Originally Posted by
Padgett
Maybe you had better explain what is happening. If the battery is not able to start the car after 5-6 days then either the battery is not holding a charge or something is draining the battery.
Try charging the battery fully, disconnect the negative lead and check the voltage after an hour. Let sit for 3-4 days (sounds like you can) and check the voltage again. It should not be significantly different.
This much is easy, from here it requires a bit more expertise.
Next put a load on it (100A is good) and see how much the voltage drops. This will tell you if the battery is bad or not.
Finally connect the battery and let sit with everything off for about a 1/2 hour. Connect a DVM in series on a 10A scale and lift the battery terminal. The DVM should now read the quiescent drain & should be less than 50 ma (I usually see about 20). 200ma will drain a battery in 3-4 days.
If there is a drain, I usually start pulling fuses until it goes away. If not then disconnect the alternator. Eventually the culprit circuit will surface.
All of this talk of CCA and Reserve and I/20 is just clouding the issue, there are larger factors at work here. Optima (and AGM in general, lately I have been getting Duracells but they went from $99 to $137 in a year) are very good batteries but can fail.
I have no tools to measure,
the strange thing is that I repeat to charge battery charger with over 13 volt car starts badly