Stop start stopped working

[nu11eaf]

Originally Posted by AB-UK

Just a thought but the battery on the previous model XC90 was notoriously feeble - you only had to have the radio on for an hour whilst cleaning the car for it to give you a battery low warning.

So, perhaps if you have a number of ancillary items running, such as aircon, radio, phone charger etc., one of the (very) many on-board computers has anticipated an unacceptable power drain on the battery if the stop/start system should be engaged, and is preventing it from working.

Or maybe its another thing that volvo cant get right on the XC90, no phone chargers on, radio on very low as it just adds to the atrocious suspension and road noise, and you would think it would have worked a few times in the last few weeks, 3 months old and sorry to say wish I had not bought it, over priced over hyped and over here. If the suspension/road noise was not as bad I could live with it, but it is not a pleasant car to drive or be driven in. I would not buy another XC90, sad as they are the most practical SUV, I had 3 of the original XC90's.

[gaby]

Originally Posted by AB-UK

Just a thought but the battery on the previous model XC90 was notoriously feeble - you only had to have the radio on for an hour whilst cleaning the car for it to give you a battery low warning.

When I bought my XC70 in 2003, I negotiated to have the biggest battery that would fit.
After more than 13 years, the battery is still the original one.

[Clan]

Originally Posted by gaby

Perhaps the low voltage theshold for the stop/start system is not the same as the low battery warning voltage.
Is there a low voltage warning fot the stop/start battery?

The stop/start uses the normal battery , It doesn't go by voltage but by How charged it is , below 80% charged it will not operate . The Low battery warning on the dash is voltage triggered .

[gaby]

Isn't all info concerning battery charge level deduced from voltage?
What other parameter is available to measure charge level?

[Clan]

Originally Posted by gaby

Isn't all info concerning battery charge level deduced from voltage?
What other parameter is available to measure charge level?

No , there is a lot more science to it . There is a mini computer in the negative battery terminal which measures TIME , VOLTAGE ,CURRENT FLOW , BATTERY DRAIN , BATTERY CHARGE , this is working 24 hours a day and there are calculations which go on , the data is passed to the Central Electronic Module .

[nu11eaf]

Originally Posted by nu11eaf

Or maybe its another thing that volvo cant get right on the XC90, no phone chargers on, radio on very low as it just adds to the atrocious suspension and road noise, and you would think it would have worked a few times in the last few weeks, 3 months old and sorry to say wish I had not bought it, over priced over hyped and over here. If the suspension/road noise was not as bad I could live with it, but it is not a pleasant car to drive or be driven in. I would not buy another XC90, sad as they are the most practical SUV, I had 3 of the original XC90's.

Update: car has just had the 3 month quality assuance check and stop start worked on the way home from garage, now if only they can get the satnav voice command to understand english, and fix it so you can put house numbers in when using postcode manual imput.

[mrlossyman]

Originally Posted by nu11eaf

Update: car has just had the 3 month quality assuance check and stop start worked on the way home from garage, now if only they can get the satnav voice command to understand english, and fix it so you can put house numbers in when using postcode manual imput.

14 days in and it's not come on once! Perhaps I have a problem...

[gaby]

Originally Posted by Clan

No , there is a lot more science to it . There is a mini computer in the negative battery terminal which measures TIME , VOLTAGE ,CURRENT FLOW , BATTERY DRAIN , BATTERY CHARGE , this is working 24 hours a day and there are calculations which go on , the data is passed to the Central Electronic Module .

That seems to imply that the negative terminal of the battery isn't directly connected to the chassis,
meaning that the chassis and the nagative terminal of the battery are not on the same potential.

[nu11eaf]

Originally Posted by mrlossyman

14 days in and it's not come on once! Perhaps I have a problem...

Try going on a long run, 30 mins or more and see if it works (best in eco mode) if it still does not work at least that will eliminate low battery voltage. When you first get a new car you spend a lot of time sat in car setting things up and finding out how things work without the engine running so you may just have low voltage on the start stop system. I dont know why mine stopped working but after getting it back today its fine.

[GMTRB5]

Mine started working pretty much immediately, so something not right there if it hasn't come on at all ... not that I'd miss it, first thing I do when I drive off is to turn this off as I hate the engine stopping and starting whenever I get into traffic...