Battery charging for stop-start engine question

[jhn34225]

Hi

Polo 1 litre petrol automatic 2021

The battery doesn't currently need to be charged but for future reference I would like to know where to connect the minus connector from the charger. I have a CTEK MXS 5.0 and I understand that the minus connector shouldn't be connected to the minus battery terminal on stop start batteries.

On my old Golf there was a notice on the battery explaining where to connect but on my new Polo there is no notice.

Any advice appreciated, thanks.

[iichel]

Chassis or minus strap on the engine

[RUM4MO]

As above, there should be a suitable chassis bonding point near the battery -VE, on the earlier 6C Polo there is a domed nut which I use with my CTEK MSX 5.0, on that car the domed nut is painted, so I have cleaned the paint off some of the "peaks" and keep these areas covered in petroleum jelly to hold back corrosion. Maybe your version of Polo has a plated tag that you can clip the croc clips to - at that point.

[jhn34225]

Thanks for the info. Please see the attached photo, would either of the areas circled in red be suitable? Thanks.

[ho8882000]

I use this as the negative terminal when charging the battery:
(Note: My Polo built by the factory without Start & Stop System.)

IMG_20210817_130256.jpg (3.1 MiB) Viewed 5815 times

[RUM4MO]

I use this as the negative terminal when charging the battery:
(Note: My Polo built by the factory without Start & Stop System.)

Good to see that VW are fitting that "-VE" or chassis point to cars, perfect for charging and jump starting - which will be why they fitted it.

Edit:- I looks like from both pictures that access to the local earth or chassis point that the battery -VE connects to, is not easily accessed - so providing that "service" chassis stud was essential.

[RUM4MO]

Thanks for the info. Please see the attached photo, would either of the areas circled in red be suitable? Thanks.

No, the metal hold down clamp for the battery screws into a metal captive nut in a plastic tray - so no chassis connection.

The other point does not look too good either, does your car not have the large -VE chassis "service" stud?

[jhn34225]

Thanks for all of your help, yes the car has a service stud so I'll use that.

[Johntheo1]

Be interesting to see how long these batteries will last with the combination of start/stop and smart alternator charging. I monitored mine (Jan 2018) yesterday via a M.meter in the inside power jack and under normal driving/idling conditions it never charges any higher than 13.2/13.5 volts but on on overrun will rise to 14.8 and very occasionally 15 volt, presumably this combination will result in a decade or so of battery life but I doubt that very much.
I use the start/stop selectively but I notice that the voltage was only 12.2/12.4 volts with engine off, start/stop enabled but with absolutely no electrical auxiliaries in use. I have a 3.8 A smart trickle charger (never used) so someday I might connect it up and see how long it takes to get my battery up to peak charge. All my older VW batteries lasted > 10 years and were only replaced as a precautionary measure, they all charged "stupidly" at 14.3/14.4 volts.

[Johntheo1]

Be interesting to see how long these batteries will last with the combination of start/stop and smart alternator charging. I monitored mine (Jan 2018) yesterday via a M.meter in the inside power jack and under normal driving/idling conditions it never charges any higher than 12.8/13.5 volts but on on overrun will rise to 14.8 and very occasionally 15 volt, presumably this combination will result in a decade or so of battery life but I doubt that very much.
I use the start/stop selectively but I notice that the voltage was only 12.2/12.4 volts with engine off, start/stop enabled but with absolutely no electrical auxiliaries in use. I have a 3.8 A smart trickle charger (never used) so someday I might connect it up and see how long it takes to get my battery up to peak charge. All my older VW batteries lasted > 10 years and were only replaced as a precautionary measure, they all charged "stupidly" at 14.3/14.4 volts.

[SRGTD]

Be interesting to see how long these batteries will last with the combination of start/stop and smart alternator charging. I monitored mine (Jan 2018) yesterday via a M.meter in the inside power jack and under normal driving/idling conditions it never charges any higher than 13.2/13.5 volts but on on overrun will rise to 14.8 and very occasionally 15 volt, presumably this combination will result in a decade or so of battery life but I doubt that very much.
I use the start/stop selectively but I notice that the voltage was only 12.2/12.4 volts with engine off, start/stop enabled but with absolutely no electrical auxiliaries in use. I have a 3.8 A smart trickle charger (never used) so someday I might connect it up and see how long it takes to get my battery up to peak charge. All my older VW batteries lasted > 10 years and were only replaced as a precautionary measure, they all charged "stupidly" at 14.3/14.4 volts.

Quite a few owners over on golfgtiforum.co.uk have needed to replace the battery in their Golfs at around 4-5 years old; some have replaced sooner.

[RUM4MO]

@Johntheo1, quote"All my older VW batteries lasted > 10 years and were only replaced as a precautionary measure, they all charged "stupidly" at 14.3/14.4 volts."

I can relate to that, I have a new AGM battery in my garage waiting to put into my 2011 Audi S4 whose original battery looks to be in very good condition, but ---------, so I'll swop batteries soon, just as a precautionary measure! That car sleeps most of its life in the garage connected to a CTEK MSX 5.0, and has done for maybe 8 years.

[Andy Beats]

Two years of very low mileage commuting (7 miles per day) in my 95Tsi, no stop/start or battery problems.
Aside from commuting it was only ever used around town, it never got a long run in the whole two years.

[Harrihealey02]

My Polo battery is starting to degrade, if engine off and auxiliary power still on for only 5 mins the engine struggled to start. I have accidentally ran the battery dead at least two times in the past with auxiliary power and engine off which May have reduced the battery life somewhere.

[RUM4MO]

That battery will be an EFB, so maybe get it tested to see "how it looks" if it is confirmed as being "well used/running out of life" - then head for Tayna batteries for a suitable replacement before you are let down in the colder weather. As it stands, if that car is similar wrt the battery tray, you can not fit a slightly bigger battery - so choose a Varta or Bosch etc same size as fitted currently, reg'ng the new battery to the car can be done with VCDS etc or even Carista and just changing the serial number by one unit so that the car knows right away that it has had a battery replacement - doing that will optimise the battery's life quicker/better than not reg'ng that new battery.