Voltage check

[sean sherry]

We live and we learn..... Still chasing Battery reliability. on W204 c class
Checking the Voltage via the onboard system on the Dash is not accurate due to voltage losses in the wiring System. For accuracy use a Voltmeter on the battery Posts.
New Varta battery went flat overnight !!!! Battery tests ok. Oe rear door was ajar slightly and the system may have registered a Drain. ????
Tomorrow morning will tell.

 

[sean sherry]

Tomorrow has come and all is well. The C Class electric Systems had a good night's Sleep shutting down all the currant Draws.

My research tells me that an Alternator can charge 100% but can run the Battery down over night due to leaking Diodes. ( one way switches )

 

[Patrick_R]

Sean
I don’t understand what has happened here?

Was your battery flat again?

 

[sean sherry]

Sorry Patrick...please remember I'm Irish....
Battery was ok , i assume that it was an excess current draw when a rear door was not tightly closed. ie slightly ajar and preventing the various on board computer controls from shutting drown. I'm not sure how this all works as it takes about half an hour to shut all the electronics to shut down. Could be that there are various large Capacitors slowly draining and keeping some systems alaive.???