I would not automatically blame the battery. What kind of voltage are you getting AT the starter, and WHAT is the voltage at the battery, IE the voltage drop under load?
How large is the cable going up front, and what did you use for grounding?
You can buy some awesome batteries in group 24 nowadays
What is the cranking amps rating on the battery you have now, and how old is it? You had it tested with a REAL tester, IE a "carbon pile"?
Have you checked? -------
Disable the ignition, get a friend, and a long length of say, no14 wire
Hook One probe of your digi meter, on a low volts/ autorange scale to the engine block
Hook the other probe to a body ground and crank. Read the voltage, it should be VERY low, the lower the better. More than .2 (two tenths) is starting to get to be too much, indicates a poor ground to the body
Now hook one probe to the engine block, the other probe to your long length of no14, and stab the other end to the battery negative POST. Crank the car, and once again, the lower the reading the better.
Now hook one clip/ probe to the starter main post, run your long wire back and stab directly to the battery POSitive post, and crank. Once again, low reading, the lower the better is what you are looking for.
If possible, borrow/ buy/ steal a "carbon pile" tester to determine starter amperage draw. The way this is normally done is to crank the engine a few seconds, and read the battery voltage at the end. Next, hook up the carbon pile unit and twist the knob until you drag the voltage down TO that same voltage reading, then QUICKLY read the draw amperage on the carbon pile tester's meter. This will give you some idea of whether the starter is "overamp."
Of course you'll have to find out what that IS. I don't have any figures on the new "mini" starters. If you have a "good" auto electrical shop/ rebuilder in your area, they should have that info.
