Battery interconnect logic
I have a recently acquired 2007 Coachmen Concord and am trying to determine just when the house and chassis batteries are connected. There are 4 wires attached to hot side of the solenoid controlling...
Forum Discussion
I do believe you're overthinking this. Multiple DC power sources (such as the alternator and solar controller) don't specifically have a hierarchy of which one supplies what power, but rather the system just reaches some point of equilibrium based on the attached load (including battery charging) and the current vs. voltage characteristics of the sources. For sources controlled by a computer or microcontroller, such as the solar charge controller or a modern vehicle's charge controller, those curves can change dynamically.
At any rate, the solar controller will supply what power it can to the system. If you're driving and the solar doesn't happen to provide enough to run the fridge, the alternator would make up the excess. I don't know that there's a particularly easy way to get it to switch to propane at that point, nor does it really seem sensible to me to do so; switching momentarily to propane every time you drove under an overpass seems like a questionable thing to do. On the other hand, I think it's a mighty useful thing to have the alternator charge the house batteries while driving, and it doesn't noticeably affect fuel mileage (especially for a motorhome, where the fuel consumed powering the alternator is negligible compared to that consumed pushing a big square box through the air at highway speeds).
As an aside, I gather you're running your RV fridge via an inverter. Do keep in the back of your mind that an RV absorption fridge uses a lot more electric power than a compressor style fridge; that's the price you pay for being able to run it on propane. If you're not able to keep up power with the solar installation, replacing it with a residential fridge might make good sense. I think most people run their RV fridges on propane when not hooked up to shore power or running a generator, rather than operating them through an inverter.
At any rate, the solar controller will supply what power it can to the system. If you're driving and the solar doesn't happen to provide enough to run the fridge, the alternator would make up the excess. I don't know that there's a particularly easy way to get it to switch to propane at that point, nor does it really seem sensible to me to do so; switching momentarily to propane every time you drove under an overpass seems like a questionable thing to do. On the other hand, I think it's a mighty useful thing to have the alternator charge the house batteries while driving, and it doesn't noticeably affect fuel mileage (especially for a motorhome, where the fuel consumed powering the alternator is negligible compared to that consumed pushing a big square box through the air at highway speeds).
As an aside, I gather you're running your RV fridge via an inverter. Do keep in the back of your mind that an RV absorption fridge uses a lot more electric power than a compressor style fridge; that's the price you pay for being able to run it on propane. If you're not able to keep up power with the solar installation, replacing it with a residential fridge might make good sense. I think most people run their RV fridges on propane when not hooked up to shore power or running a generator, rather than operating them through an inverter.
