Battery Short

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DeltaD

Member
Joined
Nov 23, 2019
Messages
52
Location
France
Car
CLS 320 CDI Coupe
Hi. I dropped a box spanner across the terminals while fitting a new battery (Bang) to my 2008 CLS 320 CDI. Battery OK and the windows reset alright but there are a few lights up on the dash and the radio is now dead. Not tried starting the car as under present restrictions going for a run is not an option here in France.
Anyone experienced anything similar please. Cheers.
 
I would try disconnecting the battery for a few minutes, with a plastic spanner
 
A short circuit across the battery terminal should not cause any damage to the vehicle electrics (apart from possibly buggering up the battery by buckling the plates if left long enough.
I would disconnect the battery negative for a couple of minutes then reconnect a try and start it - preferably without the proximity of said box spanner :) .
Depending on year/model you might need to reset windows, esp (or abs, cant remember) and might just possibly need the radio code - if it does, Mercedes can supply it usually at no cost.
 
Aha, looks like I need to extend the default warning that I give, to "before touching the negative terminal ensure the red plastic cover is on the positive terminal" !! As everyone says, I doubt you have broken anything, just disconnect the negative terminal for 5 mins, but before you touch that, ensure the positive is covered with the red cover that it should have !!

Hope you sort it!

Cheers
Richard
 
If it's any help when I was only knee high I decided to test my Dad's new car battery by shorting it out with a bread knife as it sat in the hall waiting to be fitted.

After a brief lesson in arc welding and ohms law I had enough gumption to sharpen the tip of the knife which had vaporised and put it back in the drawer. The battery was fine and no one was the wiser - except me of course.
 
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While we are taking the proverbial. a battery is a current source with a very low impedance.

Spanners have a very low electrical resistance.

you now know what happens when the two are connected!!! :D:D:D
 
Many thanks
 
Has your sight returned?

I got away with it which I do realise was very lucky.

I did learn something from the experiment. I went on in later years to be an Electrical Engineer and understand that high fault currents are seriously dangerous over and above the electric shock risk. I've done some manual high voltage switching on the old oil filled 11kv switches which was an interesting experience but safe if done methodically. If you omitted to change the oil it eventually became slightly conductive and the switch could go bang. Spiking cables was fun too.
 
Reminds me of a time when moving a sailing dinghy round a car park at dusk, we didn't see the four phase power cables in the trees, big flash, most of Burseldon was in blackout mode, and my nice new Proctor mast had some holes in it. The thing was I was lending the boat to a friend who's wife was heavily pregnant at the time, I thought she was going to give birth on the spot!
 
I got away with it which I do realise was very lucky.

I did learn something from the experiment. I went on in later years to be an Electrical Engineer and understand that high fault currents are seriously dangerous over and above the electric shock risk. I've done some manual high voltage switching on the old oil filled 11kv switches which was an interesting experience but safe if done methodically. If you omitted to change the oil it eventually became slightly conductive and the switch could go bang. Spiking cables was fun too.
Snap. I switched 11kv. 33kv 66Kv up to 132Kv with the REC’s and while seconded to the CEGB 275Kv, just shows how easy it is to make fundamental mistakes. I’ve had banks of batteries on various boats and never dropped a gooley. So to drop this one with a flamin’ box spanner on my pride and joys battery was mortifying.
 

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