Checklist for battery change

[fabes]

Thought I would start a new thread for anyone's future reference

So planning to buy an AGM replacement main starter battery

BTW is this still the original near 8 year old battery?


Checklist before I start

1. Comand code. Do I need it or will it still work. Where might it be?
2. Windows and sunroof. Do I need to RTFM or is there nothing needed here.
3. Keys will still just work (if doing this on non MBs is anything to go by

Anything else?

Going to a fun little job as, man, it's snug in there.

Advice appreciated....

 

[AMGeed]

1 No code required for Comand.
2 Possibly need to reset both windows and sunroof. Easy to do, Ign on, open each window fully on the switch, then close and hold switch on for 5 seconds. Same for sunroof.
3. Yes, keys are not affected.

Only one thing to remember, negative terminal off first, and reconnected last. You are right, there isn't much room and its a heavy battery.

 

[fabes]

Cheers Roger
Of course, the aux battery will hold COMAND.....

I learnt very early, very quickly and very sparkly the order many years ago as a teenager.....

Yup, might even break out my Jemmy bar to help me lever the thing out. Knuckles will, no doubt, be scraped though.

 

[John]

I think the date is stamped on one of the terminals (week/year) so don't think you can tell from your picture.

 

[wongl]

Cheers Roger
Of course, the aux battery will hold COMAND.....

I am not entirely sure the Aux battery will maintained power while the main battery is disconnected. In my car, a R172, there is a Aux Battery relay that isolate the Aux Battery from the main battery. I discovered this because when I put the main battery on charge with a CTEK charger, it doesn't charge the Aux battery. Instead I had to install a second set of quick connect charger leads to the Aux Battery and charge that separately. I ended buying a second CTEK charger so that I can charge both batteries at once since finding a parking space with access to a working mains socket is extremely rare in HK.

 

[Petrol Pete]

Another Thread that would fit nicely and be easy to find in the 'Batteries and EV battery section'...that we do not have yet.

 

[Petrol Pete]

Thought I would start a new thread for anyone's future reference

So planning to buy an AGM replacement main starter battery

BTW is this still the original near 8 year old battery?
View attachment 92923

Checklist before I start

1. Comand code. Do I need it or will it still work. Where might it be?
2. Windows and sunroof. Do I need to RTFM or is there nothing needed here.
3. Keys will still just work (if doing this on non MBs is anything to go by

Anything else?

Going to a fun little job as, man, it's snug in there.

Advice appreciated....

The build month is usually stamped on one post and the build year on the other. IE: 04 then 11 would mean April 2011 etc.

 

[55AMGCLK]

Another battery related question, do you think the battery terminals still need a little grease? I suppose this was more important in batteries that were not fully sealed.

 

[flying haggis]

i have just replaced the exact same battery in my CLS with this

F21 Varta Start-Stop Plus AGM Car Battery 12V 80Ah (580901080)

i cant praise Tayna highly enough ordered 1630 mon and delivered 1250 tue fitted in less than five minutes. you need thin hands or blu tac inside the 13mm socket to extract the bolt and to get it to line up again to refit

if there was no grease on the original battery (mine didnt have any) I would keep the new battery terminals free from grease so that the clamps get a good grip

 

[Petrol Pete]

Another battery related question, do you think the battery terminals still need a little grease? I suppose this was more important in batteries that were not fully sealed.

Not grease. There are specific products on the market to use on battery terminals to prevent corrosion.

 

[ChrisHampshire]

I use one of these when disconnecting the battery (connected to a motorcycle battery) to preserve all settings/memories etc: https://www.amazon.co.uk/dp/B07WFK3Y88/?tag=amazon0e9db-21

Works a treat....

 

[pmcgsmurf]

I've never really fully understood this need to connect something to keep settings.

I always just simply remove the old battery, fit new and if anything needs reset (windows etc.) do these after.

Could see the point if you were to lose all your Comand settings and contacts etc. but for the odd thing that needs reset I think it may be more risky connecting something else up!

 

[Chrishazle]

Based on what happened to my S204 when Halfords connected a slave small battery to the OBD port while changing the main battery, I would strongly advise against this method. Although the car started, I could not move the gear stick from P. Eventually they pulled the stick surround and used the emergency release so I could drive home and get it to my local indie. He found that the OBD port was dead so his diagnostics would not work, had to go "old school" with wiring diagrams to find the blown fuse (?#18) and then fix something on the gear selection module. All told took over 2 hours (as well as a couple of days hassle for me!!) and cost Halfords £174 - which they swiftly re-imbursed, so at least that part was OK!

If you must connect a slave battery, there's an emergency +ve under a red plastic cap under the bonnet, use the top of the suspension mount for the -ve, but remember your main battery leads remain live!!!

 

[mikrt]

The build month is usually stamped on one post and the build year on the other. IE: 04 then 11 would mean April 2011 etc.

I think it's week number.....year number

4th week 2011

 

[wongl]

If you must connect a slave battery, there's an emergency +ve under a red plastic cap under the bonnet, use the top of the suspension mount for the -ve, but remember your main battery leads remain live!!!

Good advice - that was how the gentlemen from an old school battery shop in HK replaced the main battery on my car - he used a motorcycle battery with crocodile clips to the jump-start terminals before disconnecting the main battery. Then he inserted the positive terminal into a rubber washing-up glove before he proceeded to remove the battery.

Looked like he kept the motorcycle battery and the washing-up glove for this purpose only.

 

[Chrishazle]

Credit for me knowing this must go to Television, a sadly deceased but much respected member on here then on MBOA. It's now known around the Halfords network too, as the CS guy that phoned and arranged the refund said it would go out to all managers to remind them of correct procedure they should follow!!