battery lost charge..proper way to charging it - BMW Forum

wcre34 · 09-07-2005, 08:37 AM

My car battery ran lost charge, im changing the alternator soon but i have no power and dont have another car to help me jump start. I do have a battery charger my question is can i just pull the battery out and charge it outside the car or should i just leave the battery and charge it.. if i leave it in the car should i charge using the jumpstart instruction where u hook it under your hood/bonnet or directly to the battery in the trunk/boot ??thnk

nukeduster · 09-07-2005, 10:00 AM

Leave it in the car, connect it under the hood to the correct jump start hookups. Keep in mind most batteries aren't meant to be deep cycled(used until dead).. batteries never hold a full charge after that.. so if your alt is bad, and you don't want to keep ruining batteries, change it ASAP.

wcre34 · 09-07-2005, 11:56 AM

change the batt too u mean? i was thinking about going optima battery i guess this is my chance

rej487 · 09-07-2005, 12:37 PM

Quote:

Originally Posted by wcre34

change the batt too u mean? i was thinking about going optima battery i guess this is my chance

THat's exactally what he means. Because once that battery dies it will no longer hold 100% charge EVER AGAIN!!! Best you'll prob. get is about 65 - 75% charge out of ur battery...

wcre34 · 09-07-2005, 12:46 PM

i reckon so oh well gonna go get optima battery tomrrw if i could then as far as fixing my alternator goes need to figure out what the number of voltage regulator it is.. so i could replace it..

97alpineM3 · 09-07-2005, 02:07 PM

Optima batteries are great... I've driven for more than 30 mins with no alternator with one of those...

Les

Cruzin 323is · 09-07-2005, 07:47 PM

i would def recomend changing the altenator first... then buy the new battery or do it the same time.. and start fresh!

e36_m3_Turbo · 09-07-2005, 09:05 PM

Keep in mind, alternators dont charge a battery, they only keep a fully charged battery full.

wcre34 · 09-07-2005, 09:21 PM

yea but if the voltage regulator went bad the alternator wont charge the battery or charge it too much but in this case it havnt show sign of dimming lights and all.. but the battery charge lights came on.. so before i jump to a heavy thing i want to do battery first to see..but the BMW shop i took my car to get radiator and maintainance done said it was the regulator problem without a diagnostic either he was going by experience i cant really tell since this is my first bmw..