AGM vs Flooded Bulk Times
PT keeps asking whether AGMs will spend more time in Bulk at the same charging rate. I found a good example where that can be measured, using ah64id's test with his PD4655 on his pair of Lifeline...
Forum Discussion
If all loads - including batteries being charged - are connected in parallel with each other onto the output terminals of the charger or converter, then all available current from the charger or converter will be shared between the loads in accordance with the electrical equation of loads in parallel. The way the sharing works is that the lowest impedance ("resistance" in the DC world) loads get more of the current, with the lowest impedance load getting the most current.
This means that, for instance, if I have a 45 amp converter and my AGM battery bank has lower internal resistance than all other connected turned-on loads such as computers, fans, heating pads, phone chargers, lights, etc. ... then the AGM battery bank might get 37 of those 45 amps ... with the other loads getting the remaining 8 amps.
However, how much current the AGM batteries get in parallel with the other loads depends upon one more thing other than the parallel loads electrical equation. It depends upon how much the AGM batteries will accept versus the voltage winding up on their terminals. This is a vicious loop relationship: What can the batteries accept versus what voltage is on their terminals, versus the wiring size between the converter and the batteries, versus what voltage the converter can maintain directly on it's output terminals under whatever current it's delivering to all the loads simultaneously.
All of the above of course applies to each load hooked to the converter's output ... but since charging of the batteries is most likely the heaviest load, then it's best to start by having their internal resistance be as low as possible in order to take maximum advantage of the parallel load electrical relationship.
The converter has "no control" over this sharing of current among the parallel loads on it's output ... it's all up to other factors external to the converter (or any other power supply instead of a converter). By the way, the stuff above also determines how two power sources connected in parallel interact with each other and with any common parallel loads they are connected to at the same time.
I sometimes use two power supplies at once with a generator while running appliances and charging the AGM batteries when drycamping - the stock Parallax converter hooked up in parallel with an ancient Sears charger. The current actually getting to the AGM batteries is higher with this arrangement.
This means that, for instance, if I have a 45 amp converter and my AGM battery bank has lower internal resistance than all other connected turned-on loads such as computers, fans, heating pads, phone chargers, lights, etc. ... then the AGM battery bank might get 37 of those 45 amps ... with the other loads getting the remaining 8 amps.
However, how much current the AGM batteries get in parallel with the other loads depends upon one more thing other than the parallel loads electrical equation. It depends upon how much the AGM batteries will accept versus the voltage winding up on their terminals. This is a vicious loop relationship: What can the batteries accept versus what voltage is on their terminals, versus the wiring size between the converter and the batteries, versus what voltage the converter can maintain directly on it's output terminals under whatever current it's delivering to all the loads simultaneously.
All of the above of course applies to each load hooked to the converter's output ... but since charging of the batteries is most likely the heaviest load, then it's best to start by having their internal resistance be as low as possible in order to take maximum advantage of the parallel load electrical relationship.
The converter has "no control" over this sharing of current among the parallel loads on it's output ... it's all up to other factors external to the converter (or any other power supply instead of a converter). By the way, the stuff above also determines how two power sources connected in parallel interact with each other and with any common parallel loads they are connected to at the same time.
I sometimes use two power supplies at once with a generator while running appliances and charging the AGM batteries when drycamping - the stock Parallax converter hooked up in parallel with an ancient Sears charger. The current actually getting to the AGM batteries is higher with this arrangement.
