acceptance charging rate AGM batteries
Hi all, It is generally thought that acceptance rate for a flooded deep cycle battery is about 12.5 amps per 100 amp-hours of capacity once the bank is at 85% state of charge. I know that accept...
Forum Discussion
Hi BFL13,
Ummm sorta both. It does depend on the cell count per jar and the number of units.
Cells are designed to provide 25 amps, so twin six volt jars in series can do 25 amps @ 12 volts comfortably. That can probably be doubled to 50 for short periods of time.
Why 25 amps? Because the battery companies all agreed to measure at that amperage.
Twin 12 volt jars have double the number of cells and are wired in parallel so they can do 50 amps (each cell is still only doing 25 amps). That, too, can be doubled to 100 (short time periods).
My (limited) understanding is that, because of lower internal resistance, starved acid AGMs exhibit lower voltage drop under load. So a large inverter could easily push a pair of six volts over the low voltage "cliff". That will happen less with 12 volt units, and even less with AGM. This is assuming all banks have the same number of amp-hours.
Starved acid run out of "bricks and mortar" before the plates can be damaged. i.e. the acid becomes "weak as water". It may shorten life span. Surplus acid (mine) you better not do that or you may end up with door stops pretty darn quick.
There are two reasons I went to surplus acid AGM. I got tired of laying in the snow to check electrolyte levels. And they were cheap because they had seen service in a cell phone tower.
In short, all AGM's are not created equal, and what is good for Lifeline (a premium battery) may destroy my surplus acid AGM jars.
Ummm sorta both. It does depend on the cell count per jar and the number of units.
Cells are designed to provide 25 amps, so twin six volt jars in series can do 25 amps @ 12 volts comfortably. That can probably be doubled to 50 for short periods of time.
Why 25 amps? Because the battery companies all agreed to measure at that amperage.
Twin 12 volt jars have double the number of cells and are wired in parallel so they can do 50 amps (each cell is still only doing 25 amps). That, too, can be doubled to 100 (short time periods).
My (limited) understanding is that, because of lower internal resistance, starved acid AGMs exhibit lower voltage drop under load. So a large inverter could easily push a pair of six volts over the low voltage "cliff". That will happen less with 12 volt units, and even less with AGM. This is assuming all banks have the same number of amp-hours.
Starved acid run out of "bricks and mortar" before the plates can be damaged. i.e. the acid becomes "weak as water". It may shorten life span. Surplus acid (mine) you better not do that or you may end up with door stops pretty darn quick.
There are two reasons I went to surplus acid AGM. I got tired of laying in the snow to check electrolyte levels. And they were cheap because they had seen service in a cell phone tower.
In short, all AGM's are not created equal, and what is good for Lifeline (a premium battery) may destroy my surplus acid AGM jars.
