I think any converter will be very slow at charging a Li if located 20 feet or so away and wired with wire in the #8 range as many are. With that distance and wire size the low resistance of the discharged Li tries to pull so much current that voltage drops.
I did a test yesterday with my WFCO located 20 feet away wired with #8 and the battery depleted to 67% SOC. Early in the charge current was right around 5 amps and voltage was 13.5. Current dropped very slowly over the next 6 hours to around 4 amps and voltage only went up .02 volts to 13.52, at this time SOC was 91%
3 hours later current finally dropped off to 1.4 amps and voltage rose to 13.71 with SOC at 98%. I went to bed and in the morning (10 hours later) current had dropped to near zero and voltage rose to 13.71, the SOC was still at 98%.
(At the start of the test I did an experiment by using a 30' scrap of #6 I had and temporarily added it between my converter and my battery, when I did this the current approximately doubled instantly)
The WFCO stayed in LA mode the entire time. I considered upsizing the wire but I am re-thinking that for several reasons.
1. I already have 2 other ways to bring the Li to 100% SOC easily and quickly while on shore power or while driving.
2. It is not necessary to bring the Li to 14.2V (or whatever voltage the BMS is set for to balance, some brands balance at a lower voltage) every time, as long as it is done periodically to balance the cells.
3. The LI will last longer if you don't
constantly keep it topped off.
4. Conventional wisdom (along with manufacturer's instructions) seems to recommend storing the Li at 50%-80% charged. My particular manufacturer recommends 50%.
So in my case, I don't really need the converter to bring my Li to 100%. I suspect some of you may find the same with your setups. It's not easy to ignore all we've known about lead acid all our lives but Li is a whole new story and we don't need or even want to keep them full all the time. IMHO
I ran across this thread in my research and highly recommend reading it to gain a better understanding, it sure helped me. Post #2 is especially informative but if you're geeky like me you will want to study the whole thread: https://sprinter-source.com/forums/i...threads/84295/