[bluejmc2005]

Hi all,

Thanks in advance for your help with this. My car is a 2005 E90 330d auto saloon. PLEASE SO NOT CRITICISE ME FOR BEING AN IDIOT - I KNOW I AM - IF ANYONE HAS SOME GENUINE ADVICE TO HELP i'D BE VERY GRATEFUL. I am in Gloucester, U.K.
The trouble started when the battery - original - died at the start of the cold weather, approx 4 weeks ago.

We changed the battery - same size etc and recommenced spec for this BMW.
Then the issues started.

after about a week, the car was acting very strangely (random resets of clock etc)
We looked at the battery compartment and it was NOT fully secured, meaning there was movement in the battery. On top of the battery where the rectangle block thing is was VERY hot, and we could see that the connecting between that and the smaller rectangle box had seized together. A friend came over, and said that he felt the problem was that because the battery was not secure, it kept sparking there and that had caused it to seize. We disconnected the battery, and went about trying to separate the two. We succeeded, but it meant the screw that connects to the smaller part had gone and they could not longer be easily connected. he said to me we could fashion our own connection using some bolts etc, anf then when the battery was secured, it would be fine. So we did that and made sure all was secure this time, no issues. Started fine. reset the airbag light that had come on as part of the battery gremlins using the PC, and all was well. We have driven the car over 450 miles over Christmas, returning late 27th.

This morning, I go to the car and start it - very cold - car really struggles to start but does. I let it warm up, deice etc, and then go on my way to asda. suddenly, hear a pop sound from the back, airbag light comes on, abs light comes on. I immediately turn the car around to go home, red battery light flashes up, then the service light.

I get her home, switch her off and find the smaller black box has come off of the main connector that we fashioned. The connector is RED hot. The smaller black box has evidence of melting. I disconnect the negative, and post here. here are some pics.

I know i should have gone stright to a garage and got this sorted properly but money, time etc and I trusted my friend. Clearly, his method has not worked. Does anybody have any suggestions or ideas? ANY help appreciated. The car drives perfectly, runs perfectly, and had zero issues prior to the original battery dying. Its serviced regularly (last oen in November)

https://i.imgsafe.org/4fe907492b.jpg
https://i.imgsafe.org/4fe9171bb2.jpg
https://i.imgsafe.org/4fe9237dcc.jpg
https://i.imgsafe.org/4fe93142cc.jpg

[Thermobaric]

Was the new battery coded?

[Digitalize]

Take it to a specialist, preferably by trailer, I wouldn't reconnect the battery or try and start the car, let them reconnect a power source and plug it in to diagnostics, see if all the modules are okay and then go from there.

[bluejmc2005]

Thanks both for taking the time to reply. Prior to seeing your replies,I have been out again - the little plastic box that "melted" comes off easily and leaves a metal lead. i can see that it melted because the makeshift washer I used got hot. If I plug that into where the plastic box was, and make sure there is a connection to the power distribution box, the car starts etc. I think my issues are 2 fold. Firstly, what is causing that particular connection to get so hot (alternator sending too much current perhaps?) and then i need a quick, safe and reliable way to clamp those two damaged bits together, rather than a washer and bolt!

or - as you say - give up and take it to a garage!

[08njSTEP]

Think of electricity like water through a hose. When you kink the hose it balloons out. That is your washer thingy. The resistance is too high and the electricity has to go somewhere. The worst that can happen is a fire. There is a possibility of damaging other electronic devices. If you can't fix it correctly take it someplace that can. You are just asking for a catastrophic event at this point.

[bluejmc2005]

Originally Posted by 08njSTEP

Think of electricity like water through a hose. When you kink the hose it balloons out. That is your washer thingy. The resistance is too high and the electricity has to go somewhere. The worst that can happen is a fire. There is a possibility of damaging other electronic devices. If you can't fix it correctly take it someplace that can. You are just asking for a catastrophic event at this point.

Indeed - thanks for replying I appreciate it. A low resistance connection is required, question is whether this is something i can do myself, or whether a garage is the only option

[Digitalize]

Take the battery out, remove anything you've done and start fresh.

The battery should just drop it, be secured by a clamp at the bottom and then the connectors should be secure on the terminals, no need for anything to change.

Then you need to code the battery to the car, if you haven't done this it could be the cause of your issues.

You need to be careful because whilst the car has fuses, the modules are fairly delicate and won't like being connected and disconnected quickly, it could cause the memory within them to become corrupt, then you'll have to start looking in to if you can reflash them or have to replace modules.

[Sensible_]

Have you replaced your old battery with an AGM one of is it a like for like bog standard battery?

If it were me, I would do the following:

1. Check red BST cable resistance at battery and fuse box ends. Check for corrosion and burning of the cable.

2. Replace above cable if needed.

3. Replace entire battery connector with official part.

4. Replace battery with BMW recommended like for like or upgrade to AGM.

5. Code battery if not like for like.

6. Register battery.

[bluejmc2005]

Hi all,

If I was to buy a whole new battery positive lead with BST and distribution box, is it easy enough for me to detach the old one? That way Ill have whole new connections and a replacement used part is approx 80.

like this:-
free adult image hosting

[bluejmc2005]

Originally Posted by Sensible_

Have you replaced your old battery with an AGM one of is it a like for like bog standard battery?

If it were me, I would do the following:

1. Check red BST cable resistance at battery and fuse box ends. Check for corrosion and burning of the cable.

2. Replace above cable if needed.

3. Replace entire battery connector with official part.

4. Replace battery with BMW recommended like for like or upgrade to AGM.

5. Code battery if not like for like.

6. Register battery.

like for like battery. Is it possible to remove the positive lead from the boot of the car or is it one complete lead that goes to the front of the car? I have seen the part posted in last post, but wonder if its possible to simply swap them out

[ed330D]

Have a look on realoem. often a good starting place when trying to figure out what part you need.

http://www.realoem.com/bmw/enUS/show...diagId=61_1946

If you are going to use a washer, brass would be preferable to steel. Search google for brass penny washer; it will find other brass washers besides penny washers.

[Sensible_]

I'm not 100% on the differences between the black and red distribution boxes to be honest.

The bit that you will need to double check is the BST. The explosive part which runs from battery to alternator / starter.

It's probably better to replace like for like. What's your current part number?

Also be wary of buying 2nd hand. If it's been involved in a collision and the BST has been activated then you have problems...

[Sensible_]

Here are 3 pages from the e90 voltage document. It shows your black distribution box.

Hope it's of some use.

[bluejmc2005]

Originally Posted by Sensible_

Here are 3 pages from the e90 voltage document. It shows your black distribution box.

Hope it's of some use.

Thank you this is amazing!

[bluejmc2005]

Originally Posted by Sensible_

I'm not 100% on the differences between the black and red distribution boxes to be honest.

The bit that you will need to double check is the BST. The explosive part which runs from battery to alternator / starter.

It's probably better to replace like for like. What's your current part number?

Also be wary of buying 2nd hand. If it's been involved in a collision and the BST has been activated then you have problems...

Yes fair point. Hmmmm.