Start Stop Battery Question

[TC350]

First up, I like the Eco stop-start. It's never proved to be a problem for me, always restarting instantly and when required. Whether or not this is down to the magnificently smooth 3.5 litre V6 petrol engine in my car, I don't know.

Back to the OP's question. There may not be a problem with your aux battery. There are plenty other things to check first.

The system requires a whole raft of conditions to be met before it will work. Your manual will tell you what they are but they include:

• Engine up to temperature
• Interior up (or down) to set temperature
• External temperature not too low (as it has been for the last few days)
• Windscreen not misted
• Driver's seatbelt fastened
• BOTH batteries sufficiently charged

I've had my car from new 13 years ago and never touched the auxiliary battery in the boot. Two years ago the stop-start became reluctant to operate even though everything, including the batteries, seemed to be OK. With the main battery being over ten years old, I decided to treat the car to a new one. That's all that was needed to get the start-stop working again as it should. It also gave me the peace of mind that I was less likely to be let down by a failing battery.

 

[Gazwould]

The original main batteries are real work horses this was February 2021 and it's still starting .






Interesting to see how long it goes .

 

[MrGreedy]

So I have noticed the Eco light in my newly acquired 2013 E250 CDI Amg Sport Coupe is orange. And stop start doesn't seem to work.

Is this a private sale newly acquired, or purchased from a car trader/dealer?
If bought from a car trader/dealer and the battery isn't working properly, this is a pre-existing fault and the trade seller must rectify the problem. You wouldn't need to put your hand in you pocket in this case.

 

[Jay1960]

I think the car has been stood around a while. So going to put the main battery on charge.

Ironically the ECO light went green today and stop start started working so looks like probably just needed a charge so going to charge that after the main battery just so I know I have done it