This train of thought began when I got impatient with the Pro-logix "resting" for hours as voltage dropped ever so slowly from 12.8 down through 12.778, 12.775, 12.771... I had been hoping to see it do an "exercise" cycle and decided to hurry things up a little by connecting an inverter on idle. I didn't take a thought and forgot about the inrush current for the caps - there was a nice sparkler affect. When I got that sorted I looked at the Pro-logix and based on the solid "charge" light, it had started a normal charge cycle. So it looks like it went from creeping down to an "exercise" cycle to cutting straight to the case and doing a regular "charge" cycle. Well and good, that sems like reasonable behavior. Probably the inverter inrush dropped the battery terminal voltage way down for a fraction of a second.
Now it seems to be cycling noticeably more slowly through the voltage steps of the charge cycle. Which probably makes sense with the idle current of the inverter and my volt meter eating part of its available charging amps. Unfortunately I don't have the instruments to check the charge current. At a gross guess the cheap 1800w inverter could idle at anywhere from 300-600 mA, maybe more. With the current to power the LED meter that's connected across the battery (500-600 mA for five 8-segment digits; at least from my quick research), good chance that's more than 1 amp - a big bite out of a 4amp max charging current.
Ok. It has been 3 hours or so and it looks like I'm not seeing an "exercise" period tonight. Has to get the batt charged and shut off before the voltage can draw down to trigger any exercise.
So with time to think (!), I then started wondering about what a parasitic draw of, say, 1.5amps would do to the maintainer programming after it had got the battery charged and stopped providing and amps during the "resting" phase. Maybe it will just slow life down a lot because the 4amp maintainer has now been effectively reduced to, maybe, a 2-1/2amp maintainer. But is it that simple?
I haven't come up with any obviously right ideas. The voltages I'm seeing across the battery (with the inverter connected and idling) seem very similar to what I observed on previous charging cycles with just the meter across the battery. They just seem to be taking longer. But I'm not sure about what this means to the low levels of current programmed for completion and resting phases. Will the maintainer increase output in those final stages to compensate for the larger draw and maintain the very low, tending to zero "resting" current? Will the charge cycle ever hit set point and end?
Not going to find out tonight. It seems to be settled around 12.35n volts, green lit, charge flashing, ticking the volts up one mV per 15-20min or so.
Now it seems to be cycling noticeably more slowly through the voltage steps of the charge cycle. Which probably makes sense with the idle current of the inverter and my volt meter eating part of its available charging amps. Unfortunately I don't have the instruments to check the charge current. At a gross guess the cheap 1800w inverter could idle at anywhere from 300-600 mA, maybe more. With the current to power the LED meter that's connected across the battery (500-600 mA for five 8-segment digits; at least from my quick research), good chance that's more than 1 amp - a big bite out of a 4amp max charging current.
Ok. It has been 3 hours or so and it looks like I'm not seeing an "exercise" period tonight. Has to get the batt charged and shut off before the voltage can draw down to trigger any exercise.
So with time to think (!), I then started wondering about what a parasitic draw of, say, 1.5amps would do to the maintainer programming after it had got the battery charged and stopped providing and amps during the "resting" phase. Maybe it will just slow life down a lot because the 4amp maintainer has now been effectively reduced to, maybe, a 2-1/2amp maintainer. But is it that simple?
I haven't come up with any obviously right ideas. The voltages I'm seeing across the battery (with the inverter connected and idling) seem very similar to what I observed on previous charging cycles with just the meter across the battery. They just seem to be taking longer. But I'm not sure about what this means to the low levels of current programmed for completion and resting phases. Will the maintainer increase output in those final stages to compensate for the larger draw and maintain the very low, tending to zero "resting" current? Will the charge cycle ever hit set point and end?
Not going to find out tonight. It seems to be settled around 12.35n volts, green lit, charge flashing, ticking the volts up one mV per 15-20min or so.