Hi Terry,
In the standard PC wiring arrangement, there is no provision for the chassis (cranking) battery to normally receive charge current from any source but the engine alternator. The house battery bank is charged from various sources--when the rig is plugged in to AC, or if the Onan generator is running, it receives charge from the converter; if the unit is equipped with solar, it receives charge from the solar controller; and when the truck engine is running, it receives charge from the engine alternator through that relay that we were discussing in the Trik-L-Start thread you referenced. But the cranking battery does not receive any of this charge.
I emphasized the word "normally", because the one exception is with use of that "white switch" on the dash that was also being discussed in the other thread. If the white switch is depressed, it activates that relay that is normally used to send alternator charge current to the house battery bank. But with the engine not running, if the house battery bank is at a higher voltage level than the chassis battery, when the relay activates the current can flow in reverse from the house batteries to the chassis battery. That can happen if the chassis battery is somewhat dead (the original purpose of the white switch), or if the house batteries are being charged by another source--plugged in to AC, generator running, or solar charging.
Basically, all the Trik-L-Start does is bypass that relay to connect the house batteries and chassis cranking battery all the time with a one-way circuit from the house batteries to the crank battery--and let that charge current flow any time the house batteries are at a higher voltage. As pointed out by others, even with the Trik-L-Start if the house battery bank isn't being charged from some source, or at a higher voltage potential, there will be no current flow to the chassis crank battery.
To complete the picture there is one last point. The recommendation made by Keelhauler (and others) to replace the original "momentary-type" white dash switch with a permanent on/off switch can potentially provide the same effect as using the Trik-L-Start. The momentary switch only activates the big charging relay to allow charge current from the house batteries to the crank battery while the switch is held in--so it will not work for long-term charging. By replacing that momentary switch with a switch that can be left on permanently, the charge relay is held in full time and effectively can charge the chassis crank battery full time like a Trik-L-Start. I personally don't know what practical negatives can come from this, but Keelhauler has stated that (with solar charging his house batteries), he uses this method in long-term storage to keep his chassis battery charged.
To address your other point, I have seen the different revision letters on the Trik-L-Start. I would assume the higher revision letter would be a later model.
Mike
