Constant current battery chargers
I don't have AGM batteries but could someday due to the horrible location of the battery (soon to be two) on my mini MH. I read some AGM manufacturers' instructions and they say clearly do not use co...
Forum Discussion
The constant current charger would maintain the current past where the battery acceptance rate would normally start to taper that current (when the battery voltage reaches a certain point)
The "charging profile" of modern chargers is to have an initial stage (Bulk) with constant current with a current limited charger (different "sizes" of current available to choose from when buying a charger), then as the battery voltage reaches the chargers set-point for holding there for the absorption stage (Vabs) now the charger begins its stage two (Absorption) where the amps will taper. The tapering is from the battery voltage getting up closer and closer to the charger's voltage until they are the same (battery full)
So now the issue is what to pick for Vabs? Battery specs are different on that among brands and types of battery. Mostly the usual Vabs of around 14.4- 14.6 is good for AGMs or Wets. (but too high for Gels)
Note that the above profile and its "stages" has little to do with the so-called "three-stage converter" stages of 14.4,13.6 and 13.2 volts. In that case, the initial 14.4 stage is held while the battery voltage rises to 14.4 (you might get constant amps during this period, or a vaguely tapering sort of amps with a PD which can't seem to do constant amps like some others can) Now the difference is that instead of holding that 14.4 as Vabs while amps taper, some converters drop to their second stage for Absorption at some lower voltage. That makes for a longer gen time to recharge the batteries, but is considered to be more "gentle" where they can advertise it makes for a longer battery life. I'd rather have shorter gen time.
The "charging profile" of modern chargers is to have an initial stage (Bulk) with constant current with a current limited charger (different "sizes" of current available to choose from when buying a charger), then as the battery voltage reaches the chargers set-point for holding there for the absorption stage (Vabs) now the charger begins its stage two (Absorption) where the amps will taper. The tapering is from the battery voltage getting up closer and closer to the charger's voltage until they are the same (battery full)
So now the issue is what to pick for Vabs? Battery specs are different on that among brands and types of battery. Mostly the usual Vabs of around 14.4- 14.6 is good for AGMs or Wets. (but too high for Gels)
Note that the above profile and its "stages" has little to do with the so-called "three-stage converter" stages of 14.4,13.6 and 13.2 volts. In that case, the initial 14.4 stage is held while the battery voltage rises to 14.4 (you might get constant amps during this period, or a vaguely tapering sort of amps with a PD which can't seem to do constant amps like some others can) Now the difference is that instead of holding that 14.4 as Vabs while amps taper, some converters drop to their second stage for Absorption at some lower voltage. That makes for a longer gen time to recharge the batteries, but is considered to be more "gentle" where they can advertise it makes for a longer battery life. I'd rather have shorter gen time.
