We had not used the car for two weeks and when I attempted to yesterday, it would not start. I figured I must have a power drain somewhere because the battery should be good. Nevertheless the key opened the driver door only, not all four as usual. The instrument lights came on when I turned the key, the starter clicked, but no go.
I had it jumped and it fired instantly. Drove it around for a bit and parked for the night.
- First oversight on my part was not to disconnect the battery, so In the morning I was faced with same issue - Instrument lights come on- turning the key gets a few clicks but no go. Now I knew for sure there is a power drain somewhere.
I went for the jumper cables again thinking I really need to get it charged this time.
Just before getting in the car to give it a go, I noticed the the positive end of the jumper cable was not seated properly on the Battery terminal - Without thinking I reached for it, disconnected and repositioned getting a huge spark in the process. (what was I thinking being so reckless !!)

What have I done ? -
No instrument lights come on when I turn the key, and no clicking sound at all.Real dead. The battery now reads less than 6volts across terminals.The OVP fuse seems good - Still I replaced it with a backup with no effect.
Where do I need to look (for a blown fuse ?) TIA

126 - 300SE 1987 Euro

i think you just have a dead battery

__________________
1989 300ce 129k
( facelifted front,updated tail lights, lowered suspension,bilstein sports, lorinser front spoiler, MOMO steering wheel, remus exhaust,stainless steel brake lines). (Gone)

1997 s320 154k (what a ride). Sold with 179k miles. Replaced with Hyundai Equus

1994 e320 Cabriolet 108k



1972 280se 4.5 153k Owned for 12 yrs, sorry I sold it


[/SIGPIC]

Have a look at the battery leads to make sure the contact is good and then that the neg lead is well grounded to the frame. Mine did this and it was the neg lead that wasn't grounding properly.

Either that or the battery is done.

6v at the battery means it is completely dead, not just drained. 6v means half the cells are no longer functioning.

Battery completely drained = ~11v Anything less means a cell is dead.

__________________
2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k

Thought it was still good - for I have had it for just over a year.
Will replace battery tomorrow and see. thanks for now

Probably still under warranty then...

You can go to most auto stores and they will test your battery for free also.

__________________
2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k

It took me a couple of days before I got to the car - with a different battery.
To my great relief car started up immediately, so my fear of damage (from the spark) was unfounded.

All systems seem ok but I disconnected the positive lead of the battery for now, before embarking on the real project - tracing what caused this all- the power drain.

I thank you all for the advice and support.

that is wild, this happened to me TODAY. not the huge spark thing, but the dead battery. I left it to charge all night with 12volts6amps and this morning it is only reading 25%. off to the multimeter!

__________________

77' 300D, "Cartman" SOLD @ 150K (didn't know what I had)
83' 300SD, "The Superdon" 325k+ @ 28mpg
95 E320 wagon, "Millennium Falcon" 231k+ @ 24 Mpg
95 E300D, "Sherley" 308k @ 33.69 Mpg, currently anticipating a head
99 Suzuki Intruder "Trudy" @ 45 mpg

Batteries are not what they once were. Get a wal mart brand as ive seen they have the easiest replacement policy. As much as I hate to admit that. A gel battery ma be the way to go, I might try that next but I only get about 3 years to a battery.

If a battery is completely empty (11 volt or less) the internal resistance is very low. Attaching a fully loaded battery may result in a very high current, enough to kill the battery (or both). Potentially dangerous, some batteries just explode!!

The safe way is to use a good charger.
If not available a headlight lamp is series with the battery maximizes the current to +/- 5 amps. Just leave it connected until the battery has at least 12 volts. Using both high and low beam maximizes the current to +/- 10 amps, still safe.

Rob

For me the battery issue has been resolved, but could you please explain more about using a headlight lamp. I've not heard of this before

Can anyone tell me and/or send pictures on how to lower rear headrest on a e320 2004

If the resistance of the battery is close to zero, the lamp gets 12V, with a 60watt lamp, the current will be 5 amps.
When the battery has more charge the resistance will rise, the lamp will get a lower voltage, but there will still be enough current to charge the battery in a controlled way.

If you connect a fully charged battery directly to a completely drained one, the current can be very high (several hundreds amps).

Of course you can't jump start a car through a headlight lamp, just slowly charge it until it reaches a safe voltage.

It is an old trick, from before the electronically controlled chargers.

Rob