Crackle from the Battery

[John77]

I have problems with my wife's 2006 SLK 200 having a flat battery after a few days. Totally flat. Will not even open the doors. Anyway short story, done drain checks on fuses, but on fully charging the battery each time I have connected the battery and heard a noise that I thought was just the CD Player resetting, but today I realized that it is actually coming from the battery itself. This is a new battery to the original spec, but not MB. Exide. The old battery used to do this on recharge and connect before we replaced it. Starts off loud enough to hear then gets quieter quiet after about 10 seconds. This is why I thought that it was the CD changer which is in the glove compartment behind the battery. Any ideas?

 

[Doug1234]

This sounds like quite a large short somewhere, possibly starter /alternator wiring related.
Get that side of the wiring investigated before going further .... there is a possibility the battery could overheat / explode /catch fire...

 

[John77]

This sounds like quite a large short somewhere, possibly starter /alternator wiring related.
Get that side of the wiring investigated before going further .... there is a possibility the battery could overheat / explode /catch fire...

Thank you. I was told by an auto electrician that if you connect the battery for a couple of hours you can feel the alternator to see if it gets warm, showing a fault, but this was before I noticed the crackle. The Alternator is cold. Is the starter motor accessible form the top?

 

[alexanderfoti]

You need to measure the current to/from the battery when connecting it up, but be careful as it may be in the 50's of amps if its something big.

It could be anything, but needs a big ammeter in the ground to monitor.

How did you measure the drain when you did the fuse checks?

 

[John77]

You need to measure the current to/from the battery when connecting it up, but be careful as it may be in the 50's of amps if its something big.

It could be anything, but needs a big ammeter in the ground to monitor.

How did you measure the drain when you did the fuse checks?

Hi thank you for the reply. I did it with a digital meter across the fuses, after letting the car sit for 30 mins. The ones showing drain were Radio/Nav, Window rear soft top,Instrument cluster, ABS/ESP (Was the highest) Low beam and Diagnostic socket. I still have to test the rear fuse box in the boot.

>>>>The thing is that when you reconnect the battery with the Meter in line, the battery starts to crackle again. I also tried it with the old battery in case it was a battery fault, but it does the same.

 

[John77]

Ok so today I fitted a twist connector to the battery, so that I can quickly turn it on and off. see photo. I disconnected the alternator, connected battery no change. Pulled every fuse and relay from the front fuse box, maybe wasting my time but seems a good idea, Still a crackle, but I did notice a click on connecting the battery from the master brake cylinder of that area. So this afternoon I will go on to the in-car fuses and see what happens.

 

[Tony Dyson]

I'm puzzled at the 'crackling' sound? the noise I would describe from a wet cell battery under heavy load or charge cycle would be a distinct 'Fizzing' sound and a less intense 'Fizzing' sound from an AGM battery, I would associate a 'Crackling' sound to a high resistance joint/connection breaking down and starting to arc and spark creating carbon deposits and burning the joint/connection and insulation away from the fault, this could also explain why fuses aren't being blown yet as the fault current hasn't yet managed to exceed the breaking capacity of the protective device. The statements in your Post 05 are also confusing ?

1. Is your battery a Wet-Cell (Flooded) or AGM​
2. Describe the settings on your MM when you probed for a drain at the fuses and what readings did you get?​
3. Describe the settings on your MM when you ‘reconnected the battery with the meter in-line’ and what was your meter in-line with?​
4. A picture of your meter would help if you could?​

ETA, typo

 

[John77]

I'm puzzled at the 'crackling' sound? the noise I would describe from a wet cell battery under heavy load or charge cycle would be a distinct 'Fizzing' sound and a less intense 'Fizzing' sound from an AGM battery, I would associate a 'Crackling' sound to a high resistance joint/connection breaking down and starting to arc and spark creating carbon deposits and burning the joint/connection and insulation away from the fault, this could also explain why fuses aren't being blown yet as the fault current hasn't yet managed to exceed the breaking capacity of the protective device. The statements in your Post 05 are also confusing ?

1. Is your battery a Wet-Cell (Flooded) or AGM​
2. Describe the settings on your MM when you probed for a drain at the fuses and what readings did you get?​
3. Describe the settings on your MM when you ‘reconnected the battery with the meter in-line’ and what it was your meter in-line with?​
4. A picture of your meter would help if you could?​

Hi and thank you for the reply. The battery is an Exide premium lead acid. The new one that does the same is also an Exide MB Equivalent. It is a definite crackle, very similar to when you first connect the battery and it sparks, but this goes on after the clamp is correctly tightened and comes from the battery it's self. I have gone to the other in-car fuse boxes and removed all the fuses, but it still crackles. Now removed the carpets in the boot and got to the rear fuse box. Took all the relays out, still crackles on re-connection. took out al the fuses and it now stops on reconnection. Put each fuse back one at a time and all is well until I put in fuse number 8 and on replacing that it, it crackles again> Remove the fuse it stops, so this seems to be the problem. Fuse 8 is for the Antenna Booster. So this must be the problem.