Originally Posted by heslinhotel
Hi everyone! Just getting into electrical on our "new" 78 31' soverign international. PO had taken out univolt and repllaced it with ?? looks home made ala heathkit. He spared no expense with wire nuts and electrical tape. Must have blown his budget becuse there is no cover or identifing labels. Want to put in an Inteli-Power but am clueless as to what size? Need your guidence. Thanks.
Converter output is measured in DC volts and amps.
As a general rule, I size them according to the length of the trailer and the number of batteries you intend to charge since the load is shared between DC assessories and battery charging.
This was not always the case with the Univolt and older linear converters that had a separate charge line.
Newer switching converters like the Inteli-Power have one DC output only and they vary the voltage only depending on the amp load and state of charge of the battery bank. Amps are drawn from the converter by the DC accessories and battery. The battery is nothing more than another accessory willing to accept amps at a rate determined by its internal resistance.
So for a 31 foot Airstresm, I would consider 45-60 amps depending on a couple things.
If you always camp with hook-ups and never or rarely discharge your battery, 45 amps is all you will ever need based on the normal DC accessories, lights, water pump, furnace fan, radio in a 31 foot RV.
If you discharge your battery regular during boondocking, I would probably look at 50-55 amps.
If you have two batteries and boondock, you will reap the benifits of a 60 amp converter for faster initial boost charge when you run a generator or connect to shore power for charging.
Also consider the Iota DLS series and Xantrex as they both charge at a faster rate (higher volts in the Iota, power factor corrction and constant current in the Xantrex) but the Inteli-Power is a fine and capable unit too.
You have choices. good luck.