I wasn't going to bother replying to this thread anymore but this has me really scratching my head wondering if you have been just pulling peoples chains or inhaling some funny smoke..
My comments in red below..
landyacht318 wrote:
My 89 with a 318 engine starter draws ~140 amps, but the engine always catches quickly.
Back when my AGm battery was newer I could hold it at 14.7 volts until my ampmeter read 0.0 amps. no doubt it was accepting somewhere around 0.025 amps or less, but that is not germain to this example.
When i would start the engine, and the alternator gets the battery back upto 14.7v, how long would it take for amps to taper back to 0.0? 0.0 amps would indicate the alternator has returned that which was used to start the engine.
So how long did it take for amps to retaper back to 0.0? under 45 seconds. Not 5 minutes, not an hour to replace that which was used to start the engine, but less than 45 seconds. So this chronic short trip driving never being able to return that which was used to start the engine is horse hockey, unless the tris were only 30 seconds long.
You need to rethink this, what you are in effect saying you drew 140A for x amount of time and the battery was INSTANTLY and fully replenished to 100% charge in 45 Seconds!
Yeah, that smells real fishy, you conveniently and fully omitted the charge current information for that 45 seconds. You would have had to been charging well above 140A and we all know that that is not going to happen.
Takes TIME along with high voltage and charging current to put that discharge current fully back in.
Your Ammeter and voltmeter I suspect was highly inaccurate..
It is a fact that many modern cars, certainly not all, are intentionally cycling the batteries so that the battery is low enough that when the brakes are hit, the voltage regulars demands 14.5ish volts and the alternator must make 40+ amps to instantly bring the ~75% charged battery to 14.7v.
???
I call BS on this, this is called "dynamic braking" I have my doubts that any vehicle manufacturer is applying this to any NON EV OR NON HEV alternator..
It would take a MASSIVE alternator to even come close to "braking" any engine larger than a lawnmower.
For example using a 140A alternator at 14.7V that is 2058W of power.
2058 W = 2.759823 hp
Even your wimpy 70s 318 would NEVER notice a 2.76 HP drag let alone affect your stopping of even a 3,000 lb vehicle..
Say your 318 had 200 HP..
That is 200 hp = 149139.974400 W, that would be a pretty impressive alternator.
Can you name one manufacturer model that IS doing this (note, you cannot use a EV OR HEV for your example, it must be a STANDARD ICE vehicle only that is using dynamic braking with the vehicles one and only alternator).
On edit, I should also add that in the '70s most alternators were low amperage, as low as 30A and very rarely you would see much above 60A.. wasn't until we got into the 90s when most manufacturers upped the game to 100A and 120A alternators..
