Steve, I believe I will have to differ with you on your last post. If you have an exceptionally large battery connected to a system that has a very small charging capacity, the charging system will never satisfy the battery and it will charge continuously trying to get the battery up to a charged state that it can hold the system designed voltage. The charging "dynamo" in this case our generators will try to maintain the system designed voltage (approx 12v+) no matter how many things are turned on. If a battery is in the system and it is not charged to the system designed voltage or to the voltage that the battery is designed to hold, then that battery appears to the "system" as a load and the generator will try to supply it. Once a battery has reached its system designed voltage, then the voltage regulator would lower the output requirement of the generator. But if the battery never can come up to its voltage, then the regulator will keep the generator charging. And this could be to the generators demise. As an example of a generators ability to self destruct, many years ago when I bought my Healey, one of the things I rebuilt quickly was the generator. To my surprise when I took it apart was that the solder in the commutator leads had become so hot that is melted and the solder was slung out by centrifical force in that it was splayed all around the inner casing of the generator. Surprising, the generator was still working. But after I repaired and installed it, checking the setting on the regulator, it appeared that the regulator never allowed the generator to not charge. I believe the overcharging was distroying the generator. So I suppose that an alternator will just charge the exiting battery faster to its designed voltage. And I suppose that 525 cca is sufficient for the electrical load that I will be putting into the Healey. But if you consider extra electrcal load than original, such as, fog lights, a very good stereo, auxiliay power for ipad and cell phones, etc. Now that I have a 65amp alternator, might I want a larger battery? Dave.