GoFastr

Just recently when I first start up my 2009 SL65 I am noticing that after I back it out of the garage, I have to drive it 5 minutes or so before I can operate the tilt/telescopic steering wheel or even put the top down.

I'm pretty sure it used to work immediately before but just curious if this is a battery thing like it has to get some charge in it first before these items will operate?

I only drive my car maybe once a week so maybe the battery in the rear is low?

Quadrobenz

GoFastr

When I went out for lunch today I could put the top down immediately after starting it.
Looks like this anomaly happens the very first time it starts for the day as the top opened after I got to work this morning too, but it wouldn't open in my driveway after 1st starting it.
I noticed it displayed something in the dash pod like Not Operational, Check your Owners Manual when I pulled up the button to open the top this morning.

This happened last Sunday too, first thing in the morning but on the way home from tennis the top worked fine again.
I could use the electric tilt/telescopic steering wheel at lunch right after starting it too.
Strange?

GoFastr

Thanks, that is what I am thinking. I just bought the car last year and had the starting battery in the front replaced last October and they said the consumer battery had been replaced a few months before in June and was still ok. I guess sitting around on the lot until I bought it in August and then at a shop waiting on other parts until December when it finally reached me has taken a toll on it.

I just bought a battery tender and need to investigate the best place to connect it in.

Quadrobenz

Ok, with the additional information about the recent battery replacements I believe the issue is the car is not running and driven long enough to fully charge the batteries. A battery tender might work. Its purpose is to keep a fully charged battery charged, not to charge a discharged battery.
I bought a good battery charger (Schumacher) that I used to fully charge the batteries. Over time they got worse so I had them replaced. Yours should be fine when they are fully recharged.

GoFastr

Thanks!

Note to self....drive the damn car some more and enjoy it!

Quadrobenz

Sounds like the ideal preventative maintenance plan!

GoFastr

So after reading through a few of the threads regarding ctek battery tenders I'm still confused.

If I connect it to the consumer battery in the trunk will it also charge the starting battery in the front or do I need 2 ctek tenders?

Quadrobenz

The CTek should be connected across the trunk battery. When the car is off any remaining power consumers are connected to that battery. The front battery is isolated from any loads when the car is off, it is also a different technology. It will only discharge when a cell fails and the battery needs replaced. The circuitry and controls in the R230 SL are fairly elaborate to allow one alternator to charge both batteries but keep them separate otherwise. The reason for two batteries is the brake hydraulics are electrically actuated. No batteries, no brakes! Trust me, I know from first hand experience.
A good feature of this system is the car will always start. If the trunk battery is completely dead the metal key opens the door. Then put the regular key in the ignition and the car will start off the front battery. It might take a few seconds for the starter to respond.
If the trunk battery discharges below about 60% the CTek will not recharge it, the protection circuitry in the CTek will show an error signal. That is why I bought the Schumacher charger. My old battery would discharge down to 20%, the charger would restore it to 70% in 10 minutes so the car would work normally. I also used it to start some friends cars with dead batteries. After I replaced both batteries I have no needs for either device. If the SL sits for 3 weeks it will start fine but it takes about an hour of run time to fully recharge the trunk battery.

Viper98912

I have my Ctek hooked up to the trunk battery. A slowly dying battery will tell you the signs you're seeing - can't open the top, can't use the seat heaters, etc

GoFastr

Ok thanks.

I bought a Ctek charger-maintainer so let's see how that works once I get it all hooked up.

Bdubblu

For short term storage you only need a tender on the consumer (trunk) battery.

However for long term storage, you need one on the starter battery (under hood) as well. Mines mostly stored all winter so my starter gets a tender too.