HELP. Battery question

[jdvorwe]

When I got home from work today, I was going to take the BMW for a spin. I went to the trunk and tried to unlock the car and it wasn't working. I thought weird and didn't really think anything of it. Then walked around to passenger door unlocked the door and reached over and unlocked the driver's side (the lock is screwy on the driver's side door). Anyway, walked back around and tried to start it and nothing happened. And then I was like, fuck now it makes sense and I have no way to lock my driver side door. Went back to the trunk and noticed this :




The leak starts right underneath the battery tray area and looks like it was washed down the parking lot.

Then, it started pouring down rain. I ran inside and waited for a break in the rain. Went out and pulled the battery and it is dry underneath in the tray. I originally thought the storm earlier in the week leaked in through the sunroof drain or something and affected it, but it just rained pretty hard and it is completely dry. Noticed the tray was like a yellowish color and there was like a pile or white dust looking stuff that didn't smell too good (kinda like a stink bomb aka sulfur). Anyway, the yellow makes me think the battery somehow is leaking since it is sulfuric acid inside the battery (and Sulfur is yellow)?

Good news is the Battery is fairly new and has a 18 month warranty so hoping to get that replaced tonight or tomorrow morning, but I feel like I need to source the problem to keep this from happening again since it is definitely a major inconvenience. Do you guys have any ideas?

I can try and take some more pictures of maybe the battery tray or something, but when I ran out since I was trying to beat the rain I didn't have my phone or camera on me.

[Sagaris]

Get your charging system checked out ASAP! As you are probably aware, you can take your car to any auto parts store and they can test the system for free. You may just have a battery that is leaking due to physical reasons ( cracked casing ) or it could be overcharging which is a very bad thing.

I had a 2002 Toyota Rav4 that became completely ruined due to overcharging.
It created an untraceable current draw and damaged some of the electronic components. The car began throwing random CEL's that had no basis, died at random, wouldn't start or even attempt to crank. I sold it for 1/3 of its book value since it doesn't make sense to buy a new ECU, gauge cluster, and other items from the dealership or whatever other parts sources exist for newer non-enthusiast cars. I noticed rust stains on the driveway too, but this was too late since I had only connected the dots while diagnosing the car.

Once you get the problem resolved (hopefully a faulty battery, otherwise a ne alternator/voltage regulator), fix the battery tray area and repair any rust.

[jdvorwe]

Looks like PO put the wrong type of battery in the car when he sold me the car. He put in a 49-50 and e30s need 48-50. I guess I should just add that to the list the PO screwed me over with. lol. Cleaned up everything and installed my new 48-50 battery, the auto parts store was real nice and swapped them for me no charge even though it wasn't a direct exchange.

Hopefully this was the only problem. I guess time will tell.

[E30_fiend]

did you get your charging system checked while you were there? A wrong sized battery has never given myself or anyone else I know, a problem. I think your alternator is over charging your battery and caused it to boil over.


Taylor

[jdvorwe]

They said it was cause it needed a breather hose and the 49-50 didn't have that. Obviously if my battery is dead I didn't take my car there. Can I just put a multimeter on the pos. and neg. leads and check?

[E30_fiend]

If you have a way of testing voltage while running AND revving then yes you can do that. You would be best off having a friend rev to about 3k and check the voltage. It should raise to ~14v and at idle it should be at around 13.5v


Taylor

[bmwguy325is]

I say run a VAT40 on it and stuff. But yes check for over voltage. One other thing is held down? As in have a battery hold down.I have exploded a few batteries from them sliding around and the plates inside killing each other.

[jdvorwe]

If you have a way of testing voltage while running AND revving then yes you can do that. You would be best off having a friend rev to about 3k and check the voltage. It should raise to ~14v and at idle it should be at around 13.5v

Alright, thanks. Will do that whenever it stops raining.

[jdvorwe]

My friend said when he had an overcharging problem on his Cherokee earlier this year he had a problem with his negative lead? Do you think it is probable that I may just need to replace my charging leads?

Tonight when we were trying to check it out I turned the car on and and he said it (edit: it being the battery) sparked when I turned it on (so I got out and went to the trunk just to check it at idle) then when I put the multimeter on it it started smoking almost immediately and I don't think I kept it on there long enough for it to get a reading/didn't notice if it had one or not (more worried about the smoking).

I had multimeter set on DCV 20. Correct me if that is wrong?

Either way I am replacing the alternator in the near future, I am doing a 327i swap so I am going to use the "i" alt. I get with the swap. But should I take it a shop/auto parts store to get battery checked/definitive diagnosis? Or can you guys tell something from what I have said. Definitely seems like it could be an overcharging issue to me.

[jlevie]

Smoke from the meter probably means it was configured for current measurement, not voltage.

[jdvorwe]

Alright. Just went and tested again.

Engine off: 12.5ish
Idle: 13.6ish
Didn't get to test it reving because I was by myself.

So with these results, that means my alternator is good?

[jlevie]

The alternator is probably good. Prove that by checking the system voltage at 2500rpm with and without a load from the high beams and HVAC blower set to max.

[jdvorwe]

I had my girlfriend press the gas, she didn't really get the concept of "rev it". haha. Anyway, before I could explain it to her it started raining and then she had to go to work.

She lightly pressed the gas and held it and the readings on the multimeter stayed the same. They were varying from 13.3-13.6. Isn't that a little low? My battery was reading a little more drained though, 12.2 (with the engine off).

[browntown]

My eta had an odd little water catch gizmo in line with the breather hose that collected red water like that. My i just has the breather hose straight out the bottom grommet. Next battery will be sealed gel I thinks.

[jlevie]

If the system voltage doesn't rise with an increase in engine speed with a fully or nearly fully charged battery, the alternator is suspect. But if the battery is only reading 12.2 volts with the engine off, the battery is only at 50% charge or is bad. Charge the battery overnight and check 30 minutes after disconnectin the charger (should be 12.7v). Then turn on the head lights on high beam to see that the voltages is at least 12.6v. If battery voltage falls below that, replace the battery. Then repeat the alternator system tests.