[A/S] Boondocking - How Many Watt Inverter Will I Need

["qtsazmt" <qts@xxxxxxxxx>]

I/we recently purchased a 1979 31' Soverign International (in good 
shape).  Purchased it to use on our 23 acres near Yellowstone Nat. 
Park (Red Lodge. MT).  Don't have utilities to the property so will 
have to rely on batteries for power (do have a good neighbor 
downwind  who will allow me to use his water/power when necessary)  
Just purchased 2 Optima Yellow Tops because there were no batteries 
with the trailer.

Have been reading posts about replacing the Univolt that came with 
the trailer with the Intellipower 9100 + the Charge Wizard if one 
intends to do any serious booddocking (the Univolt will 
overcharge/fry the batteries?).  I know very little about electrical 
wiring, etc. other than being able to install a light switch, ceiling 
fan, etc. so a lot of this (i.e. inverter wattage) is greek to me.

I guess my questions are as follows:

*Is it necessary/a good idea to replace the Univolt (it appears to be 
in good working order but I guess I won't really know until I use the 
trailer)with the Intellipower/CW combo

*How many watts do I need for the inverter to provide (is this the 
correct terminology)?  I will basically use the batteries/power for 
light at night, the stereo (Motorola that came with and sounds 
surprisingly good for its age), whatever came stock with the 
trailer.  I don't initially intend to have a DSS system but that 
might be a possibility down the line and I would want to take this 
into account.  I also would like to switch over to an elec. fridge at 
some point if possible (is it possible to run a fridge off of battery 
power?  What about running the AC unit off of battery?

Any assistance appreciated, AJ