by wannabefree » Sun Aug 02, 2009 12:52 pm
The main reason is that battery chargers are designed to charge batteries, not power a trailer. The charger applies a higher than normal voltage to the battery -- not usually a problem -- but is also current limited. So when charging and running lights, etc. you are actually drawing down the battery. The battery takes longer to charge, or doesn't charge at all. Also, if you run sensitive electronics, like a computer or TV, while charging they may not like the pulsing nature of modern chargers. That said, if your load is low and needs are simple (lights) you may not have a problem at all.
There is an alternative to the somewhat overpriced converters. Get a "battery eliminator," basically a 13.8V power supply. Wire it through a relay so that when the eliminator is plugged into AC the battery is disconnected from the tear and the charger is connected to the battery. This is too techy for a post and I couldn't post the schematic to my album. So if you're interested PM me and I'll email you a simple schematic.
In anything at all, perfection is finally attained not when there is no longer anything to add, but when there is no longer anything to take away.
-- Antoine de Saint-Exupery