06 Roadtrek 210 isolator/charging issue

[atcaw94]

Got a good one here, lol.

We've had the van a few months now, and it has always worked fine. I have left it on shore power at the house for the last couple weeks while working on the bed situation.

When the van is running, everything charges fine. When running off of shore power, nothing works. Here the tests I've done so far:

Van running
getting 14= volts at isolator/CB and coach batteries

Van off/Shore power
4.5v at coach batteries, and at both ends of CB on isolator

Found a 40A fuse melted coming off my isolator (battery side) going to my flex lite electric fans. There is the 40A fuse that is in line with the fans connected to a bus bar, then an additional 40A fuse between the bus bar and the isolator. Not sure how this has anything to do with my shore power problems.
I have 2 AGM 6v coach batteries.

In the second pic, are those both CB on top of the isolator? The one on the right is where I'm getting the 4.5V and the 14.5 volts.

[booster]

Was the fuse that failed a large body (maxi) like the one shown in the other place? The large ones are usually quite a lot better than equivalent size small ones, but not as good a the tubulars, I think.


Cooling fans are kind of notorious for melting connectors, fuses, and relays even in stock applications like my 96 Roadmaster wagon and that has a 40 amp fuse for each fan. The secondary fan is 300 watts and tends to melt the connector to it when they get old.


If you have even a small amount of corrosion in the connection it will get hot enough to oxidize and get progressively worse over time. If it is hot out and the fan is cycling on and off regularly without enough time to cool off, it gets even worse because the inrush in the fans is very high in many cases.



Flexalite are decent fans, but can pull more current than rated depending on the voltage and wire sizes. You probably would be wise to check the current when you fix the fuse and see how much startup and running amps they are actually taking. If they are twin fans, you can really save some problems by wiring them separately and staging them so they don't start at the same time. This is usually done by putting them on separate thermostats and setting them a bit differently.