Stock Battery
 

I was just wondering if the stock battery on a 03 3.0 a deep cycle battery:taz:

My opin, is no it is not a "deep cycle" battery.
Deep cycle batts usually have less cold cranking amps
than a normal car batt., but several times the normal
reserve capacity of a std batt. Deep cycle batts can
also stand many near to total discharges and still come
back to near normal...reg. car batts. usually cannot.

The stock batt is a very good one, imo. Just not a
true "deep cycle", in my estimation.
BR,mD

I would also agree it is not a "deep cycle". Are you looking for a deep cycle battery? The OEM battery in BMWs is actually pretty decent. Usually lasts a long time too!

The one in my M3 was atleast 5-6 years old when I finally replaced it with an Optima Red Top. Next will be a track battery though.

alright thanks for your help guys. im adding a second battery thats why i asked and i heard it wasint good to mix deep cycle with non deep cycle batterys

No - Deep cycles are found only in Marine and Motorcycle applications.

You could easily swap our stock batteries for a Marine equivalent...

d-

Newport - May I inquire on the need for a second battery -- needwise ? If the alt is not providing enough juice for your components when they are on, then I would rethink your layout and setup.

FWIW, I fitted a Odysseey PC1700MJT into the stock location as it was almost due for a change - at the 5 year mark but at that time, I was undergoing a full false floor amp install so it was the last time I ever wanted to be down in that hatch area again.

i dont have the money for a alt yet. i was running 1000 watts on the stock bat with 4 gauge wire. i just got done with putting a redtop optima in the battery tray this morning. im going to upgrade the wires to 0gauge havint gotten a chance to put the subs back in but if i still see the prob. ill consiter getting a stronger alt. by the way do you know how much the stock alt on my car puts out?

Sounds like a powerful system, but you know that the batteries won't help for anything other than extended playing, right? If your alt can't keep up with your amp it won't matter if you have 2 batteries or 10, you'll just end up killing them...

d-

yea i know there wasint anything wrong with the car like the lights wasint dimming or anything. just the subs were craving power

I believe the alt is 140 amps. I have 3 amps in my setup - no second battery.
Trio Of Arc Audio SE amps.

Figure out your components and revaluate from there IMO.

334 per midbass
110 per tweeter and minrange
420 per sub (2 subs)

what kind of battery do you have

Battery is a Odyssey 1700MJT