Gunny said:
A couple points of clarification.
The product linked above is the PD9245, but it is the -14.8 model.
This means the absorption voltage, is 14.8 volts, instead of 14.4v as the models on Amazon will have.
As far as I know, Only 'bestconverter' sells this -14.8v model.
The higher absorption voltage models will charge the batteries faster, and if one is running the charger from a generator, will get the batteries to a higher state of charge in the time the generator is allowed to run.
Also Battery manufacturers like Trojan, recommend a 14.8v absorption voltage.
Does this mean that a 14.4v absorption voltage will kill the batteries prematurely? No, it means they will charge slower, and IF one is not fully recharging fully after each and every discharge cycle, the batteries will sulfate a bit quicker at 14.4 than they would at 14.8v.
Partial state of charge cycling is hard on any battery, and the higher absorption voltage helps reduce the capacity loss from doing it.
Also as batteries age the higher voltage is better to overcome the increasing battery resistance to accept the charging current.
One othe point I must make I recommend this converter, not because I think it is an Awesome product that has no flaws, but because it is one of the best options available.
With the remote/wizard/pendant, one can push a button and force the charger back to seeking absorption voltage. This is important when the alternator or solar already has the depleted batteries above 12.8v. Other charging sources might see this voltage, think the batteries are full, and then Aim for only 13.8v, or 13.2v. If the batteries are depleted they can accept a lot of amperage when the charging source is seeking high voltage of 14.4+. but when depleted and the charging source seeks only 13.6v, then ~1/3 the amps will flow, which of course greatly slows charging.
The PD allows the user to press a button and force the converter to seek 14.4 or 14.8 volts and it will hold it for 4 hours.
This feature is why I recommend the PD converters, as there is some level of user control.
PD converters are said to not meet and hold their amperage ratings on generator power.
I had a PD9245(14.4v model) in my possession for a while for a powerpack project for a friend. Its Absorption voltage was actually 14.56v. Its maximum amperage when first plugged in, with thick DC cabling to the battery was 47 amps, but this did then lower to about 41 amps. It appears related to heating, and the current is rolled back to prevent excessive heating. I did not experiment with adding more airflow/cooling to see if it would hold 45 amps the whole time upto 14.56v.
The loss of almost 5 amps of the 45 is hardly the best, but the fact it will seek and hold 14.4v for 4 hours is better than other converters( in my opinion) that have other charge profiles/algorithms.
At the end of 4 hours, if one were to dip their hydrometer, and find it still well short of 1.275+ then one can simply press the button for another 4 hours at 14.4v. If one hour later all the cells did indeed reach 1.275+, one could then and hold the button and then force the charger to hold only 13.6v, or press and hold for a bit longer and force it to hold only 13.2v.
One despicible thing about PD converters is their use of the term 'Equalization', and marketing is as a 4th stage of charging. What they do, is after 16 or 18 hours, perhaps it is 21 when holding 13.2v, it will bump voltage back upto 14.4v for 15 minutes. This causes gassing, it mixes up the electrolyte in the cells and prevents the acid from stratifying and the denser electtolyte from sinking to the bottom of the cells and eating the plates ata faster rate. This is Destratification, Not Equalization.
Equalization charging is a forced overcharge to as high as 16.2 volts, and cannot be accomplished at 14.4v
This bastardization of the term Equalization is contemptible in my opinion, and I would usually rage at any manufacturer so intentionally misleading or simply ignorant. But until a better option is presented, I will keep to my opinion that the PD series of converters is one of the best options available for a person who is not always plugged into the grid, one who actually deeply cycles their batteries, and knows and desires to return them to a true full state of charge in minimal time, and wants the option of overriding "automatic' with manual control.
The PD converters have a large finned heatsink on one side and a 80 or 92MM computer fan whose flow is divided, half to flow within the unit and half to flow across the external fins. Users should make sure this fan flow is not restricted, or that the compartment in which the converter is installed, is not closed off, as cool electronics are happy electronics.
The fan speed is variable depending on the heat the converter is making, which is directly related to how much amperage it is producing to attain or maintain a voltage setpoint. I found this fan on the unit I briefly had, would Whine annoyingly at lower speeds in a quiet environment, but my ears seem to pick up on these frequencies more than others, but the converter's location should be chosen with ventilation and this possibly annoying whining in mind. but also the location should consider the distance to the batteries, so one does not have to use super thick heavy expensive cables to minimize voltage drop to distant batteries.
Often rv manufacturers seemed to put the batteries and power distribution station very far apart from each other, then run undersized wiring to the batteries. Avoid this or rectify this. It might be OK when one is not deeply cycling their batteries, but when one does, this is a horrible recipe for premature battery destruction.
