s very much appreciated and reinforces the value and contribution of members.

 

[johnyfartbox]

Unfortunately a lead acid battery never recovers completely once it has gone flat. The more it goes flat the lower the charge it is able to accept. Pretty sure lockdown has had a terminal effect on a lot of car batteries not just fitted to A2s. That is why you need to get it load tested ( or health checked ) by a garage. Even if your alternator is very good if the battery will not accept the full charge you will be on a loser.

Graham is bang on the money there.
I bought a brand new motor bike 5 years ago and within 12 months I left a dash cam plugged in and it completely flattened the battery, I managed to put some charge in it and it did eventually start the bike but every time I parked it in the garage I had to connect it to a optimizer charger or it would be flat within a few hours.
This week I have finally replaced it at a cost of £88.

 

[Jeetesh]

Agreed, I’ll see how it goes in the next week or two. My barometer is the 12.6v pre-ignition voltage, any downward variation and that load test and/or replacement battery is the next thing.

Thanks to @audifan for the link as the equivalent replacement is indeed £88 and that’s for the exact same Bosch battery I currently have. If it isn’t necessary and went flat just because my car has not been used for a prolonged period that’ll save me some cash.