Looking at changing my battery and realize that i need to use a memory saver is it ok to plug into the OBD port and put 12v to it ? or would it be safer to connect to the positive & Negative cables under the bonnet ?

If anyone has done this any advise would be appreciated.  I do know a new battery has to be coded to the car and can do this with my Vaws 3.0 reader.  

Hi,

I didn’t use any memory saver when I changed the battery of my MY18 Mk3. 
All data where kept in memory though (daily trip mileage, radio stations, etc.)

when i had to remove my battery, i didn't connect any "memory saver" device to my car.

the battery was disconnected for a couple of hours whilst i did some work on the car.

 

the result was that my Trip computer mileage readings reset - but that's no biggie.

i also needed to re-learn the power windows one touch auto up/down - it is however a simple process.  plenty of youtube vids showing how to do it.

 

apart from that - everything else was fine.

You don’t need a memory saver of any kind. Not really a thing on modern cars at all.

 

Replace battery

start engine and turn wheel lock to lock slowly.

restart engine

clear fault codes

 

done 

Thanks all that's a great help, gone are the days when you could just disconnect it and replace.. now coding battery to car needs to be done. 

won't bother with the memory saver now.. Thanks all

I still tend to connect a slave battery up to any of our cars when removing the battery or replacing it, and yes I connect that in nowadays via the OBD2 port - probably even still got a "memory saver" that plugs into the mains though!

 

You can use that OBD2 port to connect a solar charger up as well, saves faffing around with leads passing over door seals.

 

But, as said, not entirely necessary, but maybe slightly convenient if you can't handle losing your "fuel computer" information!!

 

Edit:- just remember to slip something over the +ve battery lead if you do end up using a memory saver, to stop it ending up earthing on some part.

Edited 11 November, 20241 yr by rum4mo

5 minutes ago, rum4mo said:

I still tend to connect a slave battery up to any of our cars when removing the battery or replacing it, and yes I connect that in nowadays via the OBD2 port - probably even still got a "memory saver" that plugs into the mains though!

 

You can use that OBD2 port to connect a solar charger up as well, saves faffing around with leads passing over door seals.

 

But, as said, not entirely necessary, but maybe slightly convenient if you can't handle losing your "fuel computer" information!!

 

Edit:- just remember to slip something over the +ve battery lead if you do end up using a memory saver, to stop it ending up earthing on some part.

Many thanks for that very well explained.

The other day I had to replace the battery in wife's car and to avoid the hassle of recording, I decided, first time in my life, to use the "connect leads to another battery" method.

Besides a lot of extra cursing and manouvering because of the leads' clamps in the way, so moving sideways and whatnot, when I finally managed to put the thing in its place and tighten everything, I went to start the car and I noticed I must have man-handled one clamp and lost contact and the effort was useless. 🤪😁

Moreover, only the trip and clock were reset, but the radio kept all the stations! 😆

I changed my battery last year from EFB to AGM. Never even thought about memory savers. Changed it over then let the engine management know battery type had changed using OBD11. Started up and drove off with no problems.

9 hours ago, BillyParker said:

I changed my battery last year from EFB to AGM. Never even thought about memory savers. Changed it over then let the engine management know battery type had changed using OBD11. Started up and drove off with no problems.

Many thanks, it's just that I have read so much about these memory savers I did want to give myself any problems, never had to use them on my previous cars.

thanks again I won't use one and will just register the new battery once I've changed it.