Alternator overcharging batteries
I have 4 AGM batteries in my rig with a total capacity of 440AH (actually 880AH @ 6V, but of course they are wired to get 12V). The data sheet for my Haze batteries species a bulk -> absorption cut...
Forum Discussion
Don, my Mopar voltage regulator inside the engine computer bounces around from 13.7v to 14.9v devoid of any logic or reasoning, as far as I can determine. Soon I hope to bypass it and have a potentiometer on my Dashboard.
Lifeline AGM says when deeply cycled, a 20%, C/5 rate is the minimum initial recommended charge current. 20 amps per 100Ah battery.
Odyssey says 40 amps minimum.
Mex has previously stated that these high charge rates when depleted force acid migration through the glass matting, IIRC.
I am quite happy with my Northstar AGM's abilities to both accept and release current. Its 90AH total capacity, cranks my engine easily even at 66AH from full.
But I have to feed it those high amps(25+), and regularly bring it upto 14.46 volts until amps required to maintain 14.46v taper to 0.42, and sometimes the amount of time required to taper to 0.42 is rather obscene.
The longer in between 100% full charges, the longer the tapering stage lasts, and can be longer than the daylight available this time of year, even if I were to reach absorption voltage at 9am.
I doubt I could keep this battery happy on Solar and Alternator alone in my usage, certainly not in winter anyway.
Lifeline's 'conditioning' procedure is similar to a flooded battery equalization procedure. Like equalizing, it should not be initiated until the battery is as 'full' as it gets after a regular charging sources goes through the motions, holding proper absorption voltage for 2 to 4 hours.
The High amp recharge requirement of AGMs is not directly relatable to an Equalization charge on flooded batteries as far as I know.
I've noticed when my Northstar is full, it takes 0.0x amps to maintain 13.6v, when I temporarily crank up the voltage to 15v when it is already fully charged, amps also taper to 0.0x amps within a minute. Same with 15.3v but I have not pushed it higher than that. I've noticed no capacity loss and have not done anything remotely resembling Lifeline's conditioning procedure. It gets 40+ amps from an adjustable voltage power supply, sometimes in combination with a 25 amp schumacher, and my alternator can also provide 105+ amps to it.
I like having a battery which can enjoy these rather extreme charge currents, as opposed to tolerating them.
Also note the less expensive AGMS say to limit current to NO MORE THAN 30 amp per 100Ah of capacity, while the high Dollar AGM's can handle practically any huge number thrown at it, and laugh.
I assume 40 amps into such a battery depleted to 50% would exceed the recombination abilities of the battery, and the vents would open.
Lifeline AGM says when deeply cycled, a 20%, C/5 rate is the minimum initial recommended charge current. 20 amps per 100Ah battery.
Odyssey says 40 amps minimum.
Mex has previously stated that these high charge rates when depleted force acid migration through the glass matting, IIRC.
I am quite happy with my Northstar AGM's abilities to both accept and release current. Its 90AH total capacity, cranks my engine easily even at 66AH from full.
But I have to feed it those high amps(25+), and regularly bring it upto 14.46 volts until amps required to maintain 14.46v taper to 0.42, and sometimes the amount of time required to taper to 0.42 is rather obscene.
The longer in between 100% full charges, the longer the tapering stage lasts, and can be longer than the daylight available this time of year, even if I were to reach absorption voltage at 9am.
I doubt I could keep this battery happy on Solar and Alternator alone in my usage, certainly not in winter anyway.
Lifeline's 'conditioning' procedure is similar to a flooded battery equalization procedure. Like equalizing, it should not be initiated until the battery is as 'full' as it gets after a regular charging sources goes through the motions, holding proper absorption voltage for 2 to 4 hours.
The High amp recharge requirement of AGMs is not directly relatable to an Equalization charge on flooded batteries as far as I know.
I've noticed when my Northstar is full, it takes 0.0x amps to maintain 13.6v, when I temporarily crank up the voltage to 15v when it is already fully charged, amps also taper to 0.0x amps within a minute. Same with 15.3v but I have not pushed it higher than that. I've noticed no capacity loss and have not done anything remotely resembling Lifeline's conditioning procedure. It gets 40+ amps from an adjustable voltage power supply, sometimes in combination with a 25 amp schumacher, and my alternator can also provide 105+ amps to it.
I like having a battery which can enjoy these rather extreme charge currents, as opposed to tolerating them.
Also note the less expensive AGMS say to limit current to NO MORE THAN 30 amp per 100Ah of capacity, while the high Dollar AGM's can handle practically any huge number thrown at it, and laugh.
I assume 40 amps into such a battery depleted to 50% would exceed the recombination abilities of the battery, and the vents would open.
