Weak start...urgent please :D

[BFEINZIMER]

So I went and washed the car yesterday, had to move it into the street to dry it (shade in strett) so I put on the flashers and parking lights for no more than an hour. Went to start it and it wouldent turn, barly heard the starter. Called AAA cuz It was easier than getting my dads car int othe street for a jump and it took 2 tries until it started. Drove the car a half mile and left it on for 10 mins wiht lights and AC on per some instructions i read somewhere. Also I usualy keep 2 bluetooth gps's powered into the car and the hella tpms daws a small current along with my bluetooth headset charger. Been doing this for a LONG time and no issues (tpms install was recent-2weeks or so) So this morning the car turned over weak. Ok so I went and unplugged all the gps's and the bluetooth. Left the car today for around 11 hours. Came back and weak started again. So I'm going out tonight and I have jumper cables but I wanna know whats up. The OBC gives me 13.~~ reading while the car is on so I think the alternator is ok?? When I get to my friends house I'll use her dads multimeter to test the voltage by putting the + on the jumper terminal and the - on the gound and report the #...Any ideas? THANKS!

[bubba966]

The problem is your battery isn't fully charged. Don't run it with the lights on if you don't have to. Nor anything else electrical. The less power you use while it's running the more power than can be used to charge the battery.

But if it was run 'till it was dead then you're going to need a good, serious charge to get it back to being ok.

Also, check the fluid levels and top up with distilled water if need be. Water should be added when the battery is cold (hasn't been getting charged). So your best bet is to pull the battery, check/add water, and leave it on a good trickle charger for a few days. That should get it fully charged again.

10 minutes of the car idling with the AC & lights on isn't going to charge it much. Idling with the AC on helps as the AC makes the car idle a little faster. But having the lights on while you were doing it was drawing almost as much current as the alternator was putting out, therefore not really charging the battery at all.

If you don't have a charger to leave the battery on for a few days keep taking it out for hour plus long drives at 2,500 RPM or so and don't run the lights or AC, or much anything else if you can. Running the AC helps only at idle, not while driving.

[BFEINZIMER]

Ok cool well all flid levels are a-ok....um where do you mean add water....to the battery??? lol never heard of that before! i dont have a trickle sooo i dont have any planned drives either and at gas being 4 dollars a gallon im like ugh! um yea i drove it 20 mins this morning and 20 mins home today so iono...ima do these tests tho...thanks!!

http://www.bimmerboard.com/forums/posts/56742/

[bubba966]

Yes, if when you check the water levels in the battery and one or more of the levels is low you need to add distilled water to the battery.

20 minute drives is going to take a long, long, long time to get the battery charged again. These batteries are huge, and they don't get fully charged easily.

Might want to go spend even the $20-$30 and get yourself a battery charger so that you can get it fully charged before it's too late and won't hold a charge anymore.

[BFEINZIMER]

hmm i have a maintence free battery, where is there a port for water? can i do this without removing the battery? of course id need to fully disconnect it to do this procedure anyway...

[Paul in NZ]

some so called maintenance free batteries still have ittle covers on the top so you can add water(distilled is best...how old is your battery?They usually give very little warning they are about to wave the white flag....You may notice the cranking is a bit slower than usual but the first sign is usually what you have had.....if you want t give your battery its best chance of survival you must charge it fully now.....and make sure the water(sulphuric acid actually)
is over the plates.I disconnect my battery when i charge it but i am not 100 percent sure this is necessaryafter all when the car is charging it is getting a positive voltage.Also make sure your battery terminals are clean and tight

[BFEINZIMER]

yea my freinds dad is a mechanical whiz and busted out his pro multimeter tonight. getting a strong 14 from the alternator at the battery and every time i needed to start it, it had to be jumped. looks like a new battery! :/ any reccomendations?

[525i winter driver]

yea my freinds dad is a mechanical whiz and busted out his pro multimeter tonight. getting a strong 14 from the alternator at the battery and every time i needed to start it, it had to be jumped. looks like a new battery! :/ any reccomendations?
replaced mine with a 'moll' battery last fall and it has so much juice it's ridiculous - doubt you'll see -30'c over there but the moll didn't flinch - don't forget to grease the terminals with dialectric goop.
i'm surprised your friend didn't do a voltage test on the battery to make extra sure tho, but they should test it wherever you take it for the replacement if you ask.