Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Long term battery disconnection

On a 2009 era car, what are the likely implications of leaving the battery disconnected for 3 or 4 weeks assuming it is fully charged when it is put back?

ECU re-learning, radio re-coding etc. Can it cause any major or long term harm?

Presumably any re-flashing of the ECU does not get lost as I guess it would be in some form of ROM non volatile memory.

Same question if it's only a day or two?

Not sure I will need to do it but just checking in case.

I can't see an issue other than those you raise but the ECu of that age I'm guessing will be fine. I would & do use a battery conditioner but maybe you don't have access to power.

We disconnected a newish 2004 Mitsubishi Shogun Pinin battery many years ago when laying up as leaving the country. 18 months later after a couple of hours on a charger, re-connected and it started instantly and ran perfectly. Almost certainly any adaptive mapping will be lost but ECU will re-learn.

Personally, I use a Victron charger.It has several interesting functions such as:

- smart charging

- deep discharged battery recovery

- remote checking of the battery status thanks to the Victronconnect application

I use it on all my cars, I highly recommend it.

https://www.victronenergy.fr/chargers/blue-smart-ip65-charger

Quick report back on this.

Had the battery out of the car for about a week.

Put it back in this morning and the car fired up first time and ran just as it did before. No issues, no warning lights and the radio still works so no loss of codes etc.

Needn't have worried.