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      05-16-2009, 10:21 AM   #57
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Drives: E30 M3; Expedition
Join Date: Apr 2007
Location: USA

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Originally Posted by HP Autowerks View Post
Your alternator will mantain a proper charge on your battery. An alternator is not a battery charger by any means, unless you can turn off all power consumer with the engine running, it's not going to charge the battery at a fast enough rate nor will it likely to reach full capacity.

I don't know the exact number, but there is probably 140-180 amp draw with all electronic consumers running. At that level of draw, all your alternator can do is supply power to the consumers.
What do you mean by "an alternator is not a battery charger by any means"? Of course it is! How else will the battery be charged? Nuclear reactor under the seat? We don't throw away our batteries after cranking the engine many times, or drain the battery after leaving the lights on when parked, do we?

Yes, if you somehow manage to switch on every single current drawing curcuit in your car, you might draw whatever current from the battery the alternator can supply (depending on alternator specs and engine speed), but that is beside the point as that is not a sustainable scenario, with any battery. Over a period of time, if your alternator is not charging your battery, it will die even if it has 200 amp/hr reserve capacity.

You are throwing numbers around and arriving at conclusions (as you did in your referenced post above), but you don't actually have any data as far as I can tell. What are the specs for the alternator in this car and what are some typical and maximum loads on the electrical system?

Again, the point is, if a 90 amp/hr battery can deal with CA for several weeks of parking, a 31 amp/hr battery should be able to deal with it for a couple of days. If that's not happening, the specs on the 31 amp/hr battery are suspect or it has some kind of charging issue. It is possible the Braille battery doesn't like to go through deep charging cycles on a regular basis, but I have no info on that.

I'll call Braille on Monday and try to speak with someone. But you'd think Braille would not have replaced someone's battery 3 times if they thought the problem is in the application as opposed to the product (assuming ButterzM's batteries were replaced by Braille. We do know Swamp's was).