electrical confusion on 08 bus

KampingKris wrote:
We don't use the inverter in storage. Nothing was on and the battery disconnect was also off. Thinking it was parasite battery drain for the house batteries.
Wondered if the batterytender used the house batteries to keep the chassie batteries charged - so one can always start the engine...
In that case, it makes sense that the house batteries were dead.
If we visit the rig and run the generator, that should put a charge on the house batteries... but will it do anything for the chassie batteries unless we start the engine too?

You do NOT understand the Inverter/Charger. It is 2 appliances in one.
1. It Inverts when you turn it ON
2. It is your 12 volt charging system and is AUTOMATIC anytime there is 120 power to the RV from Shore or APU (Genset).
3. The 12 volt battery disconnect does NOT kill power between the Inverter/Charger and the coach batteries. The Inverter/Charger is wired DIRECT to the coach batteries thru that 250/300 amp fuse I mentioned.
4. Visiting the rig and running the Genset will not do anything extra IF your RV is stored with 120 power to the RV. IF you Store the RV with NO 120 power, then the battery minder for the Chassis battery is dead also and will not charge the chassis batteries. Some Tiffins have a MANUAL battery disconnect also at the coach battery tray even tho they have the disconnect switch at the entry door panel.
Last, Do you store with 120 power connected to the RV? Doug

Sorry, just reread your post, you do NOT have 120 power, which means NONE of the charging systems will operate at all. BOTH the Battery tender and the Inverter/Charger. You need to get the coach batteries fully charged and have them checked for specific gravity and load tested. IF they are the original batteries and they have been DEAD a few times, they cannot be recharged and expected to hold the charge, you need to replace the coach batteries. Doug

"If we visit the rig and run the generator, that should put a charge on the house batteries... but will it do anything for the chassie batteries unless we start the engine too?"

The genset would have to run for at least 4 hours to fully charge the coach batteries, but will be useless if they are defective.
Running the Genset will activate the chassis battery tender, but IT is a low amp trickle charge appliance to MAINTAIN a full charge. Running the chassis engine WITH the Genset on will utilize BOTH the Inverter/Charger and the chassis alternator to charge the chassis batteries.
Your Inverter/Charger is about a 90 to 105 amp charger in Bulk (Fast charge) mode.