Economy Mode (Battery)

[Cresco750]

When I bought my X7 in December I noticed that the battery saving economy mode would activate within two or three minutes after the ignition was switched off. Having read how sensitive these vehicles are to battery voltage I decided to replace the (possibly original?) battery with a new high quality Varta brand battery. Now, the electrics go into economy mode as soon as the engine is switched off.

I guess there is the extremely unlikely possibility that the new battery is a dud, but there are no other indications or issues suggesting that this is giving problems? Any other possible causes? I have Lexia but nothing has shown up on that.

 

Thanks.

[paul.h]

Welcome to the forum.

 

Check the voltage on the new battery in case it is faulty which is not unknown. Should be about 12.7 volts before the engine is started. You could also put the old battery back to see if it goes back to the previous 2 or 3 minutes to discount anything else.

[Cresco750]

Thanks for that. Unfortunately my el-cheap-oh multimeter doesn't read down to the decimal place, so it only showed 12v (although I would have thought it may have rounded up to 13v if the actual voltage was I deed 12.7v? Dunno.

 

Anyway, when i changed the battery over I thought I would be clever and keep the circuit powered with a small battery and jumper lead while the main battery was being changed, rather than totally disconnect and do a reset of the BSI. I just did an BSI reset now and it seems to have improved things; the first time the ignition was turned off it took 13 minutes until economy mode activated. However it seems that all subsequent times are back down around the three or four minute mark. It's not the end of the world, and three minutes is plenty long enough to be useful, but it would be interesting to know why it's nowhere near the "up to one hour" that is mentioned in the Handbook?

Edited March 22, 2016 by Cresco750

[Johndouglas]

The time before economy mode kicks in is dependant on the level of charge in the battery. It might be worth you buying a decent voltmeter then you could also check the output of the alternator when the engine is running. It should give you a reading of around 14.2

[Cresco750]

Will do. Out of interest, what sort of times do most other X7 owners see?

[Johndouglas]

what sort of times do most other X7 owners see?

I started my C5 this morning which was the first time since Saturday and it hadn't gone into economy mode, although it no doubt would have done within three or four minutes had I not started. But other things need to be considered. My C5 doesn't have hydraulic suspension so no suspension pump to hit the battery before even switching on. Also my battery is 74amp/hr - others maybe 72 or even 70. Also it is comparatively new.

[paul.h]

You do not need to pay much  for a decent meter, less than £10 will get you one that can be used for most things around the house and car such as this from Toolstation and other places sell very similar ones http://www.toolstation.com/shop/Electrical/d190/Electrical+Test+Equipment/sd3348/Digital+Multi+Meter/p11867

[MikeLane]

 "and three minutes is plenty long enough to be useful"

Not sure what you mean by this. My (Mk2) C5's radio turns off after about 10 mins if the engine isn't running. It will do the same if I simply start the engine and then switch off (however I need to have the ignition on).

[Cresco750]

"and three minutes is plenty long enough to be useful"

Not sure what you mean by this.

I mean it's long enough to put windows up, listen to radio while I put my tie on / finish my coffee etc before exiting the vehicle 😉.

 

You say that you can get the radio to come back on after it shuts down after ten minutes by leaving the key on; this would suggest that it is still in economy mode, wouldn't it?

Edited March 26, 2016 by Cresco750

[Parkesie]

Economy comes on dependent on battery voltage but also has a time related to how long the engine has run since the last time it was in economy mode.

[4rchibald]

Economy mode is an algorithm that calculates battery drainage and it takes information from the small module installed on one of battery's terminal. It can't be switched off on X7s, but DiagBox allow to change battery capacity stored in the ECU. Unfortunately capacity stored goes up to 74 AmpH, whereas mine is bigger and Economy Mode appears quite often.

Parkesie is right, the longer you drive the lesser chances are to see Economy Mode.

Apparently ECU update helps with this issue, but I have not tried it yet.