Expert
Posts: 3853
    
Location: Vermont | Follow the eight step program...:) http://www.phrannie.org/battery.html Switch reefer to LP and turn off unnecessary 12V appliances. Fully charge battery(s). Record the time. Shut off converter or battery charger (or unplug your RV if it's a cheapo with no way to switch it off). Run off 12 volts for 24 hours (or some convenient time) using appliances and lights as you would normally. Occasionally check a digital volt meter (see later) and record time when meter drops to each % Of Charge setting on chart (later in this poop sheet). Don't, though, go below the 50% level in this test. Simultaneously record the appliances you have running and how many minutes they run (that's each appliance, including number and type of lights, if you really want to do this right). When you reach the voltage that approximates 50% Of Charge (on chart later in this sheet), turn your battery charger back on. You now know how long you can run the house, in "normal" use, without charging, before chancing a "deep cycle." Do some simple math (below) to refine this and calculate where you can conserve electrical use to extend your time.
Edited by PaulChristenson 2012-03-18 10:08 PM
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Expert
Posts: 5870
Location: western PA | It all depends on how much and how long you will be using the DC. Our weekender has one battery, a common wet cell marine deep cycle type. Running interior lights, a water pump, water heater and fridge ignitions, it will last a couple of days. Our other trailer has two larger batteries, the kind used in marine diesel installations. If we run the furnace all night along with the other appliances, the blower motor can draw both down in about a day. Not using the furnace can increase the useful battery life to four or five days. When we last built a LQ, we installed one battery. The owner is a weekend warrier, and with three seasons under his belt, one battery has sufficed quite well. By judiciously using only the lights and water pump when they are needed, the batteries' working life can be extended. |
1 or 2 batteries
