Need to jump start CLK (209)

[Eddy77]

Battery is flat. Car parked in road away from house. Am I ok to jump it using one of those mini jump packs that you keep in your glove box and simply clip on the battery to start the car. Neighbour witnessed my predicament and lent me this mini jump pack. He reckons they are brilliant. I had a bit of a doubt and didn’t try it there and then.

Read the CLK manual which explains the usual jump start routine. Red on first, then black. Take off in opposite order.

So it would seem fine. But the internet abounds with stories of fried ECUs from jump starting.

What’s the deal? I do have a smart charger in the garage which I will be hooking the car up to when it is home, and I could remove the battery and charge it in the garage, but that’s a load of hassle if I can simply jump it in ten seconds.

Thoughts?

 

[slade1]

If you are worried take the battery out and charge it up. You will have to reset the windows afterwards.

 

[91dm]

I've never had an issue with jump packs or jumping from another battery. The only thing I do now is remove the key from the ignition when connecting the battery. If the battery is completely dead, no dash lights etc I would remove and charge it first.

 

[tonyspicer]

I used to have the same issue with my CLK 350 and bought a Jump Starter pack from Halfords, which worked a treat. I used to find after three weeks of leaving the car even a new battery would die.

 

[DSM10000]

The car surely has a special terminal under the bonnet for connecting the positive lead from the battery pack / jump lead?

My W203 had this, it was underneath a red plastic cap and there were some other components underneath which I assumed were to help prevent surges? I used this terminal 3 times with no ill effect to the car. The negative lead I connected to a lug on the suspension turret.

 

[MD5]

Using a booster pack you should be fine, it's car to car that can cause issues.

As DSM1000 says, look for connecting posts, and depending how flat your battery is, it may take a while for power to trickle across from the booster.

 

[Eddy77]

Yes, it has the red flap and chassis negative terminal. I use them when hooking up my smart charger so I will use the jump pack on those. I know to not hook directly to the battery due to sparks and gas etc

So it sounds ok to proceed with the little booster device. Thanks all!

 

[MancMike]

We've jump started my mrs insignia for 18 months pretty much daily, with one of those little jump starters, your neighbour is right, they are brilliant. Mine eventually failed, but it was used as I say, far far more than it was ever designed to be.

I've also jumped it several times with jump leads from my car. Never had a problem. I'm not sure I believe all this about frying ECUs, why would it fry it? It's only the same amount of voltage the car is supposed to have running through it.

 

[Eddy77]

We've jump started my mrs insignia for 18 months pretty much daily, with one of those little jump starters, your neighbour is right, they are brilliant. Mine eventually failed, but it was used as I say, far far more than it was ever designed to be.

I've also jumped it several times with jump leads from my car. Never had a problem. I'm not sure I believe all this about frying ECUs, why would it fry it? It's only the same amount of voltage the car is supposed to have running through it.

That’s good enough for me! I’ll be trying it when I get home! I think the issue with ecus is more related to incorrect procedure like crossed terminals and when using a donor car. These mini jump packs seem pretty good. Will simply follow the instructions to the letter!

 

[Eddy77]

It didn’t work. So I will be calling my local Indy to get it going! Thanks for all input!

 

[PobodY]

Oh dear! - Any chance it's that the battery is so flat that it acts as a capacitive load?

 

[DSM10000]

Oh dear! - Any chance it's that the battery is so flat that it acts as a capacitive load?

AAs above.

Remove the battery and either charge it off the vehicle or try another known working battery.

 

[Eddy77]

I suspect that is the issue. Disconnected the battery to remove it but hadn’t got a long enough socket to reach the battery securing cover bolts so couldnt get it out. Why is stuff like this so tedious. Am giving up and calling the mechanic to sort it. Windows need resetting now as the battery has been disconnected and reconnected and they are stuck ajar. Overall a load of ball ache. Rant over! Anyway thanks to all. Will post back when resolved!

 

[MancMike]

The little jump starter won’t start the car without the battery to help a little and smooth the power.

If it’s that flat, then leave the jump starter connected for a few minutes, you should see the percentage charge of the starter fall, when it’s fallen a fair bit, fully charge it again, connect and start.

 

[Eddy77]

So I was up early. Had a root around in the garage and found a long reach 13mm socket. Great! Went out to remove the battery but could I get the nuts off the cover that keeps the battery in place? Nope. Easing oil applied. Still nope.

Now I’m a pretty competent bloke.....do lots of diy.....just finished refitting my bathroom so am pretty handy with tools and stuff. So WHY is everything to do with cars so fecking hard to do? I can tackle any job successfully around the house but whenever I try the simplest task on any car, I get stuck either due to things done up too tightly or stupidly difficult access. This battery cover is a prime example. Impossible to reach easily. Obscure access. Can’t get much leverage. Why? Why make it so hard to access. Removing the battery should be so simple. It drives me mad that crap design makes things like this so hard to resolve. Next stop is to buy a T bar wrench to get some more leverage on the nuts. But honestly, what a bloody performance. As you can tell I’m well and truly hacked off!

 

[PobodY]

You think that's bad? Try installing a 3" turbo elbow without removing the turbo or exhaust manifold; not only is there limited access, but everything is welded in place from all the heat cycles.

 

[DSM10000]

So I was up early. Had a root around in the garage and found a long reach 13mm socket. Great! Went out to remove the battery but could I get the nuts off the cover that keeps the battery in place? Nope. Easing oil applied. Still nope.

Now I’m a pretty competent bloke.....do lots of diy.....just finished refitting my bathroom so am pretty handy with tools and stuff. So WHY is everything to do with cars so fecking hard to do? I can tackle any job successfully around the house but whenever I try the simplest task on any car, I get stuck either due to things done up too tightly or stupidly difficult access. This battery cover is a prime example. Impossible to reach easily. Obscure access. Can’t get much leverage. Why? Why make it so hard to access. Removing the battery should be so simple. It drives me mad that crap design makes things like this so hard to resolve. Next stop is to buy a T bar wrench to get some more leverage on the nuts. But honestly, what a bloody performance. As you can tell I’m well and truly hacked off!

It is the classic "5 minute job"

Once those words are spoken then the evil mechanical pixies are drawn from whence they lay and into our realm where they then cause havoc, thwart every move and hide the essential tool needed to complete said "5 minute job"

 

[Eddy77]

Well a combination of the heat and other things to do meant I never got any further. My trusty Indy is popping round today and take it into the workshop to sort everything for me. I think the battery is totally goosed and I’m sure a few STAR resets will be needed as the battery has been disconnected. Will post back!

 

[Eddy77]

Update, for anyone who is interested.　


Indy recovered it to the garage. Removed battery, which was the original from 2008, so 10.5 years old. Battery was totally goosed, so new one fitted, STAR diagnostics run to check everything. Various resets and sync things done and it's as good as new.　Also had a drain test done to check nothing is zapping the battery when parked up.

Big shout out to Huxleys Mercedes in Fleet, Hampshire. Been using them for years and they are so helpful and always get everything sorted with minimal delay.　

100% recommended for those of you who live in Hampshire but can't get all the way down to Ollie at PCS!　

Definitely one of the good guys when it comes to alternatives to the Main Stealers.

Thanks again to all contributors on the thread

 

[MatC63]

Glad to hear you got it sorted. I had a problem following a new battery from Halfords that wouldn't hold a charge for more than a week.
Turned out that they had sold me the wrong battery half the size of the one that should have been in there. I have to admit the full size battery is a tight squeeze in that recess and I had to modify the holding bar which retains the battery.