Dead battery issues

[mayanktanwar]

Increased electrical loading puts more strain on alternator, so the battery gets used more to fill the gap so to speak. Also It takes far longer to fully recover a battery than people think by just driving...1 to 2hrs in reality...unless you turn everything OFF..

Why do you think that certain electric heavy items are not available on the very "ECO" cars?...

Fit a bigger case size ad or a battery that can be deep cycled more & TBH VW has skimped on the sizing & fitted the one that will "just" do

Increasing the case size is not the solution of problem. In your car standard fitment of battery is 70 Ah and you installed 90 Ah or 100 Ah, it will increase electrical load capacity but also harms electric components. For example you shoes size is 9 and you wear 10 or 11, that's why please choose standard fitment or Ohm fitment recommended by manufacturer.

 

[golfdave]

Increasing the case size is not the solution of problem. In your car standard fitment of battery is 70 Ah and you installed 90 Ah or 100 Ah, it will increase electrical load capacity but also harms electric components. For example you shoes size is 9 and you wear 10 or 11, that's why please choose standard fitment or Ohm fitment recommended by manufacturer.

I never stated that fitting a bigger battery will 100% cure the OP's problem, he needs to find the cause first!

However it is well known that VW has skimped on the Ah rating (size) of the batteries as my car has a battery of similar Ah (size) to my previous car & yet has way more electrical load & accessories!

Fitting a bigger case size (Ah) will NOT harm the cars electrics as it is still a 12V battery. If you stick to the physical case sizing that VW design the battery tray for then you are ok.

Even if you swap out your "duff" battery for the exact same size/type & have the stop/start feature you need VCDS to tell the control module that a new battery has been fitted. You can also use VCDS to tell the control module that a bigger battery & different type has been fitted also.

I have had a bigger battery & different type fitted (compared to factory) for over 20 months now & NO problems, NO fault codes etc.

Other people has successfully done it, & I have done same to all my cars over the past 22yrs all NO problems so I really do not know why you state that fitting a bigger battery "but also harms electric components.".

 

[mayanktanwar]

I never stated that fitting a bigger battery will 100% cure the OP's problem, he needs to find the cause first!

However it is well known that VW has skimped on the Ah rating (size) of the batteries as my car has a battery of similar Ah (size) to my previous car & yet has way more electrical load & accessories!

Fitting a bigger case size (Ah) will NOT harm the cars electrics as it is still a 12V battery. If you stick to the physical case sizing that VW design the battery tray for then you are ok.

Even if you swap out your "duff" battery for the exact same size/type & have the stop/start feature you need VCDS to tell the control module that a new battery has been fitted. You can also use VCDS to tell the control module that a bigger battery & different type has been fitted also.

I have had a bigger battery & different type fitted (compared to factory) for over 20 months now & NO problems, NO fault codes etc.

Other people has successfully done it, & I have done same to all my cars over the past 22yrs all NO problems so I really do not know why you state that fitting a bigger battery "but also harms electric components.".

It's good thing you have not faced problem till now.

All car batteries comes with 12V but Ah is different. If you discussed with any automotive experts, he don't allow to increase the battery case that fitted in Vehicles. Because all battery cases are fitted by manufacturers by it's standard measurement.

 

[golfdave]

It's good thing you have not faced problem till now.

All car batteries comes with 12V but Ah is different. If you discussed with any automotive experts, he don't allow to increase the battery case that fitted in Vehicles. Because all battery cases are fitted by manufacturers by it's standard measurement.

I still don't have a problem with mine!..

Also you are wrong with your statement of ""If you discussed with any automotive experts, he don't allow to increase the battery case that fitted in Vehicles. Because all battery cases are fitted by manufacturers by it's standard measurement.""

You obviously have NOT seen the engine bay of a MK7 Golf & have not read my "how to guide" on this subject that I have linked to previously!

The MK7 Golf has a battery tray which has 3 positions for the battery clamp. This is to accept 3 different sizes of battery depending on spec & your countries importers specification requirements. Therefore YOU CAN fit a bigger battery if you have the smaller 2 sizes from the factory.

I have spoken in detail to Bosch/Varta/Exide etc in the UK technical depts. Some of these companies make the factory batteries for VAG.

VAG specify standard battery case sizes (physical dimensions), BUT they specify (have made) different Ah ratings for their batteries compared to standards Ah ratings for those same case sizes by the same manufacturer which leads to (on purpose) confusion as you think that only a VAG battery will fit/work. I know this because this is what they told me!

So long as you can physically fit the battery in the tray & clamp then you can fit any Ah rating.

I really do not know why you have this strange idea that fitting the biggest case size (that the tray will take) in my car will cause damage, I have never in 22yrs of car mechanics heard of a higher Ah capacity battery damaging a car!

 

[dr_mat]

You can fit a larger batteries any day of the week with no risk to the car, other than the extra weight being an issue at the front of the car. You may choose to increase the capability of the alternator to accommodate the potentially higher charge requirements too, but you don't really need to.

 

[ColinStone]

A 12v battery will only charge above 12.5v. So if is showing 11.73v on a charger, then it ain't charging.

To find parasitic draw and if you have an ammeter, connect it between the pos lead and pos battery terminal. Take meter leads outside car to meter and lock it. Current draw should be around 35ma after everything has settled down, may be an hour or so. Any more and something is still on.

60ah battery, typical for a petrol engine, should be charged at around 6 amps initially. Charge current will drop quite quickly and once over 80% takes some time.

Measure voltage with engine running - should be around 14.2v to 14.4v.

Suspect duff battery.

 

[david.throup.54]

I'm having a similar problem and have been in the habit of leaving OBDeleven in car. Not anymore. Battery already back to 70%. Used the dongle to get this in the msd

 

[dr_mat]

It does seem to me that when there's a diagnosis cable installed the car management computer stays active. That would certainly be enough to drain the battery in a few days.

 

[Swoope]

It does seem to me that when there's a diagnosis cable installed the car management computer stays active. That would certainly be enough to drain the battery in a few days.

i leave my obd11 bluetooth dongle in all the time.. my car goes un driven 4 days a week often. never had an issue..

beers

 

[dr_mat]

Perhaps it requires an active pairing with a phone to create more drain?

 

[ktbaird]

Joining the club (few of us). I just got the OBDeleven and I paired, did one Soundactor code and left both the dongle plugged in all night AND I do leave my keys in the car. I wasn't thinking too that that had something to do with it but I find it hard to believe. Is it possible our cars have been hacked into via this dongle?? It doesn't make sense. My car happened to right on 8500 miles. Mk7 R, DSG DCC. The car was possessed... That's the best way to describe it. I couldn't even tell if the car was on or off. I'll post a video showing the tach flickering. Auto seats were weakened which told me he had to battery related. I'll was jumped by a service guy with a jumper. Hoping I don't need to buy one to continually resolve this...

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[DV52]

Joining the club (few of us). I just got the OBDeleven and I paired, did one Soundactor code and left both the dongle plugged in all night AND I do leave my keys in the car. I wasn't thinking too that that had something to do with it but I find it hard to believe. Is it possible our cars have been hacked into via this dongle?? It doesn't make sense. My car happened to right on 8500 miles. Mk7 R, DSG DCC. The car was possessed... That's the best way to describe it. I couldn't even tell if the car was on or off. I'll post a video showing the tach flickering. Auto seats were weakened which told me he had to battery related. I'll was jumped by a service guy with a jumper. Hoping I don't need to buy one to continually resolve this...

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Kt: I wouldn't be too paranoid about OBD11 hacking into your car - Yours is not the first example of increased battery drain when you leave the OBD11 dongle connected to the car - particularly if you have KESSY.

I don't know for certain, but I suspect that the dongle stops the control modules from going into sleep mode - probably because the OBD11 dongle is continuously asking the CAN Gateway to poll the other control modules in the car and because the power for the Bluetooth transmitter is coming from the car's battery. This has the effect of a sustained, increased load on the battery for an extended period. Result is that if your battery isn't in peak condition, the minimum threashold voltage for the control modules is achieved and "odd" things start to happen - like the demonic car possessed observations that you reported in your post!

Important aspect to note: If you are having the car jump-started by the "service guy" and your car has a battery monitor control module -J367 (it looks like a "bock of plastic" that is next to the negative battery clamp), then make sure that the negative lead from the other battery is connected to the car frame (i.e. it is not directly connected to the negative terminal clamp for the car battery) - see below. Mk7s with J367 fitted have a special lug near the negative battery clamp for this purpose - but any naked engine bolt will suffice. Same applies when you are using a battery charger!!

The reason for this procedure is to ensure that J367 measures the electrical current flow into the car battery from the external battery/charger. What happens if J367 is fitted is that the current measured by J367 is recorded in a table that is stored in the car's memory and this table is used by the various control modules as their view of the battery voltage (i.e. control modules don't use the actual battery voltage, they use a calculated form of this voltage). So it's very important (if J367 is fitted) that this table is accurate and practises like incorrectly connecting a jump-battery/charger destroy the veracity of the calculation!
Don

 

[ktbaird]

Kt: I wouldn't be too paranoid about OBD11 hacking into your car - Yours is not the first example of severe battery drain when you leave the OBD11 dongle connected to the car - particularly if you have KESSY. I don't know for certain, but I suspect that the dongle stops the control modules from going-to-sleep and this has the effect of a sustained, increased load on the battery for an extended period. Result is that if your battery isn't in peak condition, the minimum threashold voltage for the control modules is achieved and "odd" things happen - hence the car possessed observations!

Important aspect to note: If you are having the car jump-started by the "service guy" and your car has a battery monitor control module -J367 (it looks like a "bock of plastic" that is next to the negative battery clamp), then make sure that the negative lead from the other battery is connected to the car frame (i.e. it is not directly connected to the negative terminal clamp for the car battery) - see below. Mk7s with J367 fitted have a special lug near the negative battery clamp for this purpose - but any naked engine bolt will suffice. Same applies when you are using a battery charger!!

The reason for this procedure is to ensure that J367 measures the electrical current flow into the car battery from the external battery/charger. What happens if J367 is fitted is that the current measured by J367 is recorded in a table that is stored in the car's memory and this table is used by the various control modules as their view of the battery voltage (i.e. control modules don't use the actual battery voltage, they use a calculated form of this voltage)

Don

Thank you for this info. Copying it all as most is over my head but will learn more and take your advice.

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[ktbaird]

Some info / response directly from OBDeleven: there is one important thing if you want to leave dongle connected. You must disconnect from car before closing the app, to do that go to My car and press red disconnect button at the bottom of screen. Battery drain example: You are checking Live data and device is in the loop of reading live data parameters from car and you just go out without disconnection, then dongle doesn't get request to stop read of live data and it is reading it all over the night

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[dr_mat]

Some info / response directly from OBDeleven: there is one important thing if you want to leave dongle connected. You must disconnect from car before closing the app, to do that go to My car and press red disconnect button at the bottom of screen. Battery drain example: You are checking Live data and device is in the loop of reading live data parameters from car and you just go out without disconnection, then dongle doesn't get request to stop read of live data and it is reading it all over the night

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Bingo. Good call.