210 flat battery - I wonder why?

[welland99]

A few weeks ago I was away from home for the weekend and acidentally left the keys in the ignition overnight. When I discovered the keys, the battery was too flat to start the engine (engine would not turn).

It started easily with jumper leads from a much smaller battery, and charged itself enough to start from cold after only 3 miles of town driving. So, I conclude that it was not very flat.

The puzzle is why it was flat at all???

The key was definitely not switched to position 2, though it may have been switched to position 1. Alll lights were off (including interior lights).

If the key is in the ignition (switched to off), are any circuits drawing current?

And if switched to position 1, what is drawing current?

 

[LawrenceMB]

I'm pretty sure the EIS itself will draw a little current with the key in it, which in turn must put some of the circuits into a kind of standby mode ready for use. I know even with the older models (140's, etc) when you do a current draw test (connect an ammeter in the main battery circuit to see what might be faulty & flattening a battery) you have to take the key right out for the current draw to get down to (almost) zero.
Basically I don't think it's anything to worry about if the battery is holding a charge when you don't leave the key in the ignition

 

[Dieselman]

The CAN circuit will have stayed alive with the keys in.

 

[welland99]

I'm pretty sure the EIS itself will draw a little current with the key in it,

What is the EIS?

 

[welland99]

The CAN circuit will have stayed alive with the keys in.

What is the CAN circuit?

 

[richard]

EIS is the electronic ignition switch

CAN is the car's network between all the control units (little computers controlling different parts of the car). If it is awake, lots of the control units are awake and using power.

Cheers

Richard

 

[welland99]

EIS is the electronic ignition switch

CAN is the car's network between all the control units (little computers controlling different parts of the car). If it is awake, lots of the control units are awake and using power.

That sounds like a silly design. It should surely switch itself off before the battery becomes too flat to start the car.

Anybody know the power consumption of the CAN?

 

[Danny DeVito]

Of course position one is not there for a fun count down .....