Leisure Battery 2

Can you use a cheap starting battery as an LB? Sure, people do it all the time.
People also drive around in a VW van on car tires, with no thermostat,
with a 009 distributor, missing cooling tin, and so on.

In order to properly equip your vehicle with a house power system, you need to come up with
a power budget. Every device uses a given amount of power. Add up all the power usage of the devices
you plan to use and THEN plan your LB purchase and system design.

For instance, if you hope to run a small DC-powered refrigerator expect to use about 8 Amp/Hours
just for the fridge. What this means is that, using a 100ah battery, you can only run your fridge
(and ONLY your fridge) for about 8 hours before your LB is flat. In reality, it will be less.

If you spend enough money, you could buy a much more efficient fridge, but that's not the point I'm making.
If you plan to do much in the way of camping without AC hook-ups, your money will be well spent on
efficient devices (like LED lights) and/or conservative use of electrical devices.

My 3-way fridge will run for a long time on Propane (LPG), and get colder, which uses no DC.
Westfalia wired the 3-way fridges they installed into T2s and Vanagons (T25s) so they could only
run on battery power when the engine is running for this reason.