Start stop battery

[Wolfiedingle]

Hi All

My start stop doesn’t work. I have ready in grey on the dash but it still doesn’t work.
I understand this can be a battery problem but which one should I change? Either the big one in the boot or the small one in the engine compartment. I have tested both with a volt meter and both were above 12v

Many thanks

[nu11eaf]

Originally Posted by Wolfiedingle

Hi All

My start stop doesn’t work. I have ready in grey on the dash but it still doesn’t work.
I understand this can be a battery problem but which one should I change? Either the big one in the boot or the small one in the engine compartment. I have tested both with a volt meter and both were above 12v

Many thanks

Use the charging terminals under the bonnet and both batteries will be charged at the same time.
PS; Always a good idea to state what car, model and year you have.
Screenshot_2021-02-09-11-19-14.jpg

[OldEngineer]

12v is nearly flat
12.7v is fully charged

[Wolfiedingle]

Oops sorry I have a 2018 XC60 D5 AWD
I have charged both batteries using the correct terminals and charger.
I will check again as to what the voltage was and see if they are close to 12.7v then I assume I change the one with the lowest volt reading.
Many thanks

[WhatNext?]

looks like your car has had Volvo sotfware updates too

ready was has been replaced with and A with a circular arrow

[Wolfiedingle]

I have the 12 inch display and I understand the A and arrow are in the 8 inch display unless this has changed?

[OldEngineer]

From the manual...

Conditions for the Start/Stop
function
For the Start/Stop function to work requires
that a number of conditions are met.
If any condition is not met, this will be indicated in the driver display.
The engine does not auto-stop
The engine does not auto-stop in the following
cases:
• The car has not reached approx. 10 km/h
(6 mph) after starting.
• After a number of repeated auto stops,
speed must again exceed approx. 10 km/h
(6 mph) before the next auto stop.
• The driver has not fastened the seatbelt.
• The engine is not at normal operating temperature.
• The ambient temperature is below
approx. -5 °C (23 °F) or above
approx. 30 °C (86 °F).
• The windscreen's electric heating is activated.
• The environment in the passenger compartment deviates from the set values.
• The car is in reverse.
• The driver is making large steering wheel
movements.
• The road is very steep.
• The bonnet is opened.
• When driving at high altitudes when the
engine has not reached operating temperature.
• The ABS system has been activated.
• In the event of heavy braking (even without the ABS system having been activated).
• Many starts during a short period of time
have activated the starter motor's thermal
protection.
• The exhaust system's particulate filter is
full.
• A trailer is connected to the car's electrical
system.
The following applies to automatic gearbox:
• The gearbox is not at normal operating
temperature.
• The gear selector is in M (±) position.
• If traffic conditions allow it (for example in
a traffic jam)

[Wolfiedingle]

I understand that it could be a number of things that cause it not to work but the battery is the main culprit.
One battery measures 12.8v the other 12.2v so looks like I need a new main battery

[Mad Malc]

You could try dissconnecting the small battery at the negative terminal for five minutes and reconnecting.
Sometimes the voltage sensing unit gets confused so the old computer trick of switching off and on may work. It won't cost anything so perhaps worth a try as it used to work on our S60 D3.

[Wolfiedingle]

Originally Posted by Mad Malc

You could try dissconnecting the small battery at the negative terminal for five minutes and reconnecting.
Sometimes the voltage sensing unit gets confused so the old computer trick of switching off and on may work. It won't cost anything so perhaps worth a try as it used to work on our S60 D3.

I’m not sure how this will help but I’ll give it a try