jefflbi
Senior Member
RV LIFE Pro
I don't have a fuse panel on the Inverter but the main fuse block with several 60 and 40 amp fuses is in the same compartment. I'll attach a pic. Nothing on the diagram for the fuse panel says anything about the Inverter or DC power.We need to think of batteries as somewhat like a pantry where we store food we don't need right now. The AC power feeds AC to the converter which makes DC. That DC is sent out to two different places. One is a path to the batteries, while the other goes to the fuses that are often right on the face of the converter. But there is another path which goes to the batteries! That path to and from the batteries and power will go TO the batteries at the same time as we use what goes to the fuses when we have the cord plugged in and the battey disconnect closed.
View attachment 2457575
When we have no cord power, the converter stops but if the disconnect is closed, we still get power FROM the batteries to work the RV.
The kicker can be when we have power from the cord to the converter and on to the RV, we see everything working but that can sneak up on us if the battery disconnect gets turned off while we are plugged in. The batteries are cut off from charging but the lights, etc. stay on!
I did not draw it in but there is anouther path for safety item like CO and propane detectors that they want to keep alive, even when we turn the disconnect off.
We can think we have power charging the batteries becasue we are plugged in. But if the disconnectis open power stops charge getting TO the batteris, while the safety items still use a small amount of power to kill them!
Not sure how the monitor panels are wired into this as I know they can be misleading and also far more complex and prone to failure or getting out of specs to give nmbers which may not be what we find directly on the battery posts.
Each time we add another connection in the wires, we add one more point to corrode or give us bad answers, so I like to get my voltage readings right on the battery as the part I really want to know about. IF I get different answers at different points, I have to consider there is something wrong.
So if I see my simple meter says one and the monitor another, I tend to trust the simple meter as less prone to problems when I know I put the probe on the post!
I'm not sure where the monitor panels connect. My thought would be that it reads what is at the fuses and that could be from batteries if not plugged or from the converter working when we are plugged in.
Bit of guess on that last part. But if you have no coach batteris installed and get a reading when plugged, that tells us it reads what gets to the fusesand that can be either or the combined reading.
The thing about reading battery voltage is that we are only seeing whatis at teh post. If we are putting power in at that post we see what we are adding, which really doesn't show how full the battery down inside where we can't see might have.
Sometimes called " surface charge" as it is just the reading at the surface!
Somewhat like looking in the hole of a barrel as we are filling it with something thick like syrup. As we are filling the barrel we see the syrup going in and might assume the barrel full! Even after we stop filling, if we look too soon, we may see a stack of syrup that has not spread out yet. Think really thick syrup!! Lead acid batteries work REALLY slow but if we come back in an hour we may find that stack of power has spread out to all the rest of the battery and it may be near empty!
Getting good batteris back in place may clear a lot of things as they are kind of the foundation and used for many of the control and monitoring functions like making the furnace and frig work!
Batteries are so simple but they can actually trick us in lots of small ways!
