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Discussion Starter · #1 ·
today my car just died no turn over when trying to start the engine..i needed to jump start the car,after 1 click it fired up..i took the battery to get it tested and it showed that was okay..but the guy told me that the battery i had has only 560 CCA! ..so i just started to look and found that the OEM CCA is 900CCA!..what problems can i have with running such a small battery!? the battery i have is a ACDELCO ..
 

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"what problems can i have with running such a small battery!?"

I think you have just had them. Once the engine is running, your small battery is fine. The trick is getting it started under all conditions.

Lead acid batteries are rated for Amp-Hours (capacity) and their ability to supply high current for short durations at low temperatures, which is the CCA, or Cold Crank Amperes. CCA is physically determined by the internal impedance of the battery coupled with the capacity.

The bottom line is that the battery you have is too small for an E39 M5. The starting loads on a higher compression engine require a bit more oomph than your battery can deliver. You need the correct Group 94 size battery.

Does the AC Delco battery rattle around in the battery bay when you go around corners?:biggrinbounce:
 

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Discussion Starter · #3 ·
The battery doesnt rattle at all..but once i got the beast sideways and the car just died!..i thought damn just broke the car.got to the trunk and the small battery got disconnected.hooked the cables up and she startd right away..

the problem is that my local and only bmw official dealer in my country sells the battery for 400 bux and they dont carry it on stock..so i need a good replacement..what should i be looking on the new battery? CCA numbers??
 

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Either buy a group 94, or another, slightly smaller option is a Group 49, which is what BMW uses in most of their vehicles. The group 49 will work fine as long as you don't have to do lots of below freezing starts. Your locale shows Dominican Republic, so I think your safe! You don't need to worry about capacity, or CCA, just buy the correct group size. I run a Group 49 here in Southern California. I added a little foam on one side, to take up the slack space, and the cables still fit. Saves a little weight and works fine. If i had to crank it on a Minnesota morning, I would definitely want the Group 94.
 

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Your battery is too small - 560 CCA isn't enough to start the car regularly regardless of temperature.

There are several other factors and ratings as well such as "reserve", Cranking Amps (maximum when it is warm), and physical size you should consider.

Simply put, you need a new battery. What to look for? I'd worry primarily about physical size (can't use it if it is too big!) and CCA. Get yourself a good 850+ CCA battery that fits in the opening and everything else will take care of itself.

If the dealer battery is too expensive you might want to check out Optima Battery. When I thought I killed my battery earlier this year, I settled on a RedTop 34R as a replacement - no first hand experience since my battery didn't actually need to be replaced. Note that you need the R (not a regular 34) because our + and - posts are swapped from a normal vehicle.

d-
 

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Doug,

Did you fabricate any special hardware to mount the Optima 34R? I put one of those in my 911 back in 1995, and it's been going strong ever since! Nice and light.
 

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My battery didn't end up being dead so I didn't replace it.

My plan, however, was (and is when my battery eventually dies) to cut a styrofoam holder for it out of a large block.

d-
 
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