981 battery life

[TrackNutz]

WG said:

Having a trickle charger connected whenever the car is not in use for several days is no doubt beneficial. I have never bought a new battery for a Porsche in 30 years ! My last 2 vehicles were sold at 9 year old (996 Turbo) and 8 year old (987 Spyder) and both were on their original factory batteries ! Charger connected whenever cars were not used for more than 3 or 4 days.

A related question, I have been using a Porsche branded charger of 2004 vintage but am getting a new 718 GTS in January. Would you advise getting one of the new - more sophisticated - chargers such as a CTEK or Porsche branded ?

Yes, I'd highly recommend a new CTEK for your 718.

[TrackNutz]

curious2 said:

Interested in the comment above about not connecting charger directly to negative terminal. Ctek instructions say connect direct to battery terminals. What’s the issue with doing this on a 991.2 ?
Thanks

The issue is that it bypasses the battery sensor. Have a look at the two pin connector on a small black block at the negative terminal. This is the sensor.

The correct location is the wiper motor bracket. There is a small negative terminal symbol next to the bolt post on the bracket.

[DJMC]

WG said:

Having a trickle charger connected whenever the car is not in use for several days is no doubt beneficial. I have never bought a new battery for a Porsche in 30 years ! My last 2 vehicles were sold at 9 year old (996 Turbo) and 8 year old (987 Spyder) and both were on their original factory batteries ! Charger connected whenever cars were not used for more than 3 or 4 days.

A related question, I have been using a Porsche branded charger of 2004 vintage but am getting a new 718 GTS in January. Would you advise getting one of the new - more sophisticated - chargers such as a CTEK or Porsche branded ?

Does your 2004 model look like a CTEK unit re-branded? I phoned my OPC yesterday and they offered a "Charge-o-mat at £94.99 which I believe is a re-branded CTEK 3.6 or 3.8. The general consensus seems to be to get the CTEK MXS 5.0. I need to run this from the rear of my garage, through the door, into the armrest 12v socket (which I think is the only one in my 2014 981 which knows if you're charging by it so doesn't switch off with a charger connected - at least that's what the OPC told me).

I found the necessary items, including an extension cable, cheapest here:

https://www.amazon.co.uk/dp/B01MZZ6T5F/_encoding=U...

https://www.amazon.co.uk/dp/B00ADIHUVG/_encoding=U...

My OPC says it's fine to run the cable through the door as the door seals will give and not damage it.

The 5.0 manual has a flow chart of the different "modes"...



...and then describes them...



NB: Manual here: https://www.ctek.com/storage/ma/b343d2275859476796...

So, for my 3 1/2 year old battery, I guess I just plug the charger in and it gets to work BUT I have to select some options...




Which do I choose, AGM or RECOND? There's further detail in the manual...



Without guessing what battery type, I guess I need to check the battery itself which will tell me which of these programs to use? Is that correct?

Thanks for any help.

[anonymous-user]

^ You want AGM and Normal; the two middle lights. The unit will default to that selection when your turn it on. Your OPC is correct about the cable going through the bottom door seal. If you open the window with the cable thus trapped you will find you can reach down, grab it and it will slide side-to-side with minimal pressure so no damage being done.

[DJMC]

Hang On said:

^ You want AGM and Normal; the two middle lights. The unit will default to that selection when your turn it on. Your OPC is correct about the cable going through the bottom door seal. If you open the window with the cable thus trapped you will find you can reach down, grab it and it will slide side-to-side with minimal pressure so no damage being done.

Thanks. I've never heard the term "AGM" before (I know, I haven't LIVED!).

Now I know more: http://www.driverstechnology.co.uk/car-batteries.h...

I take it the 981 has only used AGM type batteries? If I want to double check, will I find "AGM" printed on the battery somewhere, or some other cypher?

[anonymous-user]

DJMC said:

Thanks. I've never heard the term "AGM" before (I know, I haven't LIVED!).

Now I know more: http://www.driverstechnology.co.uk/car-batteries.h...

I take it the 981 has only used AGM type batteries? If I want to double check, will I find "AGM" printed on the battery somewhere, or some other cypher?

I don't think it will actually say on the battery but if you note the battery code and search for replacements on design911 or similar the description will tell you for certain.

(I'd be surprised if the 981 didn't need an AGM battery though. If it has start-stop the oem battery will be agm.)

[TrackNutz]

Yes it will say AGM on the roof of the battery and yes, all 981 onwards have AGM's.

[DJMC]

TrackNutz said:

Yes it will say AGM on the roof of the battery and yes, all 981 onwards have AGM's.

Thanks. I was also unaware a battery conditioner could do so much to enhance the performance and /or life of a battery.

I wonder if it's true? Time will tell...

[SkinnyPete]

Thanks for the informative posts.

No I didn’t use the negative on the wiper post I did it straight onto the battery, to add to this mishap does it matter that my CTEK 3.8 does not have an AGM mode?

You say the gateway needs to know it’s a new battery in order to calculate ageing, charge strategies, charge level, condition etc. but if I replace it with a like for like battery then isn’t it simply a case of resetting it all to start from scratch, rather than changing anything in the parameters? In which case the detriment of not getting it coded will be minimal?

I’m also interested in the fact that some people have got low voltage warnings and I haven’t.

[Bennachie]

The snowflake setting is AGM

[TrackNutz]

You still need to have the new battery coded even if it's like for like.

Coding most importantly resets ageing (or life) to 100%. For example, if the battery manager was struggling to recover a battery that had dropped below 12.5v for a very long time, you'll see the voltage in the instrument cluster at around 15-16v. The Gateway values are (for example) state of charge @ 50%, ageing at 40% and condition @ 45%. Below 75% SOC the start stop will also not work.

You then fit a new battery but don't code it. The calculated amp throughput that the manger thinks the battery needs to recover it is still the same. So it charges with a high voltage and high amperage (981 alternators are duty cycle driven and can adjust voltage and amps independently with a variable internal resistance). So your instrument cluster is still showing 15-16v. Your start stop still doesn't work and the new battery will take a battering.

Now let's code the new battery in, all values are set to 100%, the alternator load is now minimal, the instrument cluster shows 12.8v with the engine running and start stop is happy again.

A massive difference. Plus the new battery gets a full life expectancy.

Imagine the battery manager as a librarian, it monitors every amp that's checked out and tries to ensure it's booked back in.

It does this even when the car is switch off and monitors the battery sensor to see if you're trickle charging and measures amp throughput, then adds this to the battery profile/condition. A new battery will want for very little so the charge strategy is totally different.

The actual values in the Gateway can show how many amps were used whilst the car was locked, what caused the car to wake up if anything, how much charge the battery had during its recent drive cycles, what causes the start stop to disable, etc.

If even logs how many drives you do between 0-3 miles, 3-6 miles, 6-9 miles, 10+ miles to build a charge profile. It also logs the time the engine is run for throughout its life in 0-3 mins, 3-6 mins, etc.

It's very very clever and hence the reason an OPC is far from ripping a customer off when they state you need your battery coded.

[SkinnyPete]

Brilliant post thank you.

So what are the consequences of me not using the trickle charger correctly? I did use the snowflake mode because its cold outside but I didn't use the correct negative terminal, my CTEK wires aren't actually long enough to reach both terminals so I will need to look at this.

Lastly why is a battery now so complicated? Is it purely for fuel saving, e.g. the more the gateway knows about the battery then the less dependency on the alternator and therefore the lower the fuel consumption?

Thank you.

[gtsralph]

TrackNutz said:

You still need to have the new battery coded even if it's like for like.

Coding most importantly resets ageing (or life) to 100%. For example, if the battery manager was struggling to recover a battery that had dropped below 12.5v for a very long time, you'll see the voltage in the instrument cluster at around 15-16v. The Gateway values are (for example) state of charge @ 50%, ageing at 40% and condition @ 45%. Below 75% SOC the start stop will also not work.

You then fit a new battery but don't code it. The calculated amp throughput that the manger thinks the battery needs to recover it is still the same. So it charges with a high voltage and high amperage (981 alternators are duty cycle driven and can adjust voltage and amps independently with a variable internal resistance). So your instrument cluster is still showing 15-16v. Your start stop still doesn't work and the new battery will take a battering.

Now let's code the new battery in, all values are set to 100%, the alternator load is now minimal, the instrument cluster shows 12.8v with the engine running and start stop is happy again.

A massive difference. Plus the new battery gets a full life expectancy.

Imagine the battery manager as a librarian, it monitors every amp that's checked out and tries to ensure it's booked back in.

It does this even when the car is switch off and monitors the battery sensor to see if you're trickle charging and measures amp throughput, then adds this to the battery profile/condition. A new battery will want for very little so the charge strategy is totally different.

The actual values in the Gateway can show how many amps were used whilst the car was locked, what caused the car to wake up if anything, how much charge the battery had during its recent drive cycles, what causes the start stop to disable, etc.

If even logs how many drives you do between 0-3 miles, 3-6 miles, 6-9 miles, 10+ miles to build a charge profile. It also logs the time the engine is run for throughout its life in 0-3 mins, 3-6 mins, etc.

It's very very clever and hence the reason an OPC is far from ripping a customer off when they state you need your battery coded.

My OPC fitted the CTEK Confort Connect eyelets directly to the battery posts, was this incorrect?

Also with an uncoded (no serial number on the battery so nothing to enter/code via PIWIS) Banner AGM battery fitted my stop/start works normally?

[TrackNutz]

SkinnyPete said:

Brilliant post thank you.

So what are the consequences of me not using the trickle charger correctly? I did use the snowflake mode because its cold outside but I didn't use the correct negative terminal, my CTEK wires aren't actually long enough to reach both terminals so I will need to look at this.

Lastly why is a battery now so complicated? Is it purely for fuel saving, e.g. the more the gateway knows about the battery then the less dependency on the alternator and therefore the lower the fuel consumption?

Thank you.

The consequences are that you are physically improving battery condition but the manager has no clue, so will not adjust this in the battery profile. You could trickle charge it for weeks but the state of charge would remain at say 78%. So the manager loses information and therefore can decrease battery life.

Yes, essentially it's for efficiency, fuel economy, euro emissions standards, performance (less torque loss when full open throttle - manager can cut alternator load if required) etc etc.

[SkinnyPete]

Hopefully 10 hours of my CTEK 3.8 will not have taken it too far out of its parameters...we'll have to see.

[TrackNutz]

gtsralph said:

My OPC fitted the CTEK Confort Connect eyelets directly to the battery posts, was this incorrect?

Also with an uncoded (no serial number on the battery so nothing to enter/code via PIWIS) Banner AGM battery fitted my stop/start works normally?

Do you have a photo? Both the connections and the top of the battery.

If you have a 981 or newer, then yes it is incorrect to attach the leads directly at the posts and therefore bypass the battery sensor.

[gtsralph]

TrackNutz said:

Do you have a photo? Both the connections and the top of the battery.

If you have a 981 or newer, then yes it is incorrect to attach the leads directly at the posts and therefore bypass the battery sensor.

No photo and car is on its winter holidays in storage. The eyelets are attached to the small bolts that are part of the fittings on the battery posts.

[TrackNutz]

gtsralph said:

No photo and car is on its winter holidays in storage. The eyelets are attached to the small bolts that are part of the fittings on the battery posts.

Then it's wrong. Just grabbed this screenshot from eBay.

At the bottom of the wiper assembly you should see the black rubber grommet. Through the centre goes the charging post which doubles as a securing screw. You can also just make out the small negative battery terminal sticker, to signify correct charging location.

[SkinnyPete]

Just some follow up on this, I used my CTEK to charge the battery to full (using the correct negative terminal this time!). It only took a few hours and I disconnected it for the night.

In the morning I used a cheap voltage meter that plugs into the cigarette lighter, it registered about 12.3V plus or minus .1 every other second. I then turned the ignition on and got a similar reading.

The car has been fine since but the voltage reading on the dash was 15v and stop start did not work so much, that said it's never really worked in my car (60 seconds at most) unless I turn the heater panel and PCM off then it lasts for 3-4 minutes.

Anyway, am I right in saying with the engine off the battery should hold 12.5V?

Edited by SkinnyPete on Wednesday 27th December 20:12

[gtsralph]

TrackNutz said:

Then it's wrong. Just grabbed this screenshot from eBay.

At the bottom of the wiper assembly you should see the black rubber grommet. Through the centre goes the charging post which doubles as a securing screw. You can also just make out the small negative battery terminal sticker, to signify correct charging location.

I have done some research since last posting and the 981 Boxster SIT document states:

“Every external charging/jump starting operation on the battery must be performed at the jump start terminal (positive battery terminal) and the corresponding ground terminal (on the wiper linkage). The negative battery terminal must not be used for external charging/jump starting since the battery sensor can be destroyed by voltage peaks during the charging operation/jump starting.”

This supports your advice, however, I checked with two Porsche Centres this morning and their written advice was:

".... for conditioning the battery the charger needs to be connected directly to the battery posts (via the eyelets). And the Earth is used if jump starting is needed."

I had storage company take pictures of my installation and the rather large wiper mechanism earth which are shown below:



the wiper mechanism earth:



Clearly the CTEK/Porsche eyelets cannot be attached to the wiper mechanism earth so for what it is worth that supports Porsche’s advice that a CTEK/Porsche conditioner is safe using the battery posts but for charging (implying a non-conditioning battery charger) or jump starting the wiper earth must be used because these processes will have voltage spikes (and CTEK/Porsche conditioner does not).