Batteyr charging in an RV

jrnymn7 wrote:
I have looked at many rv wiring schematics, and occasionally I see one with converter power going thru the panel first, before going to the bank. Perhaps this is how Phil's rig is wired? If so, he would have to make considerable changes to his wiring layout. But, if most rv's are wired such that the converter power goes to the bank first, and then to the panel, then a buck converter would be a very simple fix.

I just went out and checked in my Itasca MH, and confirmed it's just as I stated earlier. It's a solid and sound approach the way Winnebago set it up for the components to play together:

The RV's 12 volt system gets it's power from a 12 volt fuse panel built into the Parallax converter's cabinet. The fuse panel can get it's power simultaneously from both the converter and the batteries in parallel with each other. If the converter is switched off, then the RV's 12 volt system gets it's power from only the batteries. If the battery connect/disconnect solenoid is switched off, then the RV's 12 volt system gets it's power from only the converter. If both the converter and batteries are switched off, then the RV's 12 volt system gets no power. The converter is hard wired to the 12 volt fuse panel. The line from the battery connect/disconnect solenoid is hard wired to the 12 volt fuse panel.

What all this means is there is no way for the converter to be connected ONLY to the batteries unless I remove fuses from the fuse panel that feed other 12 volt loads in the RV's 12 volt system - while at same time leaving the coach batteries connected to the converter through the fuse panel with the battery connect/disconnect solenoid switched to the connect postion.

However, having both low coach batteries and the RV's 12 volt system - in parallel with each other - hooked to the converter is not a problem in our situation because the other 12 volt loads are small in comparison to the load from low coach batteries. Hence for this situation the bulk of the converter's 45 amps is made available for charging of the batteries. The big issue for the fast charging crowd is, however, that the measly little ~13.6 volts from the converter will rarely, if ever, cause low wet cell coach batteries to accept anywhere near 45 amps from the converter.

Since our AGM batteries have low internal resistance, they will absorb 7-10 amps from the converter for several hours. Our little fuel efficient 650 watt Honda generator can therefore bring up our AGM batteries enough in 4-5 hours to "get by with" ... in light of our hit-and-run drycamping style. Sometimes we boost charge the coach batteries for 30-60 minutes using the engine alternator, then use the converter and Honda to reach a higher SOC. Both the little Honda and the idling main engine are super quiet, in consideration of any camping neighbors we might have. The big Onan is reserved for the microwave, the blender, non-propane heating, the hair dryer, and the air conditioner.

By the way, IMHO it's educational for this thread to have finally turned into a real discussion of the OP's opening points instead of beating the trolling issue to death. It's not necessary for the Original Poster to be lurking or otherwise around - whether they be a troller or not - for a sound discussion of the posted issues to have learning value. :)