Maybe dumb question on solar

I have a dual controller on my solar system which charges both battery banks independently. On my previous coach I ran jumpers from the house to chassis battery when I was parked. However on one occasion, the chassis battery failed and discharged my house batteries before I noticed the problem. I never disconnect my batteries. Ford says that if you disconnect the chassis battery, the transmission will have to relearn your driving habits.

Check the voltage on the actual battery terminals about 2pm on a sunny day.
12.7 or less :( 13.3+ :)

My house batteries charge with the switch off!

My house batteries were the only ones being charged by solar. So I just ran a jumper to the chassis bank while parked for a long period. If your house and chassis batteries are not together you can jump around the emergency start solenoid.

LEN

My Solar controller is connected directly to the battery bank. They are the only thing connected when the batteries are disconnected. I assume most RV's have it this way.

Most commonly house batteries would charge with the disconnect switch off.

Chassis batteries typically will charge only if there is some system to charge them from the converter output, such as a BIRD (bidirectional isolator). Most commonly from the factory they would not charge, at least for units on the lower end of things. Having the disconnect switch(s) on often would not affect this.

A good and not too expensive solution to keep the chassis batteries charged is to install a Trik-L-Start or its big brother Amp-L-Start. This is basically a DC powered float/trickle charger for the chassis batteries that operates when the coach battery is being charged (that is, when the voltage is over something around 13 volts).

(If you have solar power you can use when storing your RV, why bother turning the battery disconnect switches off?)

Got voltmeter?

Normally the house batteries will charge with the "house switch " off.
But the chassis batteries will not be charged on my rig.
So the best way for you is to measure and test on a sunny day and see
if both sets are let say at 13.2 Volt or higher.
Or check the current,if you have a clip-on DC amp meter.
This way you know for sure and don't run into some problems.
Siggy