Hi, Yes, no problem. It may charge at 14 volts, but the currant/amps will change depending on state of battery & that is not constant..
Hoggy.

 

Good move going with an AGM. They pump out more current per size than any of the lead acid types. Lasts longer as well. I run them in all my cars.

 

Thanks guys,

I have been doing a little research regarding my other car, This other car has stop/start which I wanted rid of, unlike the later TT`s it can`t be switched off by coding, to get rid of this evil device I have disconnected the negative rail sensor on the battery, my car has an intelligent alternator which adjusts votage via this sensor and the ECU for energy recovery via overrun, it can also leave the battery at only 80% charged as it needs the other 20% to push 15 volts or more into the battery in the recovery phase (if there happens to be one). When the sensor is disconnected the ECU causes the alternator to default to a steady 14.2 volts level of charge. There is a lot of misinformation from manufactures stating that this steady level of charge at 14 volts or more will considerably shorten the life of the AGM battery. I needed confirmation that this is not the case.

I prefer not to have an 80% charged battery especially in the winter months, I also don`t like Stop/start, by disconnecting the sensor I have removed both problems and my battery should last much longer, It may cost me a small increase in mpg but I am happy to accept that, an added bonus is that stop/start cars have ungraded parts to cope with regen and stop/start I can now actually benefit from those upgrades.

Johnson Controls, the world's largest start-stop battery manufacturer, told BESB on August 10 that 'parties' were discussing the complete removal of the option to override the start-stop function in new cars.

http://www.batteriesinternational.com/2 ... -function/

 

Interesting concept and to be honest I've not encountered this before. The AGM batteries are basically a lead acid type that likes to have high discharge and re-charge current. I'm not really sure how it would cope with a long term regulated supply supply. It almost sounds like you want a get a gel type stand-by battery as these are designed for constant charge.

 

Hi, Constant volts is not constant charge, the amps/current is not constant & will vary depending on state of battery.
The volts have to be fairly constant & higher than the battery otherwise it can't flow into the battery.
Hoggy.

 

Hi, Constant volts is not constant charge, the amps/current is not constant & will vary depending on state of battery.
The volts have to be fairly constant & higher than the battery otherwise it can't flow into the battery.
Hoggy.

It's the rate to which this happens that determines the battery life. Voltage and current will vary with charge/discharge but if held constant over long periods (ie driving on highway) the battery life may suffer.

 

Hi, As I said it will vary & in-coming will always be greater than out-going or battery will go flat.
Hoggy.

 

Benckj,

Do all your cars have stop/start, have you an AGM battery installed in a car with standard fixed rate charging.

Rob.

 

Hoggy,

A standard alternator giving out a fixed charge of 14.1/.2 volts, is this classed as a float charge if it is I have read that a high float charge that kills these batteries, does anyone on here run their MK1 with an AGM battery.
Rob.

 

Hoggy,

A standard alternator giving out a fixed charge of 14.1/.2 volts, is this classed as a float charge as it is I have read a high float charge that kills these batteries, does anyone on here run their MK1 with an AGM battery.
Rob.

V6 & QS gave AGM spec'd as std because the battery is inside the car.

 

David C

V6 & QS gave AGM spec'd as std because the battery is inside the car.

Do those cars alternators give a constant 14.1/2 volts same as 180 & 225, I assume they are mk1`s, I see you have a 3.2 2003.

Rob.

 

If it's any help according to the climate control readout my QS will charge at 14.3v for a few minute and then drop back to around 13.5v

 

imartyn

If it's any help according to the climate control readout my QS will charge at 14.3v for a few minute and then drop back to around 13.5v

It appears it has a smart alternator then, I was hoping it had a standard output one, my 180 charges at 14.1/2 continuously.

Not all chargers feature float charge and very few road vehicles have this provision. If your charger stays on topping charge and does not drop below 2.30V/cell, remove the charge after 48 hours of charging. Recharge every 6 months while in storage; AGM every 6-12 months.

We don`t drive continuously for 48 hours therefore it appears 14.2 volts is ok, yes/no.

https://batteryuniversity.com/index.php ... id_battery
https://batteryuniversity.com/learn/art ... ss_mat_agm

 

Hi, Voltage will vary slightly depending on amount of charge/current required, on any alternator.
Hoggy.

 

Just lookong at getting a new 096 agm bosch s5 battery for the 3.2, euros do one with the discount code for £108 which I am happy with as they are only round the corner from me.

When testing current battery reads 11.1v on code 20 on recirc. with the engine off, what is everyone else getting? Engine off, ignition on and select code 20.

 

Just lookong at getting a new 096 agm bosch s5 battery for the 3.2, euros do one with the discount code for £108 which I am happy with as they are only round the corner from me.

How are you getting £108 ??
The Bosch "S5 A08" 096AGM is £181 with the blackfriday discount. :?

 

I use agm, have done for over 4 years now, always worth it if you can afford the extra cash.

 

This alternator is for sale on Ebay, it is compatible with both the 180T and the 3.2 from years 1998 to 2004

AUDI TT 8N Alternator 1.8 3.2 98 to 05 Bosch 028903030 038903024G 028903028E

https://www.ebay.co.uk/itm/AUDI-TT-8N-A ... 2348154763

How can what appears to be a standard fixed output alternator give a continuous 14.2 volts in my 1.8T and yet give out between 14.2 and 13.5 volts in Imartyns 3.2.

I am trying to ascertain what the charging regime is for the 3.2 with an AGM battery, is it static around 14.2 volts or floating to 13.5, anybody.

 

infidel.uk

I use agm, have done for over 4 years now, always worth it if you can afford the extra cash.

Thanks infidel,

I presume your car charges at steady 14.2/3 volts when being driven, this post might appear to be meaningless, I have my TT mk1 and a Merc, I have fixed the Mercs charging rate at 14.2 volts with an AGM battery connected, I don`t want to fry it with a to high charge rate, if others have used AGM at a steady 14+ volts with no problems then I will leave the hack in place.

Thanks.

 

Just lookong at getting a new 096 agm bosch s5 battery for the 3.2, euros do one with the discount code for £108 which I am happy with as they are only round the corner from me.

How are you getting £108 ??
The Bosch "S5 A08" 096AGM is £181 with the blackfriday discount. :?

Thats the starting price, you then put the code in atbthe checkout. Comes in at 108.

 

This alternator is for sale on Ebay, it is compatible with both the 180T and the 3.2 from years 1998 to 2004

AUDI TT 8N Alternator 1.8 3.2 98 to 05 Bosch 028903030 038903024G 028903028E

https://www.ebay.co.uk/itm/AUDI-TT-8N-A ... 2348154763

How can what appears to be a standard fixed output alternator give a continuous 14.2 volts in my 1.8T and yet give out between 14.2 and 13.5 volts in Imartyns 3.2.

I am trying to ascertain what the charging regime is for the 3.2 with an AGM battery, is it static around 14.2 volts or floating to 13.5, anybody.

I have been watching.my 3.2 is floats from 14.2 down as low as 13.3. I am trying the battery on mine first, as its only showing.11.1v.

Handy to onow the alternator is the same though, thanks

 

Just lookong at getting a new 096 agm bosch s5 battery for the 3.2, euros do one with the discount code for £108 which I am happy with as they are only round the corner from me.

How are you getting £108 ??
The Bosch "S5 A08" 096AGM is £181 with the blackfriday discount. :?

Thats the starting price, you then put the code in atbthe checkout. Comes in at 108.

The starting price is £329.99 ...!!
Then after the black Friday discount comes to £181

Are you sure you're looking at the 096 AGM?

 

I have been watching.my 3.2 is floats from 14.2 down as low as 13.3. I am trying the battery on mine first, as its only showing.11.1v.

Handy to know the alternator is the same though, thanks

Are you checking voltage with a meter pushed into the cig lighter socket, see link below, as it appears 11.1 volts may indicate little or no charge going into the battery and 13.3 volts when car is running indicates only a trickle charge coming from the alternator which probably won`t keep the battery charged in normal running.

https://www.ebay.co.uk/itm/UK-Digital-L ... 0033.m2042

 

The natural question to ask is, how do I know whether my vehicle has a Variable Voltage Alternator?

Variable Voltage Alternators require some sort of battery sensing technology to determine load coming from the
battery and this is done by a battery sensor which is found on one of the battery terminals (usually the battery
negative). Please see pictures below for examples.

https://www.redarc.com.au/how-do-i-know ... alternator

Does the 3.2 have that sensor on the negative battery terminal, if not how does the voltage vary between 14.2 and 13.5?.

 

David c, I will check what euros is giving me in the morning when I pick it up, if it ends up being £181 then I suppose I havnt any choice. Thanks for pointing us in the right direction.