Battery dying?

[AdamD]

See this way of checking the state of charge of the battery without a voltage meter:

Battery State of Charge (SOC)

[The_Hawk]

Batteries get a much harder life in winter because of a few factors. It's cold so they don't work as well (although heat soak largely deal with that), but it's also darker (and wetter at the moment too) so you're running lights and wipers far more often than in summer.

I have a simple sign that my battery might need a top up... the power windows. I find that the auto up function gets a little spotty when the battery is a little low. It's like it doesn't quite have the voltage (and torque) to get up and it senses a jam so goes down again in what should be normal operation. Charging the battery and everything moves quicker and cleanly again. Funnily enough I tend to notice these things in summer more than winter since now it's cold I don't have the windows down nearly as much

It's just expensive bling mate, leads to the dark side it does, resist you must

Oh I understand that, but I like shiny things... and data. That little line showing history intrigues me, especially given my usage patterns it would be very interesting to see what its reporting over time. I would actually like two of them so I could run them in both cars and see how they compare given very different day to day usage. If anyone wants to buy them for me I'm willing to test them and report back

[Jondalar]

Thanks for the very helpful replies. I do have a multimeter but I'm not sure what voltages should be apart from around 12. I'll try the tripmeter function. Helpfully we'll soon be away for 4 weeks and I'm pretty sure sitting that long will be enough for the battery to fail.

Cheers,
Karl

[Eaglehawk]

3 years old (and 2 weeks) MY13 Golf 110TDI. Battery died yesterday.

Was hard to start in -3 degree temp in the morning. Drove fine during the day (started twice). Arrived home, then went to pick up the kids..."Low Battery"...

NRMA Battery replacement, $352...

[brad]

3 years old (and 2 weeks) MY13 Golf 110TDI. Battery died yesterday.

Was hard to start in -3 degree temp in the morning. Drove fine during the day (started twice). Arrived home, then went to pick up the kids..."Low Battery"...

NRMA Battery replacement, $352...

Wow! They saw you coming... Not good batteries either.

[Eaglehawk]

Wow! They saw you coming... Not good batteries either.

Which one? The OEM or the NRMA one =)

Options were limited, kids needed transport and the 25 mins wait time was worth the $1/minute charge child care would cost.

[brad]

Which one? The OEM or the NRMA one =)

Options were limited, kids needed transport and the 25 mins wait time was worth the $1/minute charge child care would cost.

The NRMA unit. Dad's had a few of them (NRMA member for 70 years and thinks they are still the same company that they started as) and they usually die about 3 months after the warranty is over.
I only changed an NRMA battery out of his car 3 weeks back and it wasn't a great battery.

Yes, sometimes you just have to go with the immediately available option. I once paid $200/night for accomodation in a Greek town where a room usually went for $60. The incoming ferry died at the wharf and there was twice as many people as beds. Pay $200 or sleep in the gutter with some football hooligans - it wasn't a hard choice.

[Jondalar]

See this way of checking the state of charge of the battery without a voltage meter:

www.vwwatercooled.com.au/forums/f197/battery-state-charge-soc-93476.html

Just checked the battery SOC and showed 70% but the car is slow cranking and doesn't fire very quickly compared to how it used to. It's also not shutting down the engine when stopped at traffic lights etc. Anyone know what SOC is shown when the battery is poor? Or what else can cause slower cranking and not firing immediately. When returning from a 3 week trip it cranked for about 30 seconds before the diesel fired, we allowed the glow plug indicator to go out before cranking too btw.

Cheers,
Karl

[h100vw]

I'd get a ctek charger and do a recondition on the battery. My guess for not stop starting is the car knows the battery isn't up to it and has cut the feature. Unless you have switched it off.

Repco were doing mega deals on ctek last weekend. I got one for $99.

Gavin

[DV52]

^ ^^^ hm........ there's a couple of things that are worth noting about batteries on mk7 vehicles -they are not like the batteries that were used in cars in "the old-days" - alas:

First , the veracity of the SOC measurement is entirely dependent on how well the car owner has respected the battery monitor control module (J367). It sits just next-to the negative battery terminal and its job is to translate the flow of electrical current to/from the battery to the car's analogue-to-digital converters. The destination of the data stream from J367 is initially the CAN Gateway (address hex09) and eventually the data is used to calculate what VW calls "System Voltage" (which is very different to Battery Voltage). Most (all?) of the decisions that the various control modules in a mk7 make about the car's rail-voltage is based on the calculated "System Voltage", not battery voltage, so it's important to ensure that this calculation is done correctly FOR THE ENTIRE LIFE OF THE BATTERY!

Stuff like charging the battery by directly placing the negative charger lead on the negative battery terminal is a definite no-no as this practice by-passes J367. The result is that the digital table about the car's SOC is incorrect! Another no-no is failing to tell the CAN Gateway (and J367) that the old battery has been replaced. This causes the calculation of System Voltage to use the obsolete history file from the discarded battery!

So, if you do change the battery, make sure that you follow the correct procedure for recording the new battery specifications in the control module tables (there are 3 x adaptation channels that need to be updated). If you don't buy a BEM replacement battery, at the very least you should change the serial number of the battery in the CAN gateway (which is UDS type for a mk7).

Finally, the other aspect of a mk7 battery that is worth noting (IMO) is the types of OEM battery that VW uses, which are enhanced flooded battery (EFB battery) and absorbent glass mat battery (AGM battery). Both of these types are superior to conventional batteries and AGM is superior to EFB. These batteries are matched to the needs of the car's features - such as Start Stop. Sure you could try a cheaper conventional battery, but in the long term, the economics likely would be questionable -IMO.

Don