Whoever Told me that there is nothing that can go wrong with a car that money can't fix, has never owned a Crossfire!
I have a brand new Optima battery in my Roadster. It reads 12.5 Volts, I have done a parasitic check on battery and have no drain on the battery.
However, when I let the car sit for three or four days the car will not start. Just clicks. When I charge the battery, even though it reads fully charged the car starts.
Any ideas what could be happening. Could there be a bad connection on the battery cables?
Ideas welcome.

MCPO

 

Two things:

1) have no drain on the battery.
Then you did not measure it correctly, you have drain on the battery, the question is, how much? Anything up to 55mA is fine, if you have ZERO, your meter is not connected properly, your meter fuse is blown, you have the leads configured improperly or your meter is bad.

2) Terminal voltage does not tell the entire story. When you place a load on the battery, it's internal resistance comes into play. If your test of the battery is to simply measure the unloaded terminal voltage, you have not actually tested the battery.

Exactly what is the standby current (what you call "parasitic", but there is no such thing as a "parasitic drain")? Storage batteries DO NOT like to be drained slowly over time, they are designed to deliver 200 to as much as 400 amps for a SHORT period ot time. If you have current flowing, it will raise the internal resistance of the battery, such that the load you place on it when the starter solenoid/relay closes, terminal voltage drops, many times, to where the relay drops out. Once it drops out, terminal voltage rises, pulling the relay in, so you get the click-click-click action from the relay.

Of course, you can have a totally good battery but resistance in the positive or ground leads, which gives you the same symptoms. So, have someone turn the key to start and see what your terminal voltage is during that. If terminal voltage stays at 12 or above, you have resistance in the cables somewhere (corrosion, etc.) If terminal voltage falls or jumps around, then the battery is weak, again, probably due to excessive standby drain.

 

Ok, done editing my post. Sorry, Im multitasking and I can't really do that..............

 

I have had that situation, and it was because the terminal clamp was on a corroded terminal. The car would start and then not start because of the corrosion. SoI think you have a bad connection somewhere or corrosion inside the cable sheath hidden from view.
The corrosion was common in the old days when the battery cases were made of pitch and a gap opened up around the terminal post allowing gases to escape around the terminals and cause the corrosion. Todays batteries are made from polypropylene and shrink around the terminals.

 

Thanks again Pizzaguy.
I have ordered new battery cables as the old ones are quite corroded. I think you nailed the problem......

MCPO

 

So how did the next cables do? Was that the problem?

 

Where would I buy new cables for my crossfire?

 

I would guess you have fixed this by now but it sounds like one or both of the battery post are corroded .
Retired MCPO

 

I did a google and ended up on FCP's site: $20 for a battery ground cable:
https://www.fcpeuro.com/products/mer...hoC3HoQAvD_BwE


The positive cable I have not been able to source.



The battery ground cable is available thru Mercedes, just tell them "2003 SLK320".
I would think the positive/starter cable is also available, but I KNOW the ground one is.

They are pricey, but they fit exactly and are WELDED at both ends, this is very important. "

FCP Euro

 

pizza guy,
Still having problems with battery drain. When Diagnosis shows a code P2300 which states "Ignition coil 1 circuit low."
Could this have an affect on battery drain?

 

No. Fuse 11 powers the coils, it is on "run-start" power, not battery power. When you turn the key off, the "run-start" feed at pin 1 of the switch is depowered, which is what feeds fuse 11.

 

Thanks again pizzaguy!!

 

pizza guy,
Just ran tests on my battery with following results:
After charging battery read 12.72V
Turned on lights for 2 minutes
Turned of lights and battery read 12.25
Started car and battery read 14.26v
Tested amps and find a reading of .105a
I pulled all fuses and still get a reading of .105a draw
You mentioned the alarm located on fire wall.
I will try to disconnect it.
Battery cables look good, no corrosion
Had new alternator installed last year.
Any further suggestions!!
Thanks,

MCPO

 

There are a few things that are, in a way, 'unfused'. Or they are fused thru the stud-fuses in the little box next to the battery.

If you yank ALL fuses, it's gotta be one of the loads in the little box, the alternator, or maybe the pulse module.

If you have not seen it, my procedure is attached. I'm way too busy to spend too much time here right now, got a month-end deadline I am going to miss no matter what.