Need ideas/input on 2nd battery

No. The owner of the company that makes the trailer told me he'd give me the info if I wanted it to share with the teardrop trailer folks, but I never took him up on it. Cricket Trailer in Houston.

Do you remember the brand of 12volt water heater?

I would think that if you are boondocking, for the most part, your generator noise isn't really going to bother anyone, so you can run enough to make some hot water.

It will stay hot for a few hours, at least hot enough for a shower.

If you are in close quarters with other people, then if you don't have shore power, or can run your generator, then you have a problem - most likely heating water in the kettle. I guess part of this depends on your routine - are you a morning shower person, or an evening shower person. I think in environments where generator use is an issue, evening showers would be more courteous to your neighbors - so maybe run as late as you can get away with and still have hot water near bedtime.

For dish washing, I almost always heat water in the kettle for the wash basin, and rinse with cold water.

In my old tag-along, I had a 12 volt, 3 liter water heater that worked really well - super hot water in about 20 mins. Didn't use a tremendous amount of juice - but I had 2 group 31 batteries and my portable solar panel. If hot water becomes a big problem, I may look into retrofitting this German water heater into my Travato.

For the laptop, I have a car charger for my Macbook Air. Ipad and Iphone have their own car chargers, but the van also has usb ports to charge with on the automotive side, and the stereo system has a usb port on the house side for charging. If you have a big juice hungry laptop, then you'd probably need a small inverter - I've seen those pocket ones that will do 200-300 watts for $20.

But if you think about it, using an inverter is a silly way to power a laptop. You're coverting dc to ac to then covert it back to dc. A car charger is available for most laptops which usually run 12 to 19 volts.

That water heater decision to run only on 120V just does not make sense. Quiet hours are usually 8 PM or 10 PM to 7 AM or 8 AM which coincides when one might want to use hot water for washing up. You are forced to seek shore power or inconveniently wait for generator hour time. Then there are many campgrounds that don't allow generators especially anywhere near tent campers. Then in a way it is very anti-boondocking for those seeking solitude in a forest. Option. Put the water in a pot and heat it up on the propane stove or go without.

Without an inverter how would you power or charge a laptop computer? One of those portable 12V plug-in inverters?

Good points. Especially if you are running those items on inverter power - not really an efficient way to run TV or sound I think.

On my rig, these items are native 12v. I ran the TV and sound system all day and into the evening and the needle did not move on the battery status. Along with changing your lights to LED, changing out your TV and entertainment systems may be a good idea for extending battery life.

I don't have an inverter and don't plan to install one. The only possible use would be to power the water heater. That would probably require a 1500 watt inverter and a 4 battery bank, and I have room for neither.

You wrote:
"It's running the furnace all night that knocks it out."
In that case adding solar panels on the roof might not be the ultimate solution. It would help starting the evening with a full battery but the same can be achieved if you have just been driving or by running the generator during the evening meal or by using your existing folding solar panel.

In our PW Excel, it turns out that the TV + DVD player + sound system draws a lot from the battery and reduces the reserve to run the furnace at night. If it is going to be a cold night, we try not to use the TV, etc. too much. It is especially true in the Fall season when night falls early and we spend more time inside. That's where books come in handy, and warm sleeping bags so that the furnace is not required all night!

Yes I've been thinking of solar on the roof. There certainly is space:

I measure 52" x 36" space there in the middle.

But how to get the wires down thru the coach to the battery pack?

I already own a 120 watt folding panel that puts out around 7 amps. I like the idea of putting it out in the sun and parking the van in the shade.

When you're driving, having solar is kinda irrelevant, as the alternator charges the house battery.

Win
Have you considered solar panels on the roof? i am considering it on mine

So how does this battery set-up work with driving in rain, snow, mud, etc. (not to even mention the clearance). Am I missing something or does this seem like the path of least resistance designing this battery compartment.

Hi AGM batteries are more or less all "deep cycle". They do require careful charging and it may be a good idea to contact the maker for specific information on charging voltage. How old is the battery?