Battery (engine battery) advise

Silver5urfer · Oct 2, 2018

Had a flat battery after 9 days camping in France, despite turning off courtesy lights by rear view mirror. I didn't realise that opening and closing doors would drain battery so much, I don't have electrical closing.
Borrowed a friends charger and charged it for 6 hours, then started OK.
Have now driven over 700 motorway (mainly) miles, stop/start seams to work OK.
Out of interest I put one of those digital voltmeters into lighter socket of slide out cup holder and only just getting 12.0V, (the leisure battery gives 12.7V).
Is my battery on its way out?
Any recommendations for replacement battery for 2013 Beach 140hp, RAC want £290 to fit a Bosch AGM battery.

jts46 · Oct 2, 2018

Try battery store

Max-Felix · Oct 2, 2018

Silver5urfer said:
Had a flat battery after 9 days camping in France, despite turning off courtesy lights by rear view mirror. I didn't realise that opening and closing doors would drain battery so much, I don't have electrical closing.
Borrowed a friends charger and charged it for 6 hours, then started OK.
Have now driven over 700 motorway (mainly) miles, stop/start seams to work OK.
Out of interest I put one of those digital voltmeters into lighter socket of slide out cup holder and only just getting 12.0V, (the leisure battery gives 12.7V).
Is my battery on its way out?
Any recommendations for replacement battery for 2013 Beach 140hp, RAC want £290 to fit a Bosch AGM battery.

When you took the reading what were the circumstances? ie was this after the failure to start or with any load on the battery etc? Also make sure the voltmeter is making good contact.

Fitting a battery takes minutes, I certainly would not be paying the RAC to fit one at that price! Just match up the spec exactly (ie physical size, amp hours and type) and buy from a decent specialist seller online or eBay would be my advice.

Alan Andrews · Oct 2, 2018

Try EuroCarParts. The Duracell batteries have a 5 year warranty, plus ECP always has a discount code available. They are all across the country so you'll not need to travel far to pick up a replacement. I can vouch for their no-quibble warranty. Just go to the website and type in your registration number to see available battery options.

VW Guru · Oct 2, 2018

Hi so if your going to replace your own battery that’s fine but please be aware your start stop will no longer work the new battery must be programmed to the vehicle so that the stop start will work so it’s not as easy as it seams just to replace the battery. Also a 6 hour charge is not enough to restore a battery to full capacity it must be trickle charged for at least 12 hours. The output from an alternator is to high and it will not recharge the battery to full capacity once it has discharged it will cause calcification of the battery. Battery and alternator technology has changed a lot and no longer works the way it used to.

Silver5urfer · Oct 6, 2018

Hi Max, this was taken using one of those digital voltmeters that you plug into the lighter socket. The van was parked up, nothing running. Voltage was only 12.0V. Had been parked overnight after driving 200 miles.

Sp0_0k · Oct 7, 2018

No idea why Vw does not charge main battery on a hookup but I would recommend a good practice of carrying a decent charger and hook the battery regularly for a good conditioning full charge. Especially when camping for a long time.
I've noticed the car battery normally reads 12.2-12.4v after driving.
I regularly charge a laptop from it drainin to 12v.

Loz · Oct 7, 2018

AGM batteries do not fair well if you let them get below 10.6 volts so if it was very flat as you say initially then it may be damaged and won’t recover.

Batterymegastore is a very competitive supplier, but as @Vw guru says, you still need to get the battery monitor adapted after the new battery is fitted, but you could leave that until your next service if not too far away, and ask your dealer to do then.

WelshGas · Oct 7, 2018

Sp0_0k said:
No idea why Vw does not charge main battery on a hookup but I would recommend a good practice of carrying a decent charger and hook the battery regularly for a good conditioning full charge. Especially when camping for a long time.
I've noticed the car battery normally reads 12.2-12.4v after driving.
I regularly charge a laptop from it drainin to 12v.

The Main engine battery is Trickle charged from the Mains Charger and this has been so since about 2010.
Although the Leisure Batteries can be fully charged from the Mains Charger, if flat, not so the Engine battery. Due to the Stop/Start, Regenerative Braking , etc of the Emissions package the Engine and Leisure Batteries can only be charged to about 80% capacity from the Smart Alternator technology.