From the Manual:
"Truecharge+ has three separate DC positive terminals to allow charging
of three separate batteries (or battery banks). The total current into the
batteries is a maximum of 40 amperes, which is divided amongst the batteries according to their state of discharge.
Note: The three outputs are not independently voltage regulated so it
is important to avoid systems with mixed types of batteries."
The Remote Display Panel allows you to monitor battery charger activity
away from the charger whenever Truecharge+ is operating. The panel
displays the total charging current and the voltages of the two batteries or battery banks connected to the two positive terminals closest to the
THE THIRD WIRE IS NOT REPORTED OR ACCOUNTED FOR ON THE DISPLAY TOTAL!!
Note the wiring issue in bold which depending on your hook up may be distorting charging readings particularly if your start battery is wired in position #1 or #2 immediately to the right of the negative terminal.
If you can switch your batteris OUT of the charging circuit...run one bank down low till you get a 12.2V reading without any load on it. THEN just charge that battery bank and you should see 40amps or there is a problem. I am not a fan of 2 house banks but if you can isolate each AND the starter battery for charging, you may see better results.
The other thing I would note is that if you are simply using the panel display to read amperage, you are NOT getting the whole picture...you could be getting 39amps and never seeing anything but the 20 amp light come on. ONLY when you hit 40 amps will that lamp come on. You need to measure REAL amperage with an ammeter!
No longer posting. Reach me by PM!