Thanks to all who have replied - very helpful!
To clarify a few points raised above:
-> For my various cars over 45 years, they were / are my daily-drivers.
The battery slowly degrades until I hear slow-crank over several days. Typical life: 3-4 years.
This is my motivation to try to maintain the battery 'better, somehow'.
(Only once I had a battery suddenly & completely fail - a 2-week old battery with verified internal failure.
-> I bought this car new in 2006 and it is completely stock.
-> Regarding engine-wear driving around town in "D3" (0 to 30MPH), I collected data today during an errand (warmed-up, level road, constant speed -> low load):
"D3" -> 30MPH = 1900 RPM (3rd gear)
"D" -> 30MPH = 1300 RPM (4th gear)
There is only 600 RPM difference.
I do not consider 1300 RPM vs 1900 RPM a wear consideration for this engine.
There is no difference in gas mileage driving in "D3" around town.
Note:
In "D", it will not shift into 5th gear until 45MPH (warmed-up, level road, light load). In 5th gear at 45MPH = 1300 RPM.
So, 1300 RPM seems to be the lowest RPM it wants to cruise at.
When in "D", at less than 40MPH, if there is a small incline or the tiny movement of the gas pedal, then it will immediately down-shift from 4th-gear to 3rd-gear. This is rather annoying since it will up-shift & down-shift a lot driving around town, and for this reason various Honda Forums have agreed that leaving it in "D3" is much better to reduce transmission wear driving around town (for me, typically 30MPH or less).
-> Thanks for the Engine RPM vs Alternator Current Output Graph. I have seen similar data elsewhere, but this is the best format! Note that in a typical cold-start in the winter I am using almost every accessory (headlights, both defrosters, heated seat).
I cannot prove it, but it makes sense to me that a little higher RPM will help the alternator supply the loads, and hopefully recharge the battery at a good voltage.
However, I do have data, repeatable for years: At idle, the alternator voltage actually increases from 14.1V to 14.3V by turning on the bright lights. Whenever I do this, I conclude that that the alternator is healthy.... and I wonder why my battery lasts only 3 years...
Thanks again!
To clarify a few points raised above:
-> For my various cars over 45 years, they were / are my daily-drivers.
The battery slowly degrades until I hear slow-crank over several days. Typical life: 3-4 years.
This is my motivation to try to maintain the battery 'better, somehow'.
(Only once I had a battery suddenly & completely fail - a 2-week old battery with verified internal failure.
-> I bought this car new in 2006 and it is completely stock.
-> Regarding engine-wear driving around town in "D3" (0 to 30MPH), I collected data today during an errand (warmed-up, level road, constant speed -> low load):
"D3" -> 30MPH = 1900 RPM (3rd gear)
"D" -> 30MPH = 1300 RPM (4th gear)
There is only 600 RPM difference.
I do not consider 1300 RPM vs 1900 RPM a wear consideration for this engine.
There is no difference in gas mileage driving in "D3" around town.
Note:
In "D", it will not shift into 5th gear until 45MPH (warmed-up, level road, light load). In 5th gear at 45MPH = 1300 RPM.
So, 1300 RPM seems to be the lowest RPM it wants to cruise at.
When in "D", at less than 40MPH, if there is a small incline or the tiny movement of the gas pedal, then it will immediately down-shift from 4th-gear to 3rd-gear. This is rather annoying since it will up-shift & down-shift a lot driving around town, and for this reason various Honda Forums have agreed that leaving it in "D3" is much better to reduce transmission wear driving around town (for me, typically 30MPH or less).
-> Thanks for the Engine RPM vs Alternator Current Output Graph. I have seen similar data elsewhere, but this is the best format! Note that in a typical cold-start in the winter I am using almost every accessory (headlights, both defrosters, heated seat).
I cannot prove it, but it makes sense to me that a little higher RPM will help the alternator supply the loads, and hopefully recharge the battery at a good voltage.
However, I do have data, repeatable for years: At idle, the alternator voltage actually increases from 14.1V to 14.3V by turning on the bright lights. Whenever I do this, I conclude that that the alternator is healthy.... and I wonder why my battery lasts only 3 years...
Thanks again!