UK-POLOS.NET - THE VW Polo Forum

I’ve had the Polo for 2 years 5 months so far and lately the battery seems to be getting weaker. This morning it struggled to start, and over the last few weeks I've noticed that leaving the ignition on and engine off for only 5 minutes causes the battery to struggle starting the car. Is the battery classedas a wear item or is it covered under the 3 year warranty?

Harrihealey02 wrote: ↑Fri Aug 27, 2021 2:18 pm I’ve had the Polo for 2 years 5 months so far and lately the battery seems to be getting weaker. This morning it struggled to start, and over the last few weeks I've noticed that leaving the ignition on and engine off for only 5 minutes causes the battery to struggle starting the car. Is the battery classedas a wear item or is it covered under the 3 year warranty?

I've had a Golf battery replaced under warranty before - you should be fine.

Seems a very short lifespan for a battery, they should last a damned sight longer than that.
Maybe more investigation needed, maybe the battery is fine but it's not getting enough charge from the alternator.
So you'd have the same issue with a new one too.

Andy Beats wrote: ↑Mon Aug 30, 2021 11:29 am Seems a very short lifespan for a battery, they should last a damned sight longer than that.
Maybe more investigation needed, maybe the battery is fine but it's not getting enough charge from the alternator.
So you'd have the same issue with a new one too.

I think Covid inactivity has wrecked many batteries meant to last 5 years, but only lasting 2.

My wife's Polo is the same age but no problems even though most runs only 3/7 miles/day, these have a smart charging system which only give around 12.8vV to 13.5ish V while driving and will only allow full charging of up to 15V on overrun with foot completely off the acc pedal, I monitored it via the power point (cigarette lighter) in the car with a multimeter, whether this will give the same very long battery life of > 10 years of all my former VWs which all charged at a constant 14.3V even when idling, remains to be seen, I wouldn't hold my breath.

VW said that the battery is covered under warranty however the next date was a week from when I called them for it to be looked into and they said they would have it for 2-3 days. Chose to pay for it myself £140 Halfords and it comes with a 5 year warranty and is a newer construction AGM rather than EFB or something similar. They plugged in a device which changes the car battery status to the AGM type so not sure how much voltage will be provided to it.

Good to see that Halford actually recode the car's BMS to reflect the change of battery and the battery technology.

Really, as has been said, or implied, unless you now use the car more and on reasonable length journeys, you will be back to needing a battery sooner than you could be, can you connect a smart battery charger to your car if you are not using it frequently and on reasonable length journeys?

If you could and did do that, your new battery should live for many years.

Edited to change "Real" into "Really".

I’ve always driven the car on long journeys, sometimes in distance but mostly in time as traffic etc. There was a few occasions where the battery was left on and it ran out of charge due to the wipers being left on etc. I’m going to be more careful with the new battery snd keep the engine on when I’m using auxiliary power for any length of time when parked.

On our Polo, while stopped, the wipers go to intermittent wipe whether start/stop enabled or not, I imagine the dipped beams would sap a lot more battery energy with engine stopped. Before the advent of the alternator smart charging, any of the numerous VWs I owned would maintain 14 to 14.2V while idling even with dipped beams and heated rear screen on, hence, IMO the > 10 year battery life even in the Polos doing very short runs for most of their lives, I replaced the battery after ~ 12 years purely as a precaution in a 2005 9N model, still in the family. I have VCDS and will trend the voltage sometime but judging by my brief M.meter readings then the battery cannot be kept on full charge with the smart charging, however lets see what happens.

One thing I could never figure out is that with all this constant > 14V charging that I very rarely had to top up the old type lead acid batteries.

The newer "old lead acid" batteries had the materials changed slightly to reduce gassing.

The current way of doing things wrt car batteries is, never aim to keep them fully charged as that is wasteful and leads to higher emissions, what is done, is to maintain a lower charge level, but one that should never compromise the ability to restart the car engine, by doing that, there is normally enough "charge free space" in the car battery to harvest otherwise wasted energy, at times like when on the overrun to top up the battery "free". This has all been chatted about in the past I think.

Stop/start technology & smart charging systems have been out for a considerable time now, is there any feed back from anywhere/anyone re battery longevity I wonder, I know a few people with BMWs and at least 3 of them seem only to get ~ 3 to 4 years out of their batteries even though doing reasonably long trips, these ones that I know of do not have stop/start, so perhaps a bit of "overcharging" at 14V or so with a long battery life is better environmentally than replacement every 3 to 4 years if this indeed is the trend.

I have noticed in the last few days of my last battery I was getting low battery warning messages, if it could detect low voltage it was too late. I wonder if there’s a way to change the voltage monitor to flag up when it gets to a higher ‘low’ value so I can start the engine without it being that low it won’t crank over. Must be a setting in VCDS I can configure.

There probably is.
If you have VCDS then I would monitor your voltage with A/C & HRS (heated rear screen) on and also plot the engine RPM on the same graph, that will give you a good idea of how your charging system is performing.

A "snapshot" of what's happening can be done far quicker with a multimeter plugged into the power point and set to 20V DC, bring someone with you to monitor it as you don't want to end up in the ditch while watching it!.
Just connect up two connector blocks to the plug lead and stick the two probes from the M.meter into them, the polarity does'nt matter as it will just give a minus reading if reversed.

Did a relatively long (30 miles, each way) run yesterday and the M.meter read 13.0V to 13.4V "under way" or idling, and 14.2V to 14.6V on the overrun both with no auxiliaries on or dipped beams + HRS on (don't have AC), quite satisfactory IMO.

This is the battery state of our Jan.2018 Polo, 8121 miles, all short runs in daylight usually, stop/start normally disabled and always disabled by my wife.
I think the BMS maintains 80% SOC.

Address 19: CAN Gateway (2Q0 909 901 )

13:15:22
IDE00019 Voltage terminal 30 12.3 V
IDE01834 Battery voltage 12.336 V
IDE01836 Battery current -4.920 A
IDE01838 Battery temperature 21 °C
IDE01839 Battery charge level 82 %
IDE01841 Battery internal resistance 6.6 mOhm
IDE01842 Usable battery charge 37 Ah
IDE01948 Battery internal resistance not normed 5.4 mOhm

And some more info whatever it means.

Address 19: CAN Gateway (2Q0 909 901 )

17:39:50

IDE03011-MAS04054 Number of requested start processes-Consumer/component current too high 0

IDE03256-MAS06105 Battery adaptation-Rated battery capacity 59 Ah

IDE03256-MAS06106 Battery adaptation-Battery technology EFB

IDE03256-MAS06107 Battery adaptation-Battery manufacturer JCB

IDE03256-MAS06108 Battery adaptation-Battery Serial Number 1111111111

IDE03588-MAS05683 System malfunctions for active participants start/stop-Battery fault 0

IDE08347 adapted battery capacity 84 Ah

News flash: For the first time in 58 years without using a charger on any of my cars I connected my (smart) charger to the Polo battery and within 10 minutes it c/o to trickle charge which confirms more or less that the battery is indeed fully charged and the 82% indicated battery charge level (VCDS) is to be expected with a nearly 3 year old battery so I will monitor it every few months from now on and post findings.