How much converter/charger is really needed?
I have a pair of NAPA 9824M Marine/RV batteries with a 20 hr rating of 79AH each, wired in parallel. Is there, really, any advantage in going from a 45 amp (PD4645V) converter/charger to a 55 amp (...
Forum Discussion
Problem as Mex says, is having enough power supply, (Generator VA) to run the chargers at high enough amps to do a "saturation charge" on a typical RV size bank of batteries.
The ugly graph shows the diminishing returns in time saved as you go higher in amps where the time at constant amps gets shorter and shorter. Saturation would be where that curve on the left is nearly vertical and the amps at 50% is so high that there is no bulk stage.
With saturation, you start on the absorption stage curve with amps tapering from the start. But you don't save a whole lot of time compared with the shorter bulk stage you get with a somewhat lower charging rate.
Since this is all "controlled" by the size of your generator in VA, that is your first limit. Then knowing how much of a charger that will run (where most converters have a 0.7 PF) and the size of your bank in AH, you can predict your gen time to do a 50-80 or whatever you will do.
Now you have campground generator hours or if no limit there your own time limit (or gasoline supply for the gen limit) to figure whether that is enough time to get the job done. If not, you have to equip yourself with a bigger VA generator and a higher amp charger (or go with a smaller battery bank and more solar perhaps--if there is sunshine likely)
The ugly graph shows the diminishing returns in time saved as you go higher in amps where the time at constant amps gets shorter and shorter. Saturation would be where that curve on the left is nearly vertical and the amps at 50% is so high that there is no bulk stage.
With saturation, you start on the absorption stage curve with amps tapering from the start. But you don't save a whole lot of time compared with the shorter bulk stage you get with a somewhat lower charging rate.
Since this is all "controlled" by the size of your generator in VA, that is your first limit. Then knowing how much of a charger that will run (where most converters have a 0.7 PF) and the size of your bank in AH, you can predict your gen time to do a 50-80 or whatever you will do.
Now you have campground generator hours or if no limit there your own time limit (or gasoline supply for the gen limit) to figure whether that is enough time to get the job done. If not, you have to equip yourself with a bigger VA generator and a higher amp charger (or go with a smaller battery bank and more solar perhaps--if there is sunshine likely)
