Help Battery issues that dont make sense

Ok I need help.
I have a 2015 42' toyhauler. With a onan 5500 Gen. It has 2 6volt interstate AGM battery I think something like 400+ amp hours combined. I also have a solar setup on the roof 400 watt system. And a WFCO 100 amp smart converter charger.  Before the last trip I took the converter charger out and tested it. It is working and does put out more when load is on the system or when the battery is low.

Ok here is the problem I am having. Battery drain is not making sense at all. and has begun becoming a problem over the last few trips. Example I went on a 2 day trip this last weekend. I had the battery's taken to Interstate, to be tested and topped off before the trip and the battery's tested perfect and topped off great. Put them in the trailer. It was super cloudy on this trip so the solar was only putting about 2-3 amps out an hour on the trip. I have been a battery **** from the time this problem reared its head. Almost no lights on in the trailer for 95% of the trip nothing used during the night other then the propane heater and fridge. It was cool outside but the heater did not run all that much maybe kicked on 5-6 times total during the night. Woke up the next day and battery's were drained down to 11.5 volts. Was able to get the gen running and it ran ALL DAY from 6am until 7pm The battery's never got back to full around 3/4 full or about 12.3 volts. One of the weird things is even with the Gen running it still shows the battery's are low. The only time I ever see good voltage on the battery's is when it is sunny out and the solar is showing 14 volts and putting in 8-10 volts into the battery bank. When its sunny out with the solar working it I can tell at that time we are running on full solar.

I just don't know what to check at this point. I don't know why the Gen running all day wont bring them back up. And I have no idea how with every single light out on the trailer all day and over night. How just running the heater and fridge can drain 2 6 volts over night. Its starting to get frustrating. Any advise would be greatly appreciated
   

Your converter charger may be good, but it seems for some reason that the charge is not getting to the batteries.  With the generator running and the converter in charge mode, check voltage on the batteries.  If I had to guess, I would say that when reconnecting the batteries a wire was left off of a battery connection.

I will check that but it still does not make sense with only the propane fridge and heater it drains them overnight. Like really does not make sense

It doesnt appear that you have calculated your battery capacity correctly. When you connect two 6 volt batteries in series, the voltage doubles, but the amp hours stay the same, so with your setup you have 210 amp hours, and 105 usuable(=50% discharged), but even if you charger is not putting a charge in the batteries, the batteries getting down to 11.5 volts, which is almost dead, is using a lot of amp hours.  Does your heater have a fan? 

"only the propane fridge and heater "

Heater?  Furnace running or electric heater? 

Furnace is propane and yes has a fan that runs and blows heat throught the ducting. Problem is guys this was not an issue for a long time it recently started happening. I used to be able to use the exterior stereo listen to music for a few hours,  with no gen on, run lights, heater all night. Something is sucking them dry overnight.

Have you double checked to make sure your fridg is on propane and not electric? 

Yes its set for LP. Check it every time I get in the trailer and turn it on

It has 2 6volt interstate AGM battery I think something like 400+ amp hours combined.

Click to expand...

More like 220-230 AH. When batteries are connected in series, the voltage doubles but the AH stays the same.

here are my thoughts

1. the WFCO converter has died
2. there is a bad connection from the converter to the battery
3. a fuse has blown
4. your solar raises the battery voltage, this re-enforces 1 thro 3 above
5. your battery is now a boat anchor, the red flag here for me is the fact that you have approx 200 Ah
of battery and a 100 Amp charger.. if the WFCO actually worked right and has bulk charged your battery over time at that level then you would reach gassing voltage real quick.. once an AGM gasses you are heading down the slope of reduced capacity very quickly.
the battery might be in a state of reduced capacity and might have enough to pass a simple load test and appear to charge, but in reality has lost some 50% capacity.. enough to run your system overnight then die quickly.

6. also the fact that you can run the genny all day and not charge confirms one of 1 thro 3 above.

7. have you set the converter for AGM ? the bulk rates are generally different, and the solar .. that too..
most AGM profiles look like this ..

Bulk = 14.4
Absorb = 14.1 to 14.7
Finish = 14.7
Eq = NONE
Float = 13.5
C-Rate = 20% of C

for FLA..
Bulk = 14.82
Absorb = 14.1 to 14.7
Finnish = 14.7
Equalize = 16.2
Float = 13.5
C-Rate = 10 to 15% of C

note the different bulk voltages...

if you charge AGM with FLA profiles then your batteries are toast real quick..

Welcome to the Forum!

The fridge on propane uses very little 12V power, but is required to operate.  Same for water heater.
The furnace uses a lot more 12V power. Propane provides the heat, but the fan uses 12V power.  That may explain the drain.

With the camper on shore power, solar OFF, check voltage at the batteries.  It should be at least 13.6V.  Repeat on genny power.  If either voltage is below 13.4V, there is a problem with the converter.

My guess is a converter problem of some type.

Though the fridge sips only a tiny amount of 12 volt when running on propane (Same for water heater) the furnace is a power hog. that big blower takes a whole lot of 12vdc.

So if you are relying on solar only. It may be you just don't have enought.

The WFCO only kicks in when you are on shore or generator power.. NOTE. IF the voltage is low. (ie: 12.4) when teh converter kick in the lights WILL BRIGHTEN. at least incandescent ones will.. LED's may or not depending on how they are built.