Battery woes

[DITTRICH]

Dear All

My C230k's battery has run down as it has been parked up SORN at the parent's house. They are supposed to run the engine for 30mins every week, but what ho! - its flat, even with a solar trickle charger.

What I think I need to do is...

1 open the C230k boot manually and disconnect the negative.

2 hook up the jumper cables from my W124 E300D engine compartment to the c230k battery - do the positive lead then the negative. **Note to find where in W124 engine compartment there is positive and negative feeds**. There ought to be ample juice in this W124 **big** battery and the jumper cables are bigger **diesel** ones.

3 start the E300D engine and run the engine for 15 mins to put some charge back into the C230k battery.

4 disconnect the jumper cables. Reconnect the c230k negative cable to the battery. hopefully start the C230k from its own battery.

I have been told that the C230k has an electronic instrument cluster and to avoid any unfortunate events, I should disconnect the negative lead.

Is my cunning plan sound or is there a tiny flaw in it?

Les

 

[imadoofus]

**Note to find where in W124 engine compartment there is positive and negative feeds

On the battery. Big plastic box thing at the back on the nearside

PJ

 

[DITTRICH]

Ha Ha Ha!
I thought the battery was under one of the back seats.
I confess never having actually gone to search for it yet.
Rgds
Les

 

[IanA2]

Call the AA?

 

[BTB 500]

Just as an aside, the battery will quite likely be b*g*ered. They start to suffer damage to the plates below 12.4V (which equates to about 75% charge). You should always keep lead/acid batteries fully charged, if possible. Not actually sure that 30 mins running at idle would put back what starting the engine took out?!

 

[GrahamC230K]

Just as an aside, the battery will quite likely be b*g*ered. They start to suffer damage to the plates below 12.4V (which equates to about 75% charge). You should always keep lead/acid batteries fully charged, if possible. Not actually sure that 30 mins running at idle would put back what starting the engine took out?!

My vote is no. Actually, I would say that activity accelerated the drain of the battery! Doh.

Finders crossed your boot lock is not corroded like 99% of MB's with automatic boot releases. I fear your key will not work - it sounds like you haven't tried yet. I think someone lese got into this situation - I forget the fix - smashing the rear tail lense I believe.

Let us know and we can commence the search for the thread!

 

[DITTRICH]

Before I left the car there I did WD40 the boot lock and check that it worked. It was (at that time) very very stiff but eventually opened. So hopefully it will be okay.
Its a bit of a bugger really as a space in my apartment car park retails at £15k and I only have 1 space. They were only £5k when I bought my apartment 6 years ago! I should have bought 10 of them.
Thanks for the advice. My fingers are crossed.
Rgds
Les

 

[philharve]

... 3 start the E300D engine and run the engine for 15 mins to put some charge back into the C230k battery.

Hi DITTRICH

If the battery is TOTALLY flat you will be lucky to start the car with just a quick 15min. charge from a second vehicle. If it does start then the battery could let you down again when you least expect it. I would put the battery on an overnight charge with a battery charger and measure the SG of each cell the next day. The battery could be damaged (dead cell?) which might explain why it went flat.

Healthy batteries do hold their charge for a very long time so your car must have been laid up for many months? You don't say what type of battery it is: liquid or gel?

I discovered some months ago that if the battery doesn't attain a voltage of at least 11V, the car won't start, or rather it will refuse to start. You'll hear a 'click' when turning the ignition key but there will be no attempt to activate the starter motor, even with an apparently good battery. This is a MB design feature that ensures that sufficient charge is available for life support systems, lighting, heating, etc.

I would give the battery a nice long charge and have it professionally checked. This service should be free.

Measuring its voltage with a multimeter isn't sufficient. At one time they used to check batteries by placing a resistive load across it and measuring the current and voltage drawn. However, attaching the load caused sparking which could ignite the explosive vapour given off by the battery. These days they use a device resembling a multimeter which gives the status of the battery and an indication of any faults with it.

REGARDS Phil