Originally Posted by boondocking
There is an urban myth about WFCO converters not going into Bulk mode (14.4v) and not going out of Absorb mode (13.6v). I think this is what those presenters must believe, so they shouldn't be lecturing about RV converters.
Trojan specs call for Bulk at 14.8v, Absorb at 13.6v and Float at 13.2v. Standard RV converters (WFCO, Progessive Dynamics) etc have a Bulk mode of 14.4v, Absorb mode of 13.6v and Float of 13.2v which will not hurt 2 Trojan 6v batteries in series.
You do have a three stage converter with the above specs.
Unfortunately, the urban myth has some facts behind it. Quantifying the problem isn't going to happen to really know.
It took me some dedicated testing of my batteries and RV to determine that the installed WFCO (2014 8735P) was never going to drop to trickle mode at 13.2V. My particular WFCO simply did not meet its own spec.
As for going into bulk mode, WFCO restricts bulk mode to a battery sensed at below 12V. I could never verify that my installed WFCO would ever go into bulk mode - the 40 amp fuse popped when I actually had low batteries.
The reality is that there is a steady stream of complaints similar to mine (WFCO converters don't meet their own specs). Given the huge installed base of WFCO converters, I don't know if the failure rate is abnormal or not.
I do know that those who replace the WFCO converter with a Progressive Dynamics converter are much happier with their new converter. I have verified that my PD replacement goes into boost, absorb, and trickle modes when appropriate - according to PD specs.
As for the OP's question, any 3 stage converter meeting its specs will charge any size battery bank. How fast is the only difference. In the end, a battery cannot be charged faster than 20% of its capacity per hour, and that's only if it was quite low to begin with. Fully charging a 50% charged battery at maximum rates takes at least 5 hours no matter how big the charger.
2014 Rockwood A122 A-frame