Yes, now I'm remembering that you were one of the big participants in that thread. And that thread was what alerted me to the fact that the M-B charging systems were evolving rapidly. I haven't had much time to experiment since I installed the lith batteries - no long trips yet since Jean had the MB till October. But from what I see, no matter how far down the house bank is, the alternator gives it around 14.2v at a max of about 45 or 50A - so there must be some charge management circuitry in action there. As it turns out, that voltage wont' hurt my house liths, though it won't fully charge them either.
Since I don't have solar, I only have one house charger, and it's a lith charger. I'm not sure what the M-B charging system does - whether it's multi-mode, etc. - I need to get the time to watch it and find out. But my house charger is a simple CCCV charger, which is what the lith batteries want. When first started, it charges at near its rated current (mine's rated at 60A, I actually see around 45A max, but I've never had the batteries WAY down yet) and the voltage slowly climbs to a max of 14.6 as the batteries get nearly full - that's the Constant Current part. Then the charger holds 14.6 and keeps charging until the battery climbs up to almost 14.6, with the current dropping to near or at zero as the battery gets fully charged - that's the Constant Voltage part. I've watched it do this, monitoring the house voltage and charging current over time as the battery fills up.
I'm still not sure about your 2), and I want to learn more about complex system behavior. Basically, I'd like to understand 2 things: first, if all your house chargers are configured so that they're almost the same, will the batteries still pull their charging current from the charger that's putting out the highest voltage at any particular moment? And second, if house and chassis batteries are at different voltages when connected to a single charger, will the battery with the lowest voltage take all or most the charging current?
I'm no electrical engineer, though I've had some practical experience with various systems, including a 50kw hydro site. So this stuff comes a bit slow for me. I know that in the lith world, that second issue is complex. The reason some lith batteries have internal balancing circuitry relates to this issue. Suppose a nominal 12v lith battery has four 3v banks in series. And suppose the four banks aren't balanced - that is, one is weaker or less charged than the other three. The charger will keep trying to bring up the weakest bank while the other 3 cells overcharge - unless the battery has some bank-level balancing circuitry to prevent this situation.
I bought my batteries from SmartBattery - they claim several things. First, they very carefully match each cell and each bank of cells during manufacture, so they don't need any internal balancing circuitry - and they don't provide any. Second, you can use a simple CCCV charger like the Progressive Dynamics one I bought, because all the cells will become fully charged at the same point since they're balanced - so the charger current will drop to zero and even if the charger remains on, no banks will get overcharged. That's the claim, and I don't think anybody is in a position to prove or disprove it at this point. But I want manual control of my charging systems - I'd rather be safe and stop charging at or near full charge and not risk the possibility that SmartBattery is wrong <g>... That was one of the topics of my original post on this thread. It sounds to me like you're going through similar issues and thought processes, even though our systems are pretty different.
